Bibliographies thématiques / RMS simulations

Sommaire

Articles de revues
Thèses
Livres
Chapitres de livres
Actes de conférences
Rapports d'organisations

Littérature scientifique sur le sujet « RMS simulations »

Auteur : Grafiati

Publié le 3 avril 2025

Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres

Choisissez une source :

Consultez les listes thématiques d’articles de revues, de livres, de thèses, de rapports de conférences et d’autres sources académiques sur le sujet « RMS simulations ».

À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.

Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.

Articles de revues sur le sujet "RMS simulations"

O’Steen, Lance, et David Werth. « The Application of an Evolutionary Algorithm to the Optimization of a Mesoscale Meteorological Model ». Journal of Applied Meteorology and Climatology 48, n^o 2 (1 février 2009) : 317–29. http://dx.doi.org/10.1175/2008jamc1967.1.

Texte intégral

Résumé :

Abstract It is shown that a simple evolutionary algorithm can optimize a set of mesoscale atmospheric model parameters with respect to agreement between the mesoscale simulation and a limited set of synthetic observations. This is illustrated using the Regional Atmospheric Modeling System (RAMS). A set of 23 RAMS parameters is optimized by minimizing a cost function based on the root-mean-square (rms) error between the RAMS simulation and synthetic data (observations derived from a separate RAMS simulation). It is found that the optimization can be done with relatively modest computer resources; therefore, operational implementation is possible. The overall number of simulations needed to obtain a specific reduction of the cost function is found to depend strongly on the procedure used to perturb the “child” parameters relative to their “parents” within the evolutionary algorithm. In addition, the choice of meteorological variables that are included in the rms error and their relative weighting are also found to be important factors in the optimization.

Styles APA, Harvard, Vancouver, ISO, etc.

Mello, Brian, et Mark Stein. « Integrative Learning and Simulating Revolution and Protest in the Middle East ». Review of Middle East Studies 55, n^o 1 (juin 2021) : 110–23. http://dx.doi.org/10.1017/rms.2021.41.

Texte intégral

Résumé :

AbstractThis essay explores insights from our experiences teaching undergraduates a set of paired history and political science courses on protest and revolution in the Middle East. Working in groups, students developed simulations of key moments of revolution or protest explored during the courses. The simulation assignment was designed to engage students in an active learning setting and as a shared assignment across both courses. The most interesting result of this project, from the teaching perspective, was its unanticipated ability to expose students to the contingency and emotion that scholarship has recently emphasized as critical to understanding social movements, but which so often falls out of the study of history and political science analyses of protest and revolution. In this paper we explore the simulation assignment, how student groups designed the simulations with limited guidance from instructors, how students took on the assigned roles by engaging deeply with the histories of the events, and how the engagement in the simulations complicated the analyses that formed the bedrock of our course readings. In our analysis we draw on two iterations of the paired courses and use both student qualitative assessments of the course and student reflections on the simulations that were included in group papers.

Styles APA, Harvard, Vancouver, ISO, etc.

Arabnejad, Mohammad Hossein, Håkan Nilsson et Rickard E. Bensow. « Scale-resolving simulations of the flow in the Francis-99 turbine at part-load condition ». IOP Conference Series : Earth and Environmental Science 1079, n^o 1 (1 septembre 2022) : 012085. http://dx.doi.org/10.1088/1755-1315/1079/1/012085.

Texte intégral

Résumé :

Abstract In this paper, we investigate the formation of the Rotating Vortex Rope (RVR) using scale-resolving methods, SAS and Wall-Modeled LES (WMLES). We compare the results from these simulation methods with the experimental data of the Francis-99 workshop. This comparison shows that the general features of the RVR can be captured with both methods. However, using WMLES methods would lead to a better quantitative agreement between the velocity profiles in the draft tube in the simulation and the experiment. The reasons for this better agreement are discussed in detail. A comparison of the pressure fluctuations in the draft tube captured in the simulations and the experiment is also presented. This comparison shows that all simulations under-predict the Root Mean Square (RMS) of these pressure fluctuations, although the RMS values predicted by the WMLES simulation are closer to the experimental values.

Styles APA, Harvard, Vancouver, ISO, etc.

Yuile, Adam, Alexander Schulz, Erik Wiss, Jens Müller et Steffen Wiese. « The Simulated Effect of Adding Solder Layers on Reactive Multilayer Films Used for Joining Processes ». Applied Sciences 12, n^o 5 (25 février 2022) : 2397. http://dx.doi.org/10.3390/app12052397.

Texte intégral

Résumé :

In order to introduce new bonding methods in the area of electronic packaging a theoretical analysis was conducted, which should give substantial information about the potential of reactive multilayer systems (rms) to create sufficient local heat for joining processes between silicon chips and ceramic substrates. For this purpose, thermal CFD (computational fluid dynamics) simulations have been carried out to simulate the temperature profile of the bonding zone during and after the reaction of the rms. This thermal analysis considers two different configurations. The first configuration consists of a silicon chip that is bonded to an LTCC-substrate (Low Temperature Co-fired Ceramics) using a bonding layer that contains an rms and a solder preform. The reaction propagation speed of the reactive multilayer was set to a value of 1 m/s, in order to partially melt a solder preform underneath a silicon chip. The second configuration, which consists only of the LTCC-substrate and the rms, was chosen to study the differences between the thermal outputs of the two arrangements. The analysis of the CFD simulations was particularly focused on interpretations of the temperature and liquid fraction contours. The CFD thermal simulation analysis conducted contains a melting/solidification model which can track the molten/solid state of the solder in addition to modelling the influence of latent heat. To provide information for the design of a test-substrate for experimental investigations, the real behaviour of Pt-100 temperature probes on the LTCC-substrate was simulated, in order to monitor an actual bonding in the experiment. All simulations were carried out using the ANSYS Fluent software.

Styles APA, Harvard, Vancouver, ISO, etc.

Philpott, Thomas, Ashish P. Agalgaonkar, Thomas Brinsmead et Kashem M. Muttaqi. « An Open-Source Julia Package for RMS Time-Domain Simulations of Power Systems ». Energies 17, n^o 22 (13 novembre 2024) : 5677. http://dx.doi.org/10.3390/en17225677.

Texte intégral

Résumé :

This paper presents RMSPowerSims.jl, an open-source Julia package for the time-domain simulation of power systems. The package is designed to be used in conjunction with PowerModels.jl, a widely used Julia package for power system optimization. RMSPowerSims.jl provides a framework for the simulation of power systems in the time domain, allowing for the study of transient stability, frequency stability, and other dynamic phenomena. The package is designed to be intuitive and flexible, allowing users to easily define custom models for network components and disturbances, while also providing a range of pre-constructed models for common power system components. RMSPowerSims.jl simplifies the process of performing RMS simulations on power system models developed using the PowerModels.jl ecosystem, and provides an easy-to-use modeling that reduces the barrier to entry for new users wishing to perform RMS simulations. The accuracy of the package is verified against DIgSILENT PowerFactory for short-circuit and load-increase disturbances, using the New England 39-bus system. The active power generation delivered by several generators in the network, and the voltage magnitudes of selected busbars are analyzed and noted to be in close agreement with those obtained using PowerFactory. The computational performance of the package is compared to that of PowerFactory and is found to be comparable for load-step simulations; however, PowerFactory is found to be considerably faster for short-circuit simulations. As computational performance is not a priority at this stage of development, this is expected, and speed optimization is planned for future work. RMSPowerSims.jl is available under an open-source license and can be downloaded from GitHub.

Styles APA, Harvard, Vancouver, ISO, etc.

Petrović, Predrag B. « Tuneable Current Mode RMS Detector ». Journal of Electrical Engineering 66, n^o 1 (1 janvier 2015) : 11–18. http://dx.doi.org/10.1515/jee-2015-0002.

