Journal articles: 'Fluid dynamics – Computer simulation'

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Li, Lei, Carlos F. Lange, and Yongsheng Ma. "Association of design and computational fluid dynamics simulation intent in flow control product optimization." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 232, no. 13 (March 14, 2017): 2309–22. http://dx.doi.org/10.1177/0954405417697352.

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Computational fluid dynamics has been extensively used for fluid flow simulation and thus guiding the flow control device design. However, computational fluid dynamics simulation requires explicit geometry input and complicated solver setup, which is a barrier in case of the cyclic computer-aided design/computational fluid dynamics integrated design process. Tedious human interventions are inevitable to make up the gap. To fix this issue, this work proposed a theoretical framework where the computational fluid dynamics solver setup can be intelligently assisted by the simulation intent capture. Two feature concepts, the fluid physics feature and the dynamic physics feature, have been defined to support the simulation intent capture. A prototype has been developed for the computer-aided design/computational fluid dynamics integrated design implementation without the need of human intervention, where the design intent and computational fluid dynamics simulation intent are associated seamlessly. An outflow control device used in the steam-assisted gravity drainage process is studied using this prototype, and the target performance of the device is effectively optimized.

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S. Hussein, Suhad. "A Computer Simulation Study of High Pressure Processing of Liquid Food Using Computational Fluid Dynamics." International Journal of Modeling and Optimization 5, no. 1 (February 2015): 78–81. http://dx.doi.org/10.7763/ijmo.2015.v5.440.

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Wu, Enhua, Hongbin Zhu, Xuehui Liu, and Youquan Liu. "Simulation and interaction of fluid dynamics." Visual Computer 23, no. 5 (March 27, 2007): 299–308. http://dx.doi.org/10.1007/s00371-007-0106-y.

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Drikakis, Dimitris, Michael Frank, and Gavin Tabor. "Multiscale Computational Fluid Dynamics." Energies 12, no. 17 (August 25, 2019): 3272. http://dx.doi.org/10.3390/en12173272.

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Computational Fluid Dynamics (CFD) has numerous applications in the field of energy research, in modelling the basic physics of combustion, multiphase flow and heat transfer; and in the simulation of mechanical devices such as turbines, wind wave and tidal devices, and other devices for energy generation. With the constant increase in available computing power, the fidelity and accuracy of CFD simulations have constantly improved, and the technique is now an integral part of research and development. In the past few years, the development of multiscale methods has emerged as a topic of intensive research. The variable scales may be associated with scales of turbulence, or other physical processes which operate across a range of different scales, and often lead to spatial and temporal scales crossing the boundaries of continuum and molecular mechanics. In this paper, we present a short review of multiscale CFD frameworks with potential applications to energy problems.

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Schlijper, A. G., C. W. Manke, W. G. Madden, and Y. Kong. "Computer Simulation of Non-Newtonian Fluid Rheology." International Journal of Modern Physics C 08, no. 04 (August 1997): 919–29. http://dx.doi.org/10.1142/s0129183197000795.

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Dissipative Particle Dynamics (DPD) is a new simulation technique that focuses on intermediate time and length scales. With this technique it is possible to simulate the essential aspects of the rheological behavior of polymeric liquids quite efficiently. Model studies show that DPD reveals the expected shear thinning and normal stress effects. We also show that the effects of thermodynamic solvent quality on the configurations and rheological behavior of dissolved polymers can be studied with the DPD model.

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Kraváriková, Helena. "Computer Modeling Application of Fluid Outflow from Vessels." Materials Science Forum 952 (April 2019): 250–57. http://dx.doi.org/10.4028/www.scientific.net/msf.952.250.

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The aim of the paper is to evaluate numerical analysis of the fluid flow during the outflow from vessel orifices at various locations. The problems of the outflow velocities and pressure fields were well-chosen for the given purposes. The selected fluid flow problems were solved by numerical simulation using FEM in ANSYS. For numerical simulation, we used the basic steps to design an abstract model in the ANSYS virtual environment. Numerical simulation requires a geometric model complemented by physical properties of flowing fluids as well as both the initial and boundary conditions. It is then possible to calculate the velocity and pressure fields by numerical simulation for a particular fluid type. The results obtained from the numerical simulation were compared with those of the analytical solution. The results obtained from modeling and numerical simulation correspond to the actual values with minimum deviations. The demonstrated type of the problem solved by numerical simulation and modeling confirmed the advantages and possibilities of flexible solutions for any combination of problems in the field of fluid dynamics. Modeling and numerical simulation of fluid flow can provide results regarding the speed and the pressure fields in vessels and pipelines.

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AGISHTEIN, M. E., and A. A. MIGDAL. "COMPUTER SIMULATION OF THREE-DIMENSIONAL VORTEX DYNAMICS." Modern Physics Letters A 01, no. 03 (June 1986): 221–30. http://dx.doi.org/10.1142/s0217732386000312.

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The discrete model, approximating with exponential accuracy the set of interacting closed vortex lines in an ideal fluid, is proposed and investigated by means of the computer. The vortex lines move in their own velocity field according to the Biot-Savart law. This is a generalized Hamiltonian system possessing in addition an infinite number of conservation laws. Nevertheless, the motion becomes stochastic for certain initial conditions, and may be interpreted as marking the onset of turbulence.

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Zhu, Likuan, Boyan Song, and Zhen Long Wang. "Computational Fluid Dynamics Analysis on Rupture of Gas Bubble." Applied Mechanics and Materials 339 (July 2013): 468–73. http://dx.doi.org/10.4028/www.scientific.net/amm.339.468.