Texte intégral

Résumé :

Abstract A new realization of RMS detector, employing two CCCIIs (controlled current conveyors), metal-oxide-semiconductor transistors and single grounded capacitor is present in this paper, without any external resistors and components matching requirements. The proposed circuit can be applied in measuring the RMS value of periodic, band-limited signals. The proposed circuit is very appropriate to further develop into integrated circuits. The errors related to the signal processing and errors bound were investigated and provided. To verify the theoretical analysis, the circuit PSpice simulations have also been included, showing good agreement with the theory.

Styles APA, Harvard, Vancouver, ISO, etc.

Xiao, Jianguang, Yanxin Wang, Dongmo Zhou, Chenglong He et Xiangrong Li. « Research on the Impact-Induced Deflagration Behavior by Aluminum/Teflon Projectile ». Crystals 12, n^o 4 (28 mars 2022) : 471. http://dx.doi.org/10.3390/cryst12040471.

Texte intégral

Résumé :

Although the ignition-and-growth model can simulate the ignition and detonation behavior of traditional energy materials well, it seems insufficient to simulate the impact-induced deflagration behavior of reactive materials (RMs) using current finite element codes due to their more complicated ignition threshold and lower reaction rates. Therefore, a simulation method for the impact-induced deflagration behavior of a reactive materials projectile (RMP) is developed by introducing tunable ignition threshold conditions for RMs, and a user-defined subroutine is formed by the secondary development on the equation of state (EOS). High-velocity impact experiments were performed to prove the validity of simulations. The results show that the user-defined subroutine for RMs is competent in simulating the ignition and deflagration behavior under impact conditions, because the reaction ratio, morphology and temperature distribution of RMP fragments are all well consistent with experiments, theory, and current reports from other researchers. In this way, the quantitative study on the deflagration reaction of RMs can be implemented and relevant mechanisms are revealed more clearly.

Styles APA, Harvard, Vancouver, ISO, etc.

Li, Xiaoning, Chuanhai Wang, Gang Chen, Xing Fang, Pingnan Zhang et Wenjuan Hua. « Distributed-Framework Basin Modeling System : Ⅲ. Hydraulic Modeling System ». Water 13, n^o 5 (28 février 2021) : 649. http://dx.doi.org/10.3390/w13050649.

Texte intégral

Résumé :

A distributed-framework basin modeling system (DFBMS) was developed to simulate the runoff generation and movement on a basin scale. This study is part of a series of papers on DFBMS that focuses on the hydraulic calculation methods in runoff concentration on underlying surfaces and flow movement in river networks and lakes. This paper introduces the distributed-framework river modeling system (DF-RMS) that is a professional modeling system for hydraulic modeling. The DF-RMS contains different hydrological feature units (HFUs) to simulate the runoff movement through a system of rivers, storage units, lakes, and hydraulic structures. The river network simulations were categorized into different types, including one-dimensional river branch, dendritic river network, loop river network, and intersecting river network. The DF-RMS was applied to the middle and downstream portions of the Huai River Plain in China using different HFUs for river networks and lakes. The simulation results showed great consistency with the observed data, which proves that DF-RMS is a reliable system to simulate the flow movement in river networks and lakes.

Styles APA, Harvard, Vancouver, ISO, etc.

Bollimpalli, D. A., R. Mahmoud, C. Done, P. C. Fragile, W. Kluźniak, R. Narayan et C. J. White. « Looking for the underlying cause of black hole X-ray variability in GRMHD simulations ». Monthly Notices of the Royal Astronomical Society 496, n^o 3 (23 juin 2020) : 3808–28. http://dx.doi.org/10.1093/mnras/staa1808.

Texte intégral

Résumé :

ABSTRACT Long-term observations have shown that black hole X-ray binaries exhibit strong, aperiodic variability on time-scales of a few milliseconds to seconds. The observed light curves display various characteristic features like a lognormal distribution of flux and a linear rms–flux relation, which indicate that the underlying variability process is stochastic in nature. It is also thought to be intrinsic to accretion. This variability has been modelled as inward propagating fluctuations of mass accretion rate, although the physical process driving the fluctuations remains puzzling. In this work, we analyse five exceptionally long-duration general relativistic magnetohydrodynamic (GRMHD) simulations of optically thin, geometrically thick, black hole accretion flows to look for hints of propagating fluctuations in the simulation data. We find that the accretion profiles from these simulations do show evidence for inward propagating fluctuations below the viscous frequency by featuring strong radial coherence and positive time lags when comparing smaller to larger radii, although these time lags are generally shorter than the viscous time-scale and are frequency-independent. Our simulations also support the notion that the fluctuations in $\dot{M}$ build up in a multiplicative manner, as the simulations exhibit linear rms–mass flux relations, as well as lognormal distributions of their mass fluxes. When combining the mass fluxes from the simulations with an assumed emissivity profile, we additionally find broad agreement with observed power spectra and time lags, including a recovery of the frequency dependency of the time lags.

Styles APA, Harvard, Vancouver, ISO, etc.

Zima, Beata, et Rafal Kedra. « RMS-based damage detection in reinforced concrete beams : numerical simulations ». Diagnostyka 20, n^o 4 (17 septembre 2019) : 3–10. http://dx.doi.org/10.29354/diag/112395.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Plus de sources

Thèses sur le sujet "RMS simulations"

Kalikavunkal, Priya. « Development of EMT Simulation Model to Use RMS Control Model ». Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187641.

Texte intégral

Résumé :