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Hydrodynamic information of the flow occurring as a bubble ruptures at a gas liquid interface has being obtained from computer simulations. The simulation result is verified by conducting high-speed photography experiment. Process of bubble rupture is clearly captured with simulation and experiment. Shear force generated by bubble rupture increases along with decrease of bursting bubble diameter or increase of coefficient of surface tension. The maximum average shear force ranges from 0.97Pa to 1.91Pa, when bursting bubble diameter changes from 2mm to 10mm.

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Leoveanu, Ioan Sorin, Kamila Kotrasova, and Eva Kormaníková. "Using of Computer Fluid Dynamics in Simulation of the Waste Reserviors Processes." Advanced Materials Research 969 (June 2014): 351–54. http://dx.doi.org/10.4028/www.scientific.net/amr.969.351.

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The paper scope consists in using the computational fluid dynamics for the simulation of waste reservoirs processes like the flood filling regime, flow over the dam in flood filling, and earthquake disaster. The flood regime may induce a particularly dynamics pressure on the dam walls and a particularly distribution of fluid flow inside liquid. On the other hand, when the disaster like earthquake occurs, the fluid dynamics and the induced pressures on the dam walls become extremely important for safety estimation of critical components. The dam break case is extremely important in management of safety buildings in the neighboring area of the reservoirs too. Solutions of these important civil engineering problems were obtained using the classical Navier-Stokes fluid flow equations. In the analyzed cases, the simulations were based for solving the problem of fluid with the free surface flow and complex boundary configurations by using an original program developed with MAC method.

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Umbarkar, Tejas S., and Clement Kleinstreuer. "Computationally Efficient Fluid-Particle Dynamics Simulations of Arterial Systems." Communications in Computational Physics 17, no. 2 (January 23, 2015): 401–23. http://dx.doi.org/10.4208/cicp.160114.120914a.

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AbstractRealistic and accurate computer simulations of the particle-hemodynamics in arterial systems can be a valuable tool for numerous biomedical applications. Examples include optimal by-pass grafting and optimal drug-delivery, as well as best medical management concerning the cardio-vascular system. However, such numerical analyses require large computer resources which may become prohibitive for extended sets of arterial bifurcations. A remedy is to develop a hybrid model where the first few generations of the bifurcating arteries of interest are simulated in full 3-D, while a 1-D model is then coupled for subsequent bifurcations. Alternatively, a 1-D computer model can be directly employed to simulate fluid-particle transport in complex bifurcating networks.Relying on a representative axial velocity profile, a physiological 1-D model has been developed and validated, which is capable of predicting with reasonable accuracy arterial flow, pressure field and elastic wall interaction as well as particle transport. The usefulness of the novel 1-D simulation approach is demonstrated via a comparison to 3-D blood flow and microsphere transport in a hepatic artery system, featuring as outlets one major branch and four small daughter vessels. Compared to the 3-D simulation, the 1-D analysis requires only about 1% of computational time. The hybrid modeling approach would be also applicable to the human respiratory tract to evaluate the fate of inhaled aerosols.A simple and cost-effective way to simulate particle-hemodynamics is using a 1-D model for simulating arterial pressures and flow rates as well as microsphere transport, based on assumptions involving the use of a simple algebraic pressure-area relation, an exponential elasticity model for the vessels, and considering only unidirectional flow with a representative skewed velocity profile. In summary, the novel contributions are:• Particle tracking in arteries via 1-D fluid modeling and selection of an averaged, skewed velocity profile based on 3-D simulation results to provide more realistic friction and inertia term values for modeling a flow system with bifurcations.• The 1-D model can be coupled to a 3-D model so that simulations can be run for larger regions of vascular or lung-airway systems.

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Sandrakov, G. V. "COMPUTATIONAL ALGORITHMS FOR MULTIPHASE HYDRODYNAMICS MODELS AND FILTRATION." Journal of Numerical and Applied Mathematics, no. 1 (2022): 46–61. http://dx.doi.org/10.17721/2706-9699.2022.1.04.

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Computational algorithms for modeling of multiphase hydrodynamics processes with take of phase transitions will be discussed. The algorithms are based on discretization of conservation laws for mass, momentum, and energy in integral and differential forms. The time and spatial discretization is natural and numerical simulations are realized as direct computer experiments. The experiments are implemented as a computer simulation of the dynamics of a multiphase carrier fluid containing particles that can undergo, for example, graphite–diamond phase transitions and calculations are given. Modification of the algorithms have also been developed to take into account the influence of viscosity when simulating the dynamics of a multiphase fluid in porous media.

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Wang, Xiaokun, Yanrui Xu, Xiaojuan Ban, Sinuo Liu, and Yuting Xu. "A Unified Multiple-Phase Fluids Framework Using Asymmetric Surface Extraction and the Modified Density Model." Symmetry 11, no. 6 (June 2, 2019): 745. http://dx.doi.org/10.3390/sym11060745.

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Multiple-phase fluids’ simulation and 3D visualization comprise an important cooperative visualization subject between fluid dynamics and computer animation. Interactions between different fluids have been widely studied in both physics and computer graphics. To further the study in both areas, cooperative research has been carried out; hence, a more authentic fluid simulation method is required. The key to a better multiphase fluid simulation result is surface extraction. Previous works usually have problems in extracting surfaces with unnatural fluctuations or detail missing. Gaps between different phases also hinder the reality of simulation. In this paper, we propose a unified surface extraction approach integrated with a modified density model for the particle-based multiphase fluid simulation. We refine the original asymmetric smoothing kernel used in the color field and address a binary tree scheme for surface extraction. Besides, we employ a multiphase fluid framework with modified density to eliminate density deviation between different fluids. With the methods mentioned above, our approach can effectively reconstruct the fluid surface for particle-based multiphase fluid simulation. It can also resolve the issue of overlaps and gaps between different fluids, which has widely existed in former methods for a long time. The experiments carried out in this paper show that our approach is able to have an ideal fluid surface condition and have good interaction effects.