Evolution is continuous and as a result, developments in semiconductors are endless. This led to the Voltage Source Converter (VSC) based High Voltage Direct Current (HVDC) converter termed as HVDC light. HVDC light is quite preferable because of its pros in the technology used as well as the application it is used for. For instance, the VSC technology allows independent control of the real and reactive power and has reduced short circuit current. HVDC light are used in applications such as wind power integration, offshore power supply, underground transmission and in enhancing connected AC networks. It is vital that the control system in HVDC ensures the stability of the system and the power flow between the AC and DC systems. This is done by determining the instant at which the IGBT’s are fired in the converterstations (at both rectifier and inverter). ABB has developed RMS (using sequence components and phasors) control system based on the actual control system in a fully graphical programming language tool known as Hidraw. This RMS control has been implemented in other simulation software such as Netomac, Power factory and PSS/E. the RMS control Model is named by ABB as Common Component. The thesis aims at implementing an RMS control Model in an EMT (Electro Magnetic Transient Tools) simulation, carried out at the department of High Voltage Direct Current at ABB, Ludvika. The RMS control Model is a developed power system control and protection model which uses a simplified representation of areal time control system. When implemented, the RMS control model results are then compared with the detailed control representation implemented in PSCAD. The thesis is a result of ABB’s innovative ideas in implementing the RMS control model called Common Component into various other simulation tools of different compatibility that enables the control system to be exercised and exploited to its fullest. It also gives the prospect in developing the control system to ensure the electrical system is more efficient. The control system implemented in the EMT tool will enable developing better EMT models. The Common Component is developed but has not been implemented in PSCAD. There has been no reference to such work being carried out. Hence no reference has been referred to specific to the main work. Currently the EMT tool uses a detailed representation that shares the same code as the actual control system, MACHTM (Modular Advanced Control for HVDC) [9] control system. The implementation of Common Component in PSCAD requires an interface between them to pass the necessary parameters between them. The Common Component is developed in C++ and FORTRAN while PSCAD uses FORTRAN and hence proper interface in C++ is developed. Thereafter the electrical model representing one HVDC station (rectifier) is modelled in PSCAD. Four electrical models are implemented, described and evaluated to achieve proper control in the electrical system. The electrical models are operated in STATCOM (Static synchronous compensator) mode, where either reactive power or AC Voltage Control can be used. The model is run in reactive power control mode and the system is studied along with the control system for the required control. Model 4 gives more accurate results compared with the other models. There is better reactive power control in monitoring the PCC (point of common Coupling) and converter bus of the HVDC system. Since the Common Component is a simplified representation of the MACH [9] control system, it can behanded over to third parties without IP concerns. A simplified representation also gives the advantage of reduced simulation time. The electrical model can be further extended for both the converter stations and assessed for other control modes such as real power, dc voltage control and ac voltage control. Also the model needs to be further investigated on its behavior when subjected to faults.
Utveckling är kontinuerlig och det betyder att även utvecklingen av halvledare är oändlig. Det har lett till att en Voltage Source Converter (VSC) baserad High Voltage Direct Current (HVDC) omvandlare som kallas HVDC Light har skapats. HVDC light är att föredra på grund av dess fördelar i den teknik som används samt applikationerna den används för. Till exempel så tillåter VSC tekniken oberoende kontroll av den verkliga och reaktiva effekten och har minskat kortslutningsströmen. HVDC Light används i applikationer så som vindkraftintegration, offshore strömförsörjning, markkabelöverföring och för att förbättra anslutna växelströmsnät. Styrsystemet i HVDC säkerställer stabiliteten i systemet och kraftflödet mellan AC- och DC-system. Detta görs genom att bestämma det ögonblick då IGBT tänds i strömriktarstationerna (både likriktare och växelriktare). ABB har utvecklat ett RMS (med sekvenskomponenter och fasvektorer) styrsystem baserat på det faktiska styrsystemet i ett helt grafiskt programmeringsverktyg som kallas Hidraw. Denna RMS-kontroll har implementerats i andra simuleringsprogram såsom Netomac, Powerfactory och PSS/E. ABB kallar sin RMS-kontroll för Common Component. Avhandlingen syftar till att implementera en RMS-styrsystemsmodell i en EMT (Electro Magnetic Transient Tools) simulering som utförs vid institutionen för högspänd likström vid ABB, Ludvika. RMS-styrsystemsmodellen är ett befintligt utvecklat styr- och skyddssystem som använder en förenklad representation av det verkliga styrsystemet. När det implementerats jämförs resultaten från RMS-modelen med detaljerade styrsystemsrepresentationer som genomförts i PSCAD. Avhandlingen är ett resultat av ABBs innovativa idéer att implementera Common Component i olika simuleringsverktyg, trots deras olikheter, vilket gör det möjligt att prova och utvärdera styrsystemet maximalt. Det ger också utvecklingspotential för effektiviteten i kraftnäten. Att implementera styrsystemet i ett EMT-verktyg ger även bättre kunskap om att utveckla bättre EMT modeller. Common Component är redan utvecklad men har inte blivit implementerad i PSCAD. Det finns inga referenser till att något sådant arbete har utförts. Därför har inga sådana referenser tagits upp i rapporten. För närvarande så använder EMT verktyget en detaljerad styrsystemsrepresentation som delar samma kodbas som det verkliga styrsystemet, MACHTM (Modular Advanced Control for HVDC) [9]. Implemeteringen av Common Component i PSCAD kräver att gränssnitt mellan de båda kan överföra nödvändiga parametrar. Common Component är utvecklat i C++ och FORTRAN, PSCAD använder FORTRAN. För att kommunikationen mellan de två verktygen ska fungera har ett gränssnitt utvecklats i C++. Den elektriska modell som representerar en HVDC station (likriktaren) har tagits fram i PSCAD. Totalt har fyra olika elektriska modeller implementerats, beskrivits och utvärderats för att hitta en optimal representation. Implemeteringen av Common Component i PSCAD kräver att gränssnitt mellan de båda kan överföra nödvändiga parametrar. Common Component är utvecklat i C++ och FORTRAN, PSCAD använder FORTRAN. För att kommunikationen mellan de två verktygen ska fungera har ett gränssnitt utvecklats i C++. Den elektriska modell som representerar en HVDC station (likriktaren) har tagits fram i PSCAD. Totalt har fyra olika elektriska modeller implementerats, beskrivits och utvärderats för att hitta en optimal representation.

Styles APA, Harvard, Vancouver, ISO, etc.

Sénéchal, Dorothée. « DNS des écoulements turbulents compressibles : fluctuations de pression, de masse volumique et de température ». Paris 6, 2009. http://www.theses.fr/2009PA066106.

Texte intégral

Résumé :

Cette thèse traite du développement de méthodes numériques d'ordre élevé possédant de bonnes propriétés de capture de choc pour la résolution directe des équations Navier-Stokes compressibles. Le solveur DNS implémenté utilise des reconstructions d'ordre élevé UW et WENO/M (UW17/WENOM17) et un solveur de Riemann approché faiblement diffusif HLLC. L'intégration temporelle est implicite, précise à l'ordre deux et utilise une procédure de pas de temps dual avec sous-itérations explicites. Les calculs DNS compressibles dans un canal plan 3-D ont permis d'évaluer la dissipation numérique des schémas UW et WENO/M et l'effet de la résolution du maillage sur la prédiction des statistiques turbulentes. De nouveaux schémas d'ordre élevé (WENOM17) ont été développés. Une analyse de l'effet de la taille de boîte du canal plan sur la prédiction du champ turbulent a été réalisée. La base de données DNS compressible a permis d'effectuer une analyse détaillée de l'évolution des quantités thermodynamiques fluctuantes (', p' et T'') qui sont fortement corrélées en présence de parois isothermes. Une modélisation tensorielle de l'équation de transport pour '_rms a été proposée et validée en a priori et a posteriori. Une décomposition des fluctuations de pression en cinq termes a été appliquée aux corrélations qui interviennent dans l'équation de transport des tensions de Reynolds des modèles RSM. Cette décomposition permettra d'évaluer séparement les parties homogène et inhomogène de la diffusion de pression et du tenseur de redistribution du transport des tensions de Reynolds.

Styles APA, Harvard, Vancouver, ISO, etc.

Ostrovsky, Rafail. « Software protection and simulation on oblivious RAMs ». Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/103684.

Texte intégral

Résumé :

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1992.
Includes bibliographical references (p. 71-72).
by Rafail M. Ostrovsky.
Ph.D.

Styles APA, Harvard, Vancouver, ISO, etc.

Ton, Cuong. « Radar cross section (RCS) simulation for wind turbines ». Monterey, California : Naval Postgraduate School, 2013. http://hdl.handle.net/10945/34754.

Texte intégral

Résumé :

Approved for public release; distribution is unlimited
Wind-turbine power provides energy-independence and greenhouse-gas reduction benefits, but if wind turbines are built near military and commercial radar and communication installations, they can cause degradation in the systems performance. The purpose of this research is to study the radar cross section (RCS) of a wind turbine and assess its effect on the performance of radar and communication systems. In this research, some basic scattering characteristics of wind turbines are discussed. Several computational methods of RCS prediction are examined, citing their advantages and disadvantages. Modeling and computational issues that affect the accuracy and convergence of the simulation results are discussed. RCS simulation results for two wind turbine configurations are presented: a horizontal axis, three-blade design and a vertical axis helical design. Several methods of mitigating wind turbine clutter are discussed. Issues of RCS reduction and control for wind turbines are also addressed.

Styles APA, Harvard, Vancouver, ISO, etc.

Shao, Min 1975. « A study of RMF monitoring using DEVS simulation ». Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/80119.

Texte intégral

Résumé :

Thesis (S.B. and M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1999.
Includes bibliographical references (leaf 56).
by Min Shao.
S.B.and M.Eng.

Styles APA, Harvard, Vancouver, ISO, etc.

MORGAT, ANNE. « Contribution a l'etude structurale des p21 ras. Simulations par dynamique moleculaire de la p21 ha ras ». Paris 11, 1991. http://www.theses.fr/1991PA112159.

Texte intégral

Résumé :

La connaissance structurale approfondie des proteines ras (p21 ras) permet une meilleur comprehension des mecanismes reactionnels regulant leur activite biologique (fixation des nucleotides gdp, gtp et hydrolyse du gtp, en presence d'un ion mg ii). L'etude des complexes p21. Gppnp et p21. Gdp dans leur environnement cristallin, associee a une etude de leur surface moleculaire a montre des sites potentiels d'interactions avec d'autres macromolecules. Les proprietes dynamiques de la p21 ras complexee a une molecule de gppnp et un ion mg ii ont ete etudiees par dynamique moleculaire (programme discover). Cette simulation a apporte une meilleure connaissance des interactions entre la proteine et son ligand. L'effet de certaines mutations a pu etre evalue. Cette etude a permis d'emettre des hypotheses sur les sites d'interactions avec la proteine gap et le facteur d'echange, ainsi que sur leurs mecanismes d'action

Styles APA, Harvard, Vancouver, ISO, etc.

Gualchieri, Leonardo. « Simulation of bistatic radar experiments with deep space missions ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/9682/.

Texte intégral

Résumé :

L’obiettivo del lavoro esposto nella seguente relazione di tesi ha riguardato lo studio e la simulazione di esperimenti di radar bistatico per missioni di esplorazione planeteria. In particolare, il lavoro si è concentrato sull’uso ed il miglioramento di un simulatore software già realizzato da un consorzio di aziende ed enti di ricerca nell’ambito di uno studio dell’Agenzia Spaziale Europea (European Space Agency – ESA) finanziato nel 2008, e svolto fra il 2009 e 2010. L’azienda spagnola GMV ha coordinato lo studio, al quale presero parte anche gruppi di ricerca dell’Università di Roma “Sapienza” e dell’Università di Bologna. Il lavoro svolto si è incentrato sulla determinazione della causa di alcune inconsistenze negli output relativi alla parte del simulatore, progettato in ambiente MATLAB, finalizzato alla stima delle caratteristiche della superficie di Titano, in particolare la costante dielettrica e la rugosità media della superficie, mediante un esperimento con radar bistatico in modalità downlink eseguito dalla sonda Cassini-Huygens in orbita intorno al Titano stesso. Esperimenti con radar bistatico per lo studio di corpi celesti sono presenti nella storia dell’esplorazione spaziale fin dagli anni ’60, anche se ogni volta le apparecchiature utilizzate e le fasi di missione, durante le quali questi esperimenti erano effettuati, non sono state mai appositamente progettate per lo scopo. Da qui la necessità di progettare un simulatore per studiare varie possibili modalità di esperimenti con radar bistatico in diversi tipi di missione. In una prima fase di approccio al simulatore, il lavoro si è incentrato sullo studio della documentazione in allegato al codice così da avere un’idea generale della sua struttura e funzionamento. È seguita poi una fase di studio dettagliato, determinando lo scopo di ogni linea di codice utilizzata, nonché la verifica in letteratura delle formule e dei modelli utilizzati per la determinazione di diversi parametri. In una seconda fase il lavoro ha previsto l’intervento diretto sul codice con una serie di indagini volte a determinarne la coerenza e l’attendibilità dei risultati. Ogni indagine ha previsto una diminuzione delle ipotesi semplificative imposte al modello utilizzato in modo tale da identificare con maggiore sicurezza la parte del codice responsabile dell’inesattezza degli output del simulatore. I risultati ottenuti hanno permesso la correzione di alcune parti del codice e la determinazione della principale fonte di errore sugli output, circoscrivendo l’oggetto di studio per future indagini mirate.

Styles APA, Harvard, Vancouver, ISO, etc.

Guduff, Ludmilla. « Ultrafast diffusion-ordered NMR analysis of mixtures ». Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS239/document.

Texte intégral

Résumé :

La spectroscopie de résonance magnétique nucléaire (RMN) est un outil puissant qui permet l’étude directe de mélanges de manière non destructive. Les spectres RMN de petites molécules en solution peuvent être différenciés grâce à la stratégie DOSY (diffusion-ordered spectroscopy), une méthode de ‘chromatographie virtuelle’ qui s’appuie sur la mesure de coefficients de diffusion translationnelle. Les principaux obstacles à l’utilisation de la DOSY sont liés à la piètre sensibilité de la RMN de manière générale mais aussi à la nécessité d’introduire une dimension temporelle supplémentaire d’acquisition, ce qui va augmenter de manière significative la durée de l’expérience. Ce travail de thèse a pour objectif de mettre au point des outils inédits de RMN plus rapides et plus adaptés à la caractérisation de mélanges peu concentrés de petites molécules. Dans un premier temps, le concept de codage spatial de la diffusion dans l’expérience DOSY a été généralisé. Mis à profit dans les méthodes RMN dites ‘ultrarapides’, l’utilisation d’une dimension spatiale plutôt que temporelle pour encoder le phénomène de diffusion permet une accélération des expériences de RMN multidimensionnelles de plusieurs ordres de grandeur. L’acquisition séquentielle de spectres est remplacée par une acquisition parallèle de ces spectres dans différentes parties de l’échantillon. L’étude poussée des méthodes de DOSY rapides s’est appuyée sur des outils de simulation numérique dans le but d’améliorer la résolution des spectres et la précision des résultats. Les problèmes de sensibilité ont été abordés via le couplage des méthodes DOSY rapides avec des méthodes d’hyperpolarisation qui permettent d’augmenter l’intensité du signal. La combinaison des méthodes de diffusion conventionnelles avec les méthodes avancées de RMN ultrarapide et d’hyperpolarisation permettront des avancées significatives pour l’analyse de mélanges, en particulier les mélanges dynamiques
NMR spectroscopy is a powerful tool that allows a direct study of mixtures in a non-invasive manner. The NMR spectra of molecular species in mixtures can be separated with diffusion-ordered spectroscopy (DOSY), a ‘virtual chromatography’ approach based on the measurement of translational diffusion coefficients. Major limitation of DOSY comes from the time-dependent diffusion dimension, which results in long experiment durations, and also from the low sensitivity of NMR. The present work aims to build an innovative tool for mixtures characterization that will be faster and more efficient for low concentrated samples. We first generalized the concept of nD spatially encoded (SPEN) DOSY experiments for the analysis of complex mixtures. As bring forward by the so-called “ultrafast NMR” (UF NMR), the use of a spatial dimension to encode diffusion can accelerate experiments by several orders of magnitude since it replaces the sequential acquisition of sub-experiments by a parallel acquisition in different slices of the sample. More advanced exploration of SPENDOSY were carried out using numerical simulations for purpose of resolution and accuracy improvement. To address sensitivity issues, we then demonstrated that SPENDOSY data can be collected for hyperpolarized substrates. This particular coupling between conventional diffusion-based method with advanced techniques such as ultrafast NMR and hyperpolarization should mark a significant progress for complex mixtures analysis especially for time-evolving processes

Styles APA, Harvard, Vancouver, ISO, etc.

Veitshans, Thomas. « Propriétés des réseaux permanents ou temporaires dans les polymères : gonflement ; RMN et simulation ; RMN et écoulement ». Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10206.