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Nagaso, Masaru, Joseph Moysan, Christian Lhuillier, and Jean-Philippe Jeannot. "Simulation of Fluid Dynamics Monitoring Using Ultrasonic Measurements." Applied Sciences 11, no. 15 (July 30, 2021): 7065. http://dx.doi.org/10.3390/app11157065.

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The simulation of the propagation of ultrasonic waves in a moving fluid will improve the efficiency of the ultrasonic flow monitoring and that of the in-service monitoring for various reactors in several industries. The most recent simulations are mostly limited to 3D representations of the insonified volume but without really considering the temporal aspect of the flow. The advent of high-performance computing (HPC) now makes it possible to propose the first 4D simulations, with the representation of the inspected medium evolving over time. This work is based on a highly accurate double simulation. A first computational fluid dynamics (CFD) simulation, performed in previous work, described the fluid medium resulting from the mixing of hot jets in a cold opaque fluid. There have been many sensor developments over the years in this domain, as ultrasounds are the only method able to give information in an opaque medium. The correct design of these sensors, as well as the precise and confident analysis of their measurements, will progress with the development of the modeling of wave propagation in such a medium. An important parameter to consider is the flow temperature description, as a temperature gradient in the medium deflects the wave path and may sometimes cause its division. We develop a 4D wave propagation simulation in a very realistic, temporally fluctuating medium. A high-performance simulation is proposed in this work to include an ultrasonic source within the medium and to calculate the wave propagation between a transmitter and a receiver. The analysis of the wave variations shows that this through-transmission setup can track the jet mixing time variations. The steps needed to achieve these results are described using the spectral-element-based numerical tool SPECFEM3D. It is shown that the low-frequency fluctuation of the liquid metal flow can be observed using ultrasonic measurements.

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Mannan, Mohammed Abdul, and Dr Md Fakhruddin H. N. "Computational Fluid Dynamics in Coronary and Intra-Cardiac Flow Simulation." International Journal for Research in Applied Science and Engineering Technology 10, no. 7 (July 31, 2022): 688–93. http://dx.doi.org/10.22214/ijraset.2022.45280.

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Abstract: Computational fluid dynamics (CFD) is a field of mechanical engineering for the analysis of fluid flows, heat transfer, and related phenomena, using computer simulations. CFD is a widely adopted methodology for solving complex problems in many areas of modern engineering. The merits of CFD are the development of new and improved equipment and system designs, and optimizations are performed on existing equipment through simulation, leading to increased efficiency and reduced costs. However, in the biomedical sector, CFD are still emerging. The main reason why CFD in the biomedical field lags behind is the enormous complexity in the workings of human body fluids. Recently, biomedical CFD research has become more accessible as high-performance hardware and software are readily available because of advances in computing. Every CFD process contains three main components that provide useful information, Pre-processing, formula resolution, and post-processing. Precise initial boundary conditions and geometric models are essential to obtain appropriate results. Medical imaging, like ultrasound imaging, computerized tomography, and resonance imaging can be used for modeling, and Doppler ultrasound, manometers, and noninvasive manometers are used for flow velocity and pressure as boundary conditions.

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Anderson, Richard L., H. Christopher Greenwel, James L. Suter, Rebecca M. Jarvis, and Peter V. Coveney. "Towards the design of new and improved drilling fluid additives using molecular dynamics simulations." Anais da Academia Brasileira de Ciências 82, no. 1 (March 2010): 43–60. http://dx.doi.org/10.1590/s0001-37652010000100005.

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During exploration for oil and gas, a technical drilling fluid is used to lubricate the drill bit, maintain hydrostatic pressure, transmit sensor readings, remove rock cuttings and inhibit swelling of unstable clay based reactive shale formations. Increasing environmental awareness and resulting legislation has led to the search for new, improved biodegradable drilling fluid components. In the case of additives for clay swelling inhibition, an understanding of how existing effective additives interact with clays must be gained to allow the design of improved molecules. Owing to the disordered nature and nanoscopic dimension of the interlayer pores of clay minerals, computer simulations have become an increasingly useful tool for studying clay-swelling inhibitor interactions. In this work we briefly review the history of the development of technical drilling fluids, the environmental impact of drilling fluids and the use of computer simulations to study the interactions between clay minerals and swelling inhibitors. We report on results from some recent large-scale molecular dynamics simulation studies on low molecular weight water-soluble macromolecular inhibitor molecules. The structure and interactions of poly(propylene oxide)-diamine, poly(ethylene glycol) and poly(ethylene oxide)-diacrylate inhibitor molecules with montmorillonite clay are studied.

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Wu, S. Z., D. N. Wormley, D. Rowell, and H. M. Paynter. "Dynamic Modeling and Simulation of Gaseous Systems." Journal of Dynamic Systems, Measurement, and Control 107, no. 4 (December 1, 1985): 262–66. http://dx.doi.org/10.1115/1.3140733.

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A general computer-based mathematical modeling system for analyzing air/gas system dynamics has been developed. A set of generic lumped and distributed elements are interconnected by generalized junction structures to represent system configurations. The dynamic response of pressure, flow, temperature, and heat transfer rate at any point in a system, due to control actions, or fluid, thermal, or mechanical disturbances can be determined. The model has been used to analyze furnace implosion and disturbance propagation problems in fossil fuel power plants. To illustrate the modeling techniques, a model of a coal-fired plant has been constructed and pressure transients computed following a fuel trip. The model simulation predictions of the furnace pressure excursions are in close agreement with the data from field tests.

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Heryana, Yayan Heryana. "Analysis of Orifice in Biodiesel Reactor with Hydrodynamic Cavitation System using Computational Fluid Dynamics." Jurnal Keteknikan Pertanian 10, no. 1 (May 18, 2022): 85–94. http://dx.doi.org/10.19028/jtep.010.1.85-94.

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Reactor technology for the transesterification process of vegetable oils or animal fats with methanol has been widely developed to obtain biodiesel products that comply with standards but at the lowest cost. The hydrodynamic cavitation reactor with orifice type is a choice for this purpose. This research aims to determine the optimal orifice design from several orifice designs tested through CFD simulation. Computer simulations performed on orifices A, B, C and D using the Schnerr and Sauer models show that orifice C is optimal for cavitation at an absolute inlet pressure of 3x105 N/m2 with the use of methanol as fluid. The parameters studied in the computer simulation are velocity, pressure, turbulent kinetic energy and vapor volume fraction. At the absolute inlet pressure of 3x105 N/m2, the maximum speed is 28.69 m/s, the minimum pressure is 12266 N/m2, the maximum vapor volume fraction is 0.98, and the maximum turbulent kinetic energy is 12.75 m2/s2. The results of simulation were compared with experiments conducted on a hydrodynamic cavitation reactor using orifices C and D. Measurements of the velocity and pressure parameters showed that there were no significant deviations between the results of the computer simulation and the experiment.

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Yao, Yao, Yu Bai, and Ming Liu. "Fluid Dynamics Analysis and Research of Electrostatic Oiler Knife Beam." Applied Mechanics and Materials 318 (May 2013): 140–43. http://dx.doi.org/10.4028/www.scientific.net/amm.318.140.

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The research object of this paper is about the oil equipments’ fluid properties during spraying of the electrostatic spraying technology. Establishing the mathematical model of fluid inside the oiling machine in the process of computer simulation and using fluid dynamics analysis software ( CFD ) FLUENT to analyse numerical simulation within spraying fluid effectively. According to the actual situation, reach knife beam’s pressure distribution, velocity distribution, flow trajectories, partial velocity diagram. Finally, verify the correctness and feasibility of the simulation by the contrast of the experimental and simulation data in the course of experiments. In view of the analysis and study of the electrostatic oiler internal fluid, it can be extended to the electrostatic spraying technology. The paper is supplement for further research of electrostatic spraying technology and data support for next step simulation analysis of loading of high-voltage electric field.

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Huang, Hanyao, Xu Cheng, Yang Wang, Dantong Huang, Yuhao Wei, Heng Yin, Bing Shi, and Jingtao Li. "Analysis of Velopharyngeal Functions Using Computational Fluid Dynamics Simulations." Annals of Otology, Rhinology & Laryngology 128, no. 8 (April 8, 2019): 742–48. http://dx.doi.org/10.1177/0003489419842217.

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Objectives: Competent velopharyngeal (VP) function is the basis for normal speech. Understanding how VP structure influences the airflow during speech details is essential to the surgical improvement of pharyngoplasty. In this study, we aimed to illuminate the airflow features corresponding to various VP closure states using computed dynamic simulations. Methods: Three-dimensional models of the upper airways were established based on computed tomography of 8 volunteers. The velopharyngeal port was simulated by a cylinder. Computational fluid dynamics simulations were applied to illustrate the correlation between the VP port size and the airflow parameters, including the flow velocity, pressure in the velopharyngeal port, as well as the pressure in oral and nasal cavity. Results: The airflow dynamics at the velopharynx were maintained in the same velopharyngeal pattern as the area of the velopharyngeal port increased from 0 to 25 mm2. A total of 5 airflow patterns with distinct features were captured, corresponding to adequate closure, adequate/borderline closure (Class I and II), borderline/inadequate closure, and inadequate closure. The maximal orifice area that could be tolerated for adequate VP closure was determined to be 2.01 mm2. Conclusion: Different VP functions are of characteristic airflow dynamic features. Computational fluid dynamic simulation is of application potential in individualized VP surgery planning.

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Raczkowski, Andrzej, Zbigniew Suchorab, and Przemysław Brzyski. "Computational fluid dynamics simulation of thermal comfort in naturally ventilated room." MATEC Web of Conferences 252 (2019): 04007. http://dx.doi.org/10.1051/matecconf/201925204007.

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The paper presents experimental measurements and numerical simulation of thermal environment in naturally ventilated room by a fresh air valve. For the aim of Computer Fluid Dynamics (CFD) simulations, a model room was created. The fresh air valve is located in an occupied space, at the external wall. It has a major effect on mixing indoor and outdoor air, temperature profiles, thermal condition and indoor air quality of the rooms during the heating period. To determine the thermal condition of a naturally ventilated building, PN-EN 15251:2012 standard was used. According to the standard, using PMV/PPD is suitable for evaluating the thermal environment. In the naturally ventilated buildings, the following criteria are very important for local thermal discomfort: draught, radiant temperature asymmetry and vertical air temperature differences. To compare the simulation results, real air temperatures were measured by the thermocouples in a day room having the same geometry. A series of simulations has been carried out to determine the profiles of temperature and velocity of indoor air. Obtained results prove correlation with calculations of profiles of indoor air temperature, estimated using the thermocouples.

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Janczarek, Marcin, and Ewa Kowalska. "Computer Simulations of Photocatalytic Reactors." Catalysts 11, no. 2 (February 3, 2021): 198. http://dx.doi.org/10.3390/catal11020198.

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Photocatalysis has been considered future technology for green energy conversion and environmental purification, including carbon dioxide reduction, water splitting, air/water treatment, and antimicrobial purposes. Although various photocatalysts with high activity and stability have already been found, the commercialization of photocatalytic processes seems to be slow; it is thought that the difficulty in scaling up photocatalytic processes might be responsible. Research on the design of photocatalytic reactors using computer simulations has been recently intensive. The computer simulations involve various methods of hydrodynamics, radiation, and mass transport analysis, including the Monte Carlo method, the approximation approach–P1 model, and computational fluid dynamics as a complex simulation tool. This review presents all of these models, which might be efficiently used for the scaling-up of photocatalytic reactors. The challenging aspects and perspectives of computer simulation are also addressed for the future development of applied photocatalysis.