Texte intégral

Résumé :

Sont presentes trois projets permettant de mieux comprendre la structure de systemes polymeres et les liens entre cette structure et les grandeurs de l'approche rmn. Dans la partie etude de gels bimodaux nous mettons en evidence une relation entre des parametres rmn et des moments de la distribution de la longueur des chaines entre deux nuds. Nous developpons en outre une version bimodale du theoreme c#* que nous verifions. Le deuxieme projet est intitule simulation de la relaxation de l'aimantation transversale d'une chaine gaussienne en solution diluee, fixee aux extremites. Nous creons un code de calcul adapte a cette premiere etude numerique dans le domaine de l'approche rmn aux systemes polymeres. Le potentiel de telles etudes est montre par une analyse de la relaxation de l'aimantation transversale m#x(t). La partie relaxation de l'aimantation transversale d'un fluide de polymeres enchevetres et soumis a un cisaillement concerne l'etude du reseau temporaire des enchevetrements. Nous presentons un dispositif original permettant d'observer par rmn des fluides cisailles. Nous avons observe qu'un cisaillement n'a pas d'influence sur la fonction m#x(t) d'une solution semi-diluee dans la gamme des taux de cisaillement etudies. Cette etude necessite d'etre completee par des etudes subsequentes que nous specifions. Par ailleurs, d'autres etudes consecutives aux trois projets de recherche sont proposees. En particulier, nous decrivons une etude qui mettrait en evidence l'objectif commun des trois projets : mieux comprendre la physique de systemes polymeres et cela grace aux moyens que nous donne l'approche rmn.

Styles APA, Harvard, Vancouver, ISO, etc.

Al-Asad, Zahir. « Implementation of NURBS Objects in a Ray TracingCode for RCS Simulation ». Thesis, Högskolan i Gävle, Ämnesavdelningen för elektronik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-7713.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Plus de sources

Livres sur le sujet "RMS simulations"

E, Demeo Martha, et Langley Research Center, dir. Real-time RMS active damping augmentation : Heavy and very light payload evaluations. Hampton, Va : National Aeronautics and Space Administration, Langley Research Center, 1994.

Trouver le texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Kahlbaum, William M. High-speed real-time animated displays on the ADAGE RDS 3000 raster graphics system. Hampton, Va : Langley Research Center, 1989.

Trouver le texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

T, McQueen Jeffrey, et Air Resources Laboratory (U.S.), dir. Applications of the Regional Atmospheric Modeling System (RAMS) at the NOAA Air Resources Laboratory. Silver Spring, Md : U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, Environmental Research Laboratories, Air Resources Laboratory, 1997.

Trouver le texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

R, Hjelmfelt Mark, Pielke Roger A et United States. National Aeronautics and Space Administration., dir. Numerical simulation of the 9-10 June 1972 Black Hills storm using CSU RAMS. [Washington, DC : National Aeronautics and Space Administration, 1997.

Trouver le texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Trouver le texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

L, Ownbey Katrina, et United States. National Aeronautics and Space Administration. Scientific and Technical Information Division., dir. High-speed real-time animated displays on the ADAGE® RDS 3000 Raster Graphics System. [Washington, DC] : National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Division, 1989.

Trouver le texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Trouver le texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

DESSLER. FRAMEWK for HUMN RES and HUMN RES SIMULATION PK. Pearson Education, Limited, 2004.

Trouver le texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Padfield, Gareth D. Helicopter Flight Dynamics : The Theory and Application of Flying Qualities and Simulation Modelling. Wiley & Sons, Incorporated, John, 2008.

Trouver le texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Alberts, Henning, Richard Bader, Jekaterina Bambeck, Daniel Baumgarten, Steffen Bier, Simon Hein, Jakob Müller et al. Risikotragfähigkeit. Erich Schmidt Verlag GmbH & Co. KG, 2025. https://doi.org/10.37307/b.978-3-503-24077-7.

Texte intégral

Résumé :

Bei Entscheidungen unter Unsicherheit reicht im Unternehmenskontext routinemäßiges Handeln meist nicht aus. Risiken müssen gründlich analysiert, bewertet und gegebenenfalls durch Maßnahmen reduziert werden. Wenn das Gesamtrisiko die Risikotragfähigkeit übersteigt, sind weitere Schritte erforderlich. Der neue Band der RMA Risk Management & Rating Association e. V. gibt Ihnen einen detaillierten Überblick über die wichtigsten Ansätze und Methoden zur Berechnung der Risikotragfähigkeit und ihrer Einbindung in betriebliche Entscheidungsprozesse. Ein umfangreicher Praxisteil mit aktuellen Beispielen – u.a. einer Monte-Carlo-Simulation bei einem DAX-Konzern – unterstützt Sie beim Vertiefen und Anwenden.

Styles APA, Harvard, Vancouver, ISO, etc.

Plus de sources

Chapitres de livres sur le sujet "RMS simulations"

Castelli, Silvia Trini, Tamir Gustavo Reisin et Gianni Tinarelli. « Comparison of RAMS, RMS and MSS Modelling Systems for High Resolution Simulations in Presence of Obstacles for the MUST Field Experiment ». Dans Air Pollution Modeling and its Application XXI, 9–14. Dordrecht : Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-1359-8_2.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Kubicki, James D., et Heath D. Watts. « 3. Reaction Mechanisms and Solid–Gas Phase Reactions : Theory and Density Functional Theory Simulations ». Dans High Temperature Gas-Solid Reactions in Earth and Planetary Processes, sous la direction de Penelope King, Bruce Fegley et Terry Seward, 85–102. Berlin, Boston : De Gruyter, 2018. http://dx.doi.org/10.1515/rmg.2018.84.3.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

De Mattia, Salvatore. « SWORD RAS Project ». Dans Modelling and Simulation for Autonomous Systems, 345–56. Cham : Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-98260-7_22.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Sherif, Mohsen, Abdel Azim Ebraheem, Ampar Shetty, Ahmed Sefelnasr, Khaled Alghafli et Mohamed Al Asam. « Evaluation of the Effect of the Wadi Bih Dam on Groundwater Recharge, UAE ». Dans Natural Disaster Science and Mitigation Engineering : DPRI reports, 509–27. Singapore : Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-2904-4_21.

Texte intégral

Résumé :

AbstractIn Ras Al Khaimah, UAE, groundwater from the alluvial aquifer in Wadi Bih was the only source of freshwater for various uses prior to the construction of a seawater desalination plant in 1998. This study was conducted to evaluate the effect of the Wadi Bih dam on groundwater resources and to increase knowledge of the hydrodynamics of the aquifer. A local-scale numerical groundwater flow model was developed and used to investigate the impacts of different groundwater management options on groundwater resources. The calibrated and validated model was defined as the base case, and subsequently, simulations were performed to analyze different management scenarios. The simulations indicated that maximum recharge occurred during years of high rainfall (1995–1998). Minimum recharge occurred in 2000, 2002, and 2004. The major contribution to the water balance was from subsurface inflows from the upper wadi zone and the two tributaries. Overall, the annual water balance was negative in most years, with an average net decline of 0.6 MCM per year, indicating a slow but continuous depletion of groundwater resources. At the end of the simulation, the total groundwater recharge due to rainfall and water storage in the ponding area was 9.81 MCM.

Styles APA, Harvard, Vancouver, ISO, etc.