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Yamagata, Kanako, Keiji Shinozuka, Shouhei Ogisawa, Akio Himejima, Hiroaki Azaki, Shuichi Nishikubo, Takako Sato, Masaaki Suzuki, Tadashi Tanuma, and Morio Tonogi. "A preoperative predictive study of advantages of airway changes after maxillomandibular advancement surgery using computational fluid dynamics analysis." PLOS ONE 16, no. 8 (August 11, 2021): e0255973. http://dx.doi.org/10.1371/journal.pone.0255973.

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The purpose of this study was to develop a simulation approach for predicting maxillomandibular advancement-induced airway changes using computational fluid dynamics. Eight patients with jaw deformities who underwent maxillomandibular advancement and genioglossus advancement surgery were included in this study. Computed tomography scans and rhinomanometric readings were performed both preoperatively and postoperatively. Computational fluid dynamics models were created, and airflow simulations were performed using computational fluid dynamics software; the preferable number of computational mesh points was at least 10 million cells. The results for the right and left nares, including simulation and postoperative measurements, were qualitatively consistent, and surgery reduced airflow pressure loss. Geometry prediction simulation results were qualitatively consistent with the postoperative stereolithography data and postoperative simulation results. Simulations were performed with either the right or left naris blocked, and the predicted values were similar to those found clinically. In addition, geometry prediction simulation results were qualitatively consistent with the postoperative stereolithography data and postoperative simulation results. These findings suggest that geometry prediction simulation facilitates the preoperative prediction of the postoperative structural outcome.

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Berger, Manuel, Aris I. Giotakis, Martin Pillei, Andreas Mehrle, Michael Kraxner, Florian Kral, Wolfgang Recheis, Herbert Riechelmann, and Wolfgang Freysinger. "Agreement between rhinomanometry and computed tomography-based computational fluid dynamics." International Journal of Computer Assisted Radiology and Surgery 16, no. 4 (March 7, 2021): 629–38. http://dx.doi.org/10.1007/s11548-021-02332-1.

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Abstract Purpose Active anterior rhinomanometry (AAR) and computed tomography (CT) are standardized methods for the evaluation of nasal obstruction. Recent attempts to correlate AAR with CT-based computational fluid dynamics (CFD) have been controversial. We aimed to investigate this correlation and agreement based on an in-house developed procedure. Methods In a pilot study, we retrospectively examined five subjects scheduled for septoplasty, along with preoperative digital volume tomography and AAR. The simulation was performed with Sailfish CFD, a lattice Boltzmann code. We examined the correlation and agreement of pressure derived from AAR (RhinoPress) and simulation (SimPress) and these of resistance during inspiration by 150 Pa pressure drop derived from AAR (RhinoRes150) and simulation (SimRes150). For investigation of correlation between pressures and between resistances, a univariate analysis of variance and a Pearson’s correlation were performed, respectively. For investigation of agreement, the Bland–Altman method was used. Results The correlation coefficient between RhinoPress and SimPress was r = 0.93 (p < 0.001). RhinoPress was similar to SimPress in the less obstructed nasal side and two times greater than SimPress in the more obstructed nasal side. A moderate correlation was found between RhinoRes150 and SimRes150 (r = 0.65; p = 0.041). Conclusion The simulation of rhinomanometry pressure by CT-based CFD seems more feasible with the lattice Boltzmann code in the less obstructed nasal side. In the more obstructed nasal side, error rates of up to 100% were encountered. Our results imply that the pressure and resistance derived from CT-based CFD and AAR were similar, yet not same.

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Wretborn, Joel, Sean Flynn, and Alexey Stomakhin. "Guided bubbles and wet foam for realistic whitewater simulation." ACM Transactions on Graphics 41, no. 4 (July 2022): 1–16. http://dx.doi.org/10.1145/3528223.3530059.

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We present a method for enhancing fluid simulations with realistic bubble and foam detail. We treat bubbles as discrete air particles, two-way coupled with a sparse volumetric Euler flow, as first suggested in [Stomakhin et al. 2020]. We elaborate further on their scheme and introduce a bubble inertia correction term for improved convergence. We also show how one can add bubbles to an already existing fluid simulation using our novel guiding technique, which performs local re-simulation of fluid to achieve more interesting bubble dynamics through coupling. As bubbles reach the surface, they are converted into foam and simulated separately. Our foam is discretized with smoothed particle hydrodynamics (SPH), and we replace forces normal to the fluid surface with a fluid surface manifold advection constraint to achieve more robust and stable results. The SPH forces are derived through proper constitutive modeling of an incompressible viscous liquid, and we explain why this choice is appropriate for "wet" types of foam. This allows us to produce believable dynamics from close-up scenarios to large oceans, with just a few parameters that work intuitively across a variety of scales. Additionally, we present relevant research on air entrainment metrics and bubble distributions that have been used in this work.

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Shao, Xuqiang, Erchong Liao, and Fengquan Zhang. "Improving SPH Fluid Simulation Using Position Based Dynamics." IEEE Access 5 (2017): 13901–8. http://dx.doi.org/10.1109/access.2017.2729601.

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Shinto, Hiroyuki. "Computer Simulation of Wetting and Capillary Forces —Molecular Modeling and Fluid Dynamics—." Journal of the Society of Powder Technology, Japan 46, no. 1 (January 10, 2009): 25–34. http://dx.doi.org/10.4164/sptj.46.25.

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Kinjo, T., K. Ohguchi, K. Yasuoka, and M. Matsumoto. "Computer simulation of fluid phase change: vapor nucleation and bubble formation dynamics." Computational Materials Science 14, no. 1-4 (February 1999): 138–41. http://dx.doi.org/10.1016/s0927-0256(98)00088-3.

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Araújo, Bruna Sene Alves, and Kássia Graciele dos Santos. "CFD Simulation of Different Flow Regimes of the Spout Fluidized Bed with Draft Plates." Materials Science Forum 899 (July 2017): 89–94. http://dx.doi.org/10.4028/www.scientific.net/msf.899.89.

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Spout fluidized bed has shown promising for gas-solid contact operations with and without chemical reactions, such as drying, coating, granulation, gasification, pyrolysis, etc. This is because these beds combine features from both spouted and fluidized beds. The other point is the ability to treat chemical transformations involving both heat and mass transfer in combination with particles of various sizes. Therefore, it is extremely important the knowledge of fluid dynamic of the bed, mainly for scale-up projects, which makes computer simulation an essential tool. Researches using the Computation Fluid Dynamics (CFD) proved to be very effective in predicting of particles dynamic in this type of bed. In Computation Fluid Dynamics, the two phases are treated as interpenetration continuous, and these phases are described by equations of conservation of mass, momentum and energy. The goal of the present work was to simulate using CFD experimental fluid dynamics data of a spout fluidized bed. Eight distinct flow regimes were identified which showed up in good agreement with the regime map presented in literature. The results showed that the technique was efficient for the simulation of the hydrodynamic of the bed presented.

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Yu, Zhenning, and Seng Fat Wong. "The application of computational fluid dynamics simulation technique to ocean boat anti-disturbance tracking controller." International Journal of Advanced Robotic Systems 16, no. 3 (May 1, 2019): 172988141984204. http://dx.doi.org/10.1177/1729881419842045.

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This article presents the verification problem of estimating boat hull damping parameters using the computational fluid dynamics technique. In addition, a Lyapunov-based path control system will be introduced to centify the estimation result. The controller should satisfy the following features: firstly, maintaining that the boat dynamic model which includes path, velocity, and orientation errors are asymptotically stable; secondly, ensuring the actuation is operating normally under the nonlinear hydrodynamic system and actual environment limitation; thirdly, working with the anti-disturbance algorithm which includes a projection update law. The final part of the article introduces the procedure proving that the computational fluid dynamics simulation result and Lyapunov direct method controller are acceptable for the ocean boat nonlinear dynamic system. It is confirmed that the control system simulation can improve computational fluid dynamics technology instead of an actual experiment. It can solve the estimation problem caused by limitations in equipment or funds.

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Dixon, Anthony G., and Behnam Partopour. "Computational Fluid Dynamics for Fixed Bed Reactor Design." Annual Review of Chemical and Biomolecular Engineering 11, no. 1 (June 7, 2020): 109–30. http://dx.doi.org/10.1146/annurev-chembioeng-092319-075328.

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Flow, heat, and mass transfer in fixed beds of catalyst particles are complex phenomena and, when combined with catalytic reactions, are multiscale in both time and space; therefore, advanced computational techniques are being applied to fixed bed modeling to an ever-greater extent. The fast-growing literature on the use of computational fluid dynamics (CFD) in fixed bed design reflects the rapid development of this subfield of reactor modeling. We identify recent trends and research directions in which successful methodology has been established, for example, in computer generation of packings of complex particles, and where more work is needed, for example, in the meshing of nonsphere packings and the simulation of industrial-size packed tubes. Development of fixed bed reactor models, by either using CFD directly or obtaining insight, closures, and parameters for engineering models from simulations, will increase confidence in using these methods for design along with, or instead of, expensive pilot-scale experiments.

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Filipovic, Nenad, and Milos Kojic. "Computer simulations of blood flow with mass transport through the carotid artery bifurcation." Theoretical and Applied Mechanics 31, no. 1 (2004): 1–33. http://dx.doi.org/10.2298/tam0401001f.

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The current paradigm for clinical diagnostic for the treatment of vascular disease relies exclusively on diagnostic imaging data to define the present state of the patient, empirical data to evaluate the efficacy of prior treatments for similar patients. These techniques are insufficient to predict the outcome of a given treatment for an individual patient. We here propose a new paradigm of predictive medicine where physician could use computational simulation to construct and evaluate a specific geometrical/anatomical model to predict the outcome for an individual patient. For this purpose it is necessary to develop a complex software system which combines user friendly interface, automatic solid modeling, automatic finite mesh generation, computational fluid dynamics and post-processing visualization. The flow dynamics is defined according to the incompressible Navier-Stokes equations for Newtonian and non-Newtonian fluids. Mass transport of oxygen and macromolecules is modeled by the convection diffusion equation and coupled with flow dynamics. The computer simulations are based upon finite element analysis where the new computer methods for coupling oxygen transport and fluid flow are described. The comparison results shows a good agreement between clinical observation for critical zones of flow separation, flow recirculation, low wall shear stresses which may contribute to the development of atherosclerotic diseases.

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Šulc, Stanislav, Vít Šmilauer, and František Wald. "COUPLED SIMULATION FOR FIRE-EXPOSED STRUCTURES USING CFD AND THERMO-MECHANICAL MODELS." Acta Polytechnica CTU Proceedings 13 (November 13, 2017): 121. http://dx.doi.org/10.14311/app.2017.13.0121.