Newman, Wyatt S. « Simulation in ROS ». Dans A Systematic Approach to Learning Robot Programming with ROS, 95–151. Boca Raton : CRC Press, [2017] : Chapman and Hall/CRC, 2017. http://dx.doi.org/10.1201/9781315152691-5.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Walko, Robert L., et Roger A. Pielke. « Simulations of Project WIND Cases with RAMS ». Dans Mesoscale Modeling of the Atmosphere, 97–121. Boston, MA : American Meteorological Society, 1994. http://dx.doi.org/10.1007/978-1-935704-12-6_11.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Subramanian, Rajesh. « Robot Simulation and Visualization ». Dans Build Autonomous Mobile Robot from Scratch using ROS, 261–84. Berkeley, CA : Apress, 2023. http://dx.doi.org/10.1007/978-1-4842-9645-5_5.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Jacobsen, Abigail. « Optimizing Manufacturing Operations and Managing Supply Chain Risk with Monte Carlo Simulation ». Dans Risikomanagement-Schriftenreihe der RMA, 53–62. Berlin : Erich Schmidt Verlag GmbH & Co. KG, 2024. http://dx.doi.org/10.37307/b.978-3-503-23826-2.04.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Subramanian, Rajesh. « Setting Up a Workstation for Simulation ». Dans Build Autonomous Mobile Robot from Scratch using ROS, 89–130. Berkeley, CA : Apress, 2023. http://dx.doi.org/10.1007/978-1-4842-9645-5_3.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Aouine, Mimoun, Claude Esnouf et Thierry Epicier. « Simulation of EDS Spectra Using X-RES Software ». Dans Microbeam and Nanobeam Analysis, 233–40. Vienna : Springer Vienna, 1996. http://dx.doi.org/10.1007/978-3-7091-6555-3_14.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Actes de conférences sur le sujet "RMS simulations"

Ivanov, Chavdar, Georgii Tishenin, Damiano Lanzarotto, Florent Morel et Antonello Monti. « Standardized Model Exchange of HVDC Equipment for RMS and EMT Simulations ». Dans 2024 IEEE PES Innovative Smart Grid Technologies Europe (ISGT EUROPE), 1–5. IEEE, 2024. https://doi.org/10.1109/isgteurope62998.2024.10863427.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Lopez, Mark, Mark Tischler, Kenny Cheung, J. V. R. Prasad et Marc Takahashi. « Simulating HHC/AFCS Interaction and Optimized Controllers using Piloted Maneuvers ». Dans Vertical Flight Society 71st Annual Forum & Technology Display, 1–13. The Vertical Flight Society, 2015. http://dx.doi.org/10.4050/f-0071-2015-10214.

Texte intégral

Résumé :

Higher harmonic control (HHC) has been shown to be capable of reducing vibration and noise in rotorcraft. The majority of the previous work has concentrated on the HHC itself, and not the interaction between the automatic flight control system (AFCS) and HHC. Limited studies have been done on HHC/AFCS interaction using a linear time invariant (LTI) model and offline inputs including the use of dynamic crossfeeds to improve HHC performance while maneuvering. Most recently, results on HHC/AFCS interaction using nonlinear piloted simulations have been obtained. It has been observed that the nominal T-matrix controller approach, while effective in steady state, does not reduce vibration during a maneuver. Increasing the feedback gain can slightly improve RMS and settling time but magnifies peak response. The aim of the current work is to optimize HHC controller performance in a realistic piloted maneuver, and validate the design on a nonlinear simulation model. Achieving this objective required the following accomplishments: 1) Extraction, reduction, and validation of a linear time invariant model from a nonlinear model. 2) Baseline higher harmonic controller design and validation based on the linear model applied to the nonlinear model. 3) Optimization of the higher harmonic controller design to improve performance during a maneuver while maintaining stability. 4) Fitting ideal crossfeeds with a low-order approximation. 5) Implementation of crossfeeds to further improve vibration controller performance during a maneuver.

Styles APA, Harvard, Vancouver, ISO, etc.

Espinoza, Renzo Fabián, et Paulo Godoy. « OpenDSS-Based Real-Time RMS Simulator : Design and Applications ». Dans 2024 Open Source Modelling and Simulation of Energy Systems (OSMSES), 1–7. IEEE, 2024. http://dx.doi.org/10.1109/osmses62085.2024.10668999.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Venters, Ravon, Brian Helenbrook et Goodarz Ahmadi. « Numerical Simulations of Turbulent Flow Through a 90° Elbow ». Dans ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/ajkfluids2019-5498.

Texte intégral

Résumé :

Abstract Turbulent flow in an elbow has been numerically investigated. The flow was modeled using two approaches; Reynolds Averaged Navier-Stokes (RANS) and Direct Numerical Simulation (DNS) methods. The DNS allows for all the scales of turbulence to be evaluated, providing a detailed depiction of the flow. The RANS simulation, which is typically used in industry, evaluates time-averaged components of the flow. The numerical results are accompanied by experimental data, which was used to validate the two methods. Profiles of the mean and root-mean-square (RMS) fluctuating components were compared at various points along the midplane of the elbow. Upstream of the elbow, the predicted mean and RMS velocities from the RANS and DNS simulations compared well with the experiment, differing slightly near the walls. However, downstream of the elbow, the RANS deviated from the experiment and DNS, showing a longer region of flow re-circulation. This caused the mean and RMS velocities to significantly differ. Examining the cross-section flow field, secondary motion was clearly present. Upstream secondary motion of the first kind was observed which is caused by anisotropy of the reynolds stresses in the turbulent flow. Downstream of the bend, the flow transitions to secondary motion of the second kind which is caused by streamline curvature. Qualitatively, the RANS and DNS showed similar results upstream of the bend, however downstream, the magnitude of the secondary motion differed significantly.

Styles APA, Harvard, Vancouver, ISO, etc.

Sommerville, Stephen, Gareth A. Taylor et Maysam Abbod. « Potential Benefits and Challenges of Employing Inertia Distribution Indexing in RMS Simulations ». Dans 2023 58th International Universities Power Engineering Conference (UPEC). IEEE, 2023. http://dx.doi.org/10.1109/upec57427.2023.10295005.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Ho¨lzer, Andreas, et Martin Sommerfeld. « Transport of Non-Spherical Particles in Turbulence : Application of the LBM ». Dans ASME 2006 2nd Joint U.S.-European Fluids Engineering Summer Meeting Collocated With the 14th International Conference on Nuclear Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/fedsm2006-98329.

Texte intégral

Résumé :

Direct numerical simulations of the motion of volume equivalent single cylindrical particles with axis ratios of 1, 2, 3, and 4 and Stokes numbers of 1, 2, 4, and 40 in a homogeneous isotropic turbulent flow field are presented. The forced turbulent flow is simulated using the Lattice Boltzmann Method (LBM). It is observed that the rms velocity and the rms angular velocity in longitudinal and in radial direction are identical for every particle, even though the rms forces can differ more than 100% and the rms torque more than 1000% in both directions. However, these differences in force and torque result in a different short-time behaviour of the particle in longitudinal and in radial direction. The rms particle velocity is found to decrease with increasing axis ratio and the rms particle angular velocity to have a maximum at an axis ratio of about 2.5. The ratio of the rms velocity of the particle to that of the fluid decreases with increasing Stokes number as well as the ratio between the rms angular velocities, as one could expect.

Styles APA, Harvard, Vancouver, ISO, etc.

Ameen, Muhsin M., Xiaofeng Yang, Tang-Wei Kuo et Sibendu Som. « Using LES to Simulate Cycle-to-Cycle Variability During the Gas Exchange Process ». Dans ASME 2017 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/icef2017-3591.

Texte intégral

Résumé :

In spark ignition (SI) engines, high efficiencies are typically obtained near limits of stable operation which may result in high cycle-to-cycle variations (CCV). Traditional computational fluid dynamics (CFD) tools like Reynolds-averaged Navier-Stokes simulations (RANS) may not predict the CCV in engines. Higher fidelity CFD tools like large-eddy simulations (LES) have been shown to capture these CCV. In this paper, LES of a motored transparent combustion chamber (TCC) engine is performed to simulate the CCV introduced during the gas exchange process. A grid convergence study is performed, and it is shown that using a 1 mm in-cylinder grid size leads to similar flowfield statistics as compared to using a 0.5 mm in-cylinder grid size. The phase-averaged mean and root mean square (RMS) flowfields predicted by LES are validated comprehensively using particle image velocimetry (PIV) measurements. The validation is performed for 4 different crank angles, corresponding to the intake, compression, expansion and exhaust strokes, and for three different measurement planes. It is shown that LES is able to accurately predict the mean velocities, whereas the RMS velocity magnitudes are under-predicted. The inaccuracy in the RMS velocities are largest during the intake stroke, whereas good agreement with the measurements is observed during the expansion and exhaust strokes. A similarity index analysis provides a quantitative measure of the number of cycles that are required to be simulated to capture the flowfield statistics. This analysis is applied to both the PIV dataset and CFD dataset. It is shown that approximately 20 cycles are sufficient to obtain converged mean and RMS flowfields from the simulations, whereas the PIV measurements require approximately 40 cycles. Faster convergence for the LES results is because the simulations do not take into account additional uncertainties in the rpm, plenum pressures, boundary temperatures and so on, which are present in the experiments.