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Fire resistance of buildings is based on fire tests in furnaces with gas burners. However, the tests are very expensive and time consuming. This article presents a coupled simulation of an element loaded by a force and a fire loading. The simulation solves a weakly-coupled problem, consisting of fluid dynamics, heat transfer and mechanical model. The temperature field from the computational fluid dynamics simulation (CFD) creates Cauchy and radiative boundary conditions for the thermal model. Then, the temperature field from element is passed to the mechanical model, which induces thermal strain and modifies material parameters. The fluid dynamics is computed with Fire Dynamics Simulator and the thermo-mechanical task is solved in OOFEM. Both softwares are interconnected with MuPIF python library, which allows smooth data transfer across the different meshes, orchestrating simulations in particular codes, exporting results to the VTK formats and distributed computing.

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Skipper, N. T. "Computer simulation of aqueous pore fluids in 2:1 clay minerals." Mineralogical Magazine 62, no. 5 (October 1998): 657–67. http://dx.doi.org/10.1180/002646198548043.

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AbstractMonte Carlo and molecular dynamics computer simulations are now able to provide detailed information concerning the structure, dynamics, and thermodynamics of pore fluids in 2:1 clays. This article will discuss interparticle interaction potentials currently available for atomistic simulations of clay-water systems, and will describe how computational techniques can be applied to modelling of clay systems. Some recent simulation studies of 2:1 clay hydration will then be reviewed. Comparison with experimental data promotes confidence in the molecular models and simulation techniques, and points to exciting future prospects.

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MOEENDARBARY, E., T. Y. NG, and M. ZANGENEH. "DISSIPATIVE PARTICLE DYNAMICS IN SOFT MATTER AND POLYMERIC APPLICATIONS — A REVIEW." International Journal of Applied Mechanics 02, no. 01 (March 2010): 161–90. http://dx.doi.org/10.1142/s1758825110000469.

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Computer simulations and in particular mesoscopic simulation techniques such as the dissipative particle dynamics (DPD) technique, enable researchers to study the complexities of soft material and polymeric systems by performing in silico experimentations alongside in vivo experiments. In addition, these mesoscopic simulations allow scientists and engineers to characterize and optimize the actual experiments in a more efficient manner. The DPD is one the most reliable mesoscopic simulation techniques for phenomenological investigation of soft matter and polymeric systems. In this review, which is complimentary to an earlier review also by the present authors on DPD methodology and complex fluid application (Moeendarbary et al., 2009), we categorize and review the notable published works, and document efforts that applied the DPD simulation technique to various important soft matter and polymeric applications, over the last decade.

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Marturano, Fabio, Luca Martellucci, Andrea Chierici, Andrea Malizia, Daniele Di Giovanni, Francesco d’Errico, Pasquale Gaudio, and Jean-Franҫois Ciparisse. "Numerical Fluid Dynamics Simulation for Drones’ Chemical Detection." Drones 5, no. 3 (July 29, 2021): 69. http://dx.doi.org/10.3390/drones5030069.

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The risk associated with chemical, biological, radiological, nuclear, and explosive (CBRNe) threats in the last two decades has grown as a result of easier access to hazardous materials and agents, potentially increasing the chance for dangerous events. Consequently, early detection of a threat following a CBRNe event is a mandatory requirement for the safety and security of human operators involved in the management of the emergency. Drones are nowadays one of the most advanced and versatile tools available, and they have proven to be successfully used in many different application fields. The use of drones equipped with inexpensive and selective detectors could be both a solution to improve the early detection of threats and, at the same time, a solution for human operators to prevent dangerous situations. To maximize the drone’s capability of detecting dangerous volatile substances, fluid dynamics numerical simulations may be used to understand the optimal configuration of the detectors positioned on the drone. This study serves as a first step to investigate how the fluid dynamics of the drone propeller flow and the different sensors position on-board could affect the conditioning and acquisition of data. The first consequence of this approach may lead to optimizing the position of the detectors on the drone based not only on the specific technology of the sensor, but also on the type of chemical agent dispersed in the environment, eventually allowing to define a technological solution to enhance the detection process and ensure the safety and security of first responders.

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BARTOLONI, A., C. BATTISTA, S. CABASINO, P. S. PAOLUCCI, J. PECH, R. SARNO, G. M. TODESCO, et al. "LBE SIMULATIONS OF RAYLEIGH-BÉNARD CONVECTION ON THE APE100 PARALLEL PROCESSOR." International Journal of Modern Physics C 04, no. 05 (October 1993): 993–1006. http://dx.doi.org/10.1142/s012918319300077x.

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In this paper we describe an implementation of the Lattice Boltzmann Equation method for fluid-dynamics simulations on the APE100 parallel computer. We have performed a simulation of a two-dimensional Rayleigh-Bénard convection cell. We have tested the theory proposed by Shraiman and Siggia for the scaling of the Nusselt number vs. Rayleigh number.

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Sun, Jin, Francine Battaglia, and Shankar Subramaniam. "Hybrid Two-Fluid DEM Simulation of Gas-Solid Fluidized Beds." Journal of Fluids Engineering 129, no. 11 (June 9, 2007): 1394–403. http://dx.doi.org/10.1115/1.2786530.

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Simulations of gas-solid fluidized beds have been performed using a hybrid simulation method, which couples the discrete element method (DEM) for particle dynamics with the averaged two-fluid (TF) continuum equations for the gas phase. The coupling between the two phases is modeled using an interphase momentum transfer term. The results of the hybrid TF-DEM simulations are compared to experimental data and TF model simulations. It is found that the TF-DEM simulation is capable of predicting general fluidized bed dynamics, i.e., pressure drop across the bed and bed expansion, which are in agreement with experimental measurements and TF model predictions. Multiparticle contacts and large contact forces distribute in the regions away from bubbles, as demonstrated from the TF-DEM simulation results. The TF-DEM model demonstrates the capability to capture more heterogeneous structural information of the fluidized beds than the TF model alone. The implications to the solid phase constitutive closures for TF models are discussed. However, the TF-DEM simulations depend on the form of the interphase momentum transfer model, which can be computed in terms of averaged or instantaneous particle quantities. Various forms of the interphase momentum transfer model are examined, and simulation results from these models are compared.

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Carvalho, A. J. G., D. C. Galindo, M. S. C. Tenório, and J. L. G. Marinho. "MODELING AND SIMULATION OF A HORIZONTAL THREE-PHASE SEPARATOR: INFLUENCE OF PHYSICOCHEMICAL PROPERTIES OF OIL." Brazilian Journal of Petroleum and Gas 14, no. 04 (January 7, 2021): 205–20. http://dx.doi.org/10.5419/bjpg2020-0016.

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Fluids produced from oil reservoirs typically contain oil, natural gas, water, sediments, in varying amounts, and contaminating gases. Considering that economic interest usually targets mostly oil and gas, primary processing is used to separate water/oil/gas, in addition to treating these phases. Therefore, the well stream should be processed as soon as possible after reaching the surface. Separator vessels are among the main equipment used at surface production facilities, being responsible for the separation of the produced phases. This work focuses on studying the fluid dynamic behavior in a horizontal three-phase separator. To accomplish this goal, we used the computer fluid dynamics software ANSYS CFX. First, we performed a detailed analysis of a “Standard Case” to understand in detail the entire separation process within the vessel. The results show the three phases through the simulation time, analyses of the separation efficiency, different fluids flow lines, pressure gradient inside the vessel, and effect of the diverter baffle. It also considers a variation of fluid flow at the inlet of the separator. These analyses include pictures of all cases studied. Afterwards, some parameters of the standard case were altered to evaluate its influence on fluid dynamics behavior and the functioning of the separator vessel. At last, we analyzed the influences of oil density and viscosity on the separation. The oil quality affects the primary separation directly, as the oil density and viscosity increase, for example, increases the drag between the fluids and decreases the rate of sedimentation, which stickles the separation process difficult. Two out of the three cases generated satisfactory results. The simulation with the heaviest oil presented the worse results.

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Zou, Ling. "Simulating Liquid Dynamics by a Particle-Based Method." Applied Mechanics and Materials 380-384 (August 2013): 1121–24. http://dx.doi.org/10.4028/www.scientific.net/amm.380-384.1121.

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There is much research focusing on natural phenomena simulation in virtual reality and computer graphics. Liquid is chosen as our research object, because it is one of the most common natural phenomena. A particle-based modeling method for dynamic liquid simulation is presented in this paper. In our approach, accurate solutions for the Navier-Stokes equations are first accomplished in an Euler-based grid at each time step. This returns a velocity field calculated based on the pressure solved from a converted Poisson equation. Finally, particle movements are advected through this velocity field in order to simulate the dynamics of fluid volume. Experiment shows that visual effect which can satisfy users requirement is achieved by this method. This application has promising potentials in the areas of movie making, computer games, virtual construction and virtual simulation in medicine, etc.

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Bai, Ming Hua, Qing Rong Liu, and Hong Liang Zhou. "Design of Magnetic Fluid Sealing Device and Computer Simulation in Sintering Machine." Advanced Materials Research 328-330 (September 2011): 2270–73. http://dx.doi.org/10.4028/www.scientific.net/amr.328-330.2270.

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This paper, based on magnetic fluid dynamics, combined with the air leakage of sintering machine, proposes a new type of magnetic fluid sealing device in sintering machine. According to the sealing mechanism of MHD as well as Bernoulli equation, the sealing theory--pressure difference equation in static sealing by magnetic fluid is deduced for the actual model of sintering machine. By using ansys finite element simulation software, the two-dimensional numerical simulation of thermal magnetic- coupling inside of sealing device is set up, the effects of different temperature on the magnetic properties are analyzed and the best sealing performance is found, that is when the edge temperature of the sealing device is controlled from 30°C to 80°C.

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Wagner, Martin, and Marisol Ripoll. "Solvent-induced depletion interactions in multiparticle collision dynamic simulations." International Journal of Modern Physics C 30, no. 10 (October 2019): 1941008. http://dx.doi.org/10.1142/s0129183119410080.

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Molecular-dynamics-coupled multiparticle collision dynamic (MPC-MD) simulations have emerged to be an efficient and versatile tool in the description of mesoscale colloidal dynamics. However, the compressibility of the coarse-grained fluid leads to this method being prone to spurious depletion interactions that may dominate the colloidal dynamics. In this paper, we review the existing methodology to deal with these interactions, establish and report depletion measurements, and present a method to avoid artificial depletion in mesoscale simulation methods.

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SARMENTO, C. V. S., A. O. C. FONTE, L. J. PEDROSO, and P. M. V. RIBEIRO. "From numerical prototypes to real models: a progressive study of aerodynamic parameters of nonconventional concrete structures with Computational Fluid Dynamics." Revista IBRACON de Estruturas e Materiais 13, no. 3 (June 2020): 628–43. http://dx.doi.org/10.1590/s1983-41952020000300012.

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Abstract The practical evaluation of aerodynamic coefficients in unconventional concrete structures requires specific studies, which are small-scale models evaluated in wind tunnels. Sophisticated facilities and special sensors are needed, and the tendency is for modern and slender constructions to arise with specific demands on their interaction with the wind. On the other hand, the advances obtained in modern multi-core processors emerge as an alternative for the construction of sophisticated computational models, where the Navier-Stokes differential equations are solved for fluid flow using numerical methods. Computations of this kind require specialized theoretical knowledge, efficient computer programs, and high-performance computers for large-scale calculations. This paper presents recent results involving two real-world applications in concrete structures, where the aerodynamic parameters were estimated with the aid of computational fluid dynamics. Conventional quad-core computers were applied in simulations with the Finite Volume