Styles APA, Harvard, Vancouver, ISO, etc.

van Essen, Sanne, Tim Bunnik et Jule Scharnke. « Statistical Uncertainty of Ship Response to Waves As a Function of Test Duration ». Dans ASME 2024 43rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2024. http://dx.doi.org/10.1115/omae2024-122486.

Texte intégral

Résumé :

Abstract Wave-induced ship responses have a natural statistical variability, due to the nature of the ocean waves. This needs to be accounted for in ship design. The uncertainty and extreme values of the ship motions and loads depend on the test or simulation duration. This paper presents the experimental relation between uncertainty of root-mean-square (RMS) and most probable maximum (MPM) response values and the test duration, for a sailing ferry in steep bow-quartering waves. The RMSE uncertainty of the RMS of heave, pitch and relative wave elevation was 2–3% after 0.5 h test duration, reducing to 1% after 1 h. The uncertainty of the measured significant wave height was similar. For MPM values with a low uncertainty you need to perform longer tests. The RMSE uncertainty of the MPM of heave and pitch motions was 12% after 2 h, reducing to 5% after 5 h. This uncertainty is lower for relative wave elevation (2–6% after 2 h; 1–3% after 5 h), and higher for green water force on the accommodation (55–65% after 2 h; 20–40% after 5 h). We cannot use linear simulations to predict the RMS or MPM response values themselves, but we can use them to predict the required experimental duration for a given error tolerance of the RMS of (relative) motions.

Styles APA, Harvard, Vancouver, ISO, etc.

DesJardin, Paul E., Sheldon R. Tieszen, Timothy J. O’Hern et Andrew L. Gerhart. « Numerical Predictions and Experimental Measurements of the Near-Field of a Large Turbulent Helium Plume ». Dans ASME 2000 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/imece2000-2080.

Texte intégral

Résumé :

Abstract Measurements of a large, 1 m in diameter, turbulent buoyant helium plume are taken and compared to results from numerical simulation. The experiments are carried out in Sandia’s FLAME (Fire Laboratory for Accreditation of Model by Experimentation) facility and consist of a low velocity (0.351 m/s) helium plume emitting upwards into ambient air with low velocity co-flow air supplied radially to minimize the effects of the test chamber walls. The measurement approach consists of measurements of time-resolved instantaneous velocity using Particle Image Velocimetry (PIV). The numerical simulations are based on the use of the Large Eddy Simulation (LES). Results from this study show excellent agreement between the LES and experimental data for puffing frequency and mean and RMS streamwise velocity for downstream locations of X/Dp > 0.5. For locations very near the base of the plume (i.e. X/Dp < 0.5) the LES over-predicts the streamwise mean and RMS velocity and under-predicts the mean and RMS cross-stream velocities. In addition, the prediction of velocities near the base of the plume exhibit a strong sensitivity to grid resolution. This sensitivity suggests the need for modification of the current dynamic Smagorinsky and gradient diffusion turbulence models to account for the effects of subgrid scale buoyancy.

Styles APA, Harvard, Vancouver, ISO, etc.

Santos, D. R., A. R. Fioravanti, V. E. Botechia et D. J. Schiozer. « Optimizing Well Control Strategies with IDLHC-MLR : A Machine Learning Approach to Address Geological Uncertainties and Reduce Simulations ». Dans Offshore Technology Conference Brasil. OTC, 2023. http://dx.doi.org/10.4043/32985-ms.

Texte intégral

Résumé :

Abstract This paper presents an advanced version of the previous IDLHC-ML approach, designed to enhance life-cycle well control optimization by reducing simulations. Unlike its predecessor, this updated method, called IDLHC-MLR, uses representative models (RMs) to address the effect of geological uncertainties on production strategies. Despite presenting additional computational challenges, considering uncertainties in determining effective strategies is crucial, making the new IDLHC-MLR approach a valuable solution. The IDLHC-MLR combines the iterative discrete Latin hypercube optimization algorithm (IDLHC) with machine learning (ML) to robustly optimize the well's bottom-hole pressure (BHP) throughout the field management period. The method is applied to the UNISIM-I-M benchmark of Namorado Field, located in the Campos Basin, Brazil. The IDLHC-MLR method trains the initial ML model with well BHP strategies robustly applied to all RMs in the first iteration of IDLHC. In subsequent iterations, the trained ML model is used to predict the expected monetary value of the RMs, and only a subset of new strategies with the highest expected outcome is selected for simulation. In addition, the ML algorithms are retrained with newly generated strategies over the iterations to improve the model's accuracy. The IDLHC-MLR incorporates stacked ensemble learning, which leverages predictions from various base machine learning models to train a secondary algorithm. In this approach, the IDLHC-MLR employs multiple base learners such as Lasso, Gradient Boosting, and Random Forest to make predictions, which are then inputted into a multi-layer perceptron for training purposes. This integration of multiple base models results in a more robust and accurate prediction and provides a 45% reduction in the number of simulations required compared to the traditional IDLHC model while maintaining similar expected monetary value. To conclude, utilizing inexpensive ML models effectively reduces computational time by substituting costly full-physics reservoir simulations. The significant computational time required for full-physics simulations, particularly when considering multiple scenarios to account for uncertainties, can pose a challenge to meeting project deadlines. The IDLHC-MLR methodology, incorporating low-cost ML models, offers a practical solution to reduce computational time, increasing the likelihood of successful project implementation within the given timeline.

Styles APA, Harvard, Vancouver, ISO, etc.

Rapports d'organisations sur le sujet "RMS simulations"

Reis, Evan. Seismic Performance of Single-Family Wood-Frame Houses : Comparing Analytical and Industry Catastrophe Models (PEER-CEA Project). Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, décembre 2020. http://dx.doi.org/10.55461/qmbu3779.

Texte intégral

Résumé :

This report is one of a series of reports documenting the methods and findings of a multi-year, multi-disciplinary project coordinated by the Pacific Earthquake Engineering Research Center (PEER and funded by the California Earthquake Authority (CEA). The overall project is titled “Quantifying the Performance of Retrofit of Cripple Walls and Sill Anchorage in Single-Family Wood-Frame Buildings,” henceforth referred to as the “PEER–CEA Project.” The overall objective of the PEER–CEA Project is to provide scientifically based information (e.g., testing, analysis, and resulting loss models) that measure and assess the effectiveness of seismic retrofit to reduce the risk of damage and associated losses (repair costs) of wood-frame houses with cripple wall and sill anchorage deficiencies as well as retrofitted conditions that address those deficiencies. Tasks that support and inform the loss-modeling effort are: (1) collecting and summarizing existing information and results of previous research on the performance of wood-frame houses; (2) identifying construction features to characterize alternative variants of wood-frame houses; (3) characterizing earthquake hazard and ground motions at representative sites in California; (4) developing cyclic loading protocols and conducting laboratory tests of cripple wall panels, wood-frame wall subassemblies, and sill anchorages to measure and document their response (strength and stiffness) under cyclic loading; and (5) the computer modeling, simulations, and the development of loss models as informed by a workshop with claims adjustors. This report is a product of Working Group (WG) 6: Catastrophe Modeler Comparisons and focuses on comparing damage functions developed by the PEER–CEA Project with those currently contained in modeling software developed by the three largest insurance catastrophe modelers: RMS, CoreLogic and AIR Worldwide. A semi-blind study was conducted in collaboration with the modeling companies to compare damage estimates for a selection of the Index Buildings developed in the PEER–CEA Project Study. The WG6 Project Team conducted several meetings with these modeling companies to gather feedback on the structure of and assumptions made by the PEER–CEA Project. The comparative results are evaluated and presented herein.

Styles APA, Harvard, Vancouver, ISO, etc.

Zhang, Zhonglong, Billy Johnson et Blair Greimann. HEC-RAS-RVSM (Riparian Vegetation Simulation Module). Engineer Research and Development Center (U.S.), juin 2019. http://dx.doi.org/10.21079/11681/32864.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Steinbock, Thilo, et Klemens Kerssen. Evaluation on the capabilities of MATLAB Simulink’s Embedded Coder for rapid prototyping of micro-controller based control systems for switching converters. Universitatsbibliothek Kiel, mars 2025. https://doi.org/10.38071/2025-00178-9.

Texte intégral

Résumé :

Switching converters play a crucial role in modern power electronics, offering efficient voltage conversion in various electronic devices. This paper presents an approach to the rapid prototyping for micro-controller based control systems, applied to the buck-converter topology. The methodology utilized features from MATLAB Simulink and it’s Embedded Coder extension to model and implement the control system, enabling a simplified transition from simulation to hardware implementation. For this purpose the paper evaluates two control systems, namely the error-amplifier and the PID controller. Comparative analysis reveals insights on the startup behavior, RMS voltage, peak-to-peak voltage and maximum voltage. While the simulation outperformed the measurements of the hardware implementation in most parts, this paper still underscores the utility of MATLAB Simulink’s Embedded Coder for rapid prototyping and hardware-in-the-loop development of switching converter control systems.

Styles APA, Harvard, Vancouver, ISO, etc.

Meot, F., V. Ptitsyn, V. Ranjbar et D. Rubin. Polarized e-bunch acceleration at Cornell RCS : Tentative tracking simulations. Office of Scientific and Technical Information (OSTI), octobre 2017. http://dx.doi.org/10.2172/1408712.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Letcher, Theodore, Julie Parno, Zoe Courville, Lauren Farnsworth et Jason Olivier. A generalized photon-tracking approach to simulate spectral snow albedo and transmittance using X-ray microtomography and geometric optics. Engineer Research and Development Center (U.S.), juin 2023. http://dx.doi.org/10.21079/11681/47122.

Texte intégral

Résumé :

A majority of snow radiative transfer models (RTMs) treat snow as a collection of idealized grains rather than an organized ice–air matrix. Here we present a generalized multi-layer photon-tracking RTM that simulates light reflectance and transmittance of snow based on X-ray micro- tomography images, treating snow as a coherent 3D structure rather than a collection of grains. The model uses a blended approach to expand ray-tracing techniques applied to sub-1 cm3 snow samples to snowpacks of arbitrary depths. While this framework has many potential applications, this study’s effort is focused on simulating reflectance and transmittance in the visible and near infrared (NIR) through thin snow- packs as this is relevant for surface energy balance and remote sensing applications. We demonstrate that this framework fits well within the context of previous work and capably reproduces many known optical properties of a snow surface, including the dependence of spectral reflectance on the snow specific surface area and incident zenith angle as well as the surface bidirectional reflectance distribution function (BRDF). To evaluate the model, we compare it against reflectance data collected with a spectroradiometer at a field site in east-central Vermont. In this experiment, painted panels were inserted at various depths beneath the snow to emulate thin snow. The model compares remarkably well against the reflectance measured with a spectroradiometer, with an average RMSE of 0.03 in the 400–1600 nm range. Sensitivity simulations using this model indicate that snow transmittance is greatest in the visible wavelengths, limiting light penetration to the top 6 cm of the snowpack for fine-grain snow but increasing to 12 cm for coarse-grain snow. These results suggest that the 5% transmission depth in snow can vary by over 6 cm according to the snow type.

Styles APA, Harvard, Vancouver, ISO, etc.

Depriest, Kendall. Radiation Transport Simulation of the Sulfur Counting System in the Radiation Metrology Laboratory (RML). Office of Scientific and Technical Information (OSTI), mai 2021. http://dx.doi.org/10.2172/1787741.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Christie, Benjamin, Osama Ennasr et Garry Glaspell. Autonomous navigation and mapping in a simulated environment. Engineer Research and Development Center (U.S.), septembre 2021. http://dx.doi.org/10.21079/11681/42006.

Texte intégral

Résumé :

Unknown Environment Exploration (UEE) with an Unmanned Ground Vehicle (UGV) is extremely challenging. This report investigates a frontier exploration approach, in simulation, that leverages Simultaneous Localization And Mapping (SLAM) to efficiently explore unknown areas by finding navigable routes. The solution utilizes a diverse sensor payload that includes wheel encoders, three-dimensional (3-D) LIDAR, and Red, Green, Blue and Depth (RGBD) cameras. The main goal of this effort is to leverage frontier-based exploration with a UGV to produce a 3-D map (up to 10 cm resolution). The solution provided leverages the Robot Operating System (ROS).

Styles APA, Harvard, Vancouver, ISO, etc.

O'Brien, James G., Emily L. Barrett, Xiaoyuan Fan, Ruisheng Diao, Renke Huang et Qiuhua Huang. Adaptive RAS/SPS System Settings for Improving Grid Reliability and Asset Utilization through Predictive Simulation and Controls. Office of Scientific and Technical Information (OSTI), novembre 2017. http://dx.doi.org/10.2172/1580707.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Corum, Zachary, Ethan Cheng, Stanford Gibson et Travis Dahl. Optimization of reach-scale gravel nourishment on the Green River below Howard Hanson Dam, King County, Washington. Engineer Research and Development Center (U.S.), avril 2022. http://dx.doi.org/10.21079/11681/43887.

Texte intégral

Résumé :

The US Army Corps of Engineers, Seattle District, nourishes gravel downstream of Howard Hanson Dam (HHD) on the Green River in Washington State. The study team developed numerical models to support the ongoing salmonid habitat improvement mission downstream of HHD. Recent advancements in computing and numerical modeling software make long-term simulations in steep, gravel, cobble, and boulder river environments cost effective. The team calibrated mobile-bed, sediment-transport models for the pre-dam and post-dam periods. The modeling explored geomorphic responses to flow and sediment regime changes associated with HHD construction and operation. The team found that pre-dam conditions were significantly more dynamic than post-dam conditions and may have had lower spawning habitat quality in the project vicinity. The team applied the Bank Stability and Toe Erosion Model to the site and then calibrated to the post-dam gravel augmentation period. The team implemented a new hiding routine in HEC-RAS that improved the simulated grain size trends but underestimated coarse sediment transport. Models without the hiding function overestimated grain size but matched bed elevations and mass flux very well. Decade-long simulations of four future gravel nourishment conditions showed continued sediment storage in the reach. The storage rate was sensitive to nourishment mass and grain size.

Styles APA, Harvard, Vancouver, ISO, etc.

Gibson, Stanford, et James Crain. Modeling sediment concentrations during a drawdown reservoir flush : simulating the Fall Creek operations with HEC-RAS. Engineer Research and Development Center (U.S.), août 2019. http://dx.doi.org/10.21079/11681/33884.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Nous offrons des réductions sur tous les plans premium pour les auteurs dont les œuvres sont incluses dans des sélections littéraires thématiques. Contactez-nous pour obtenir un code promo unique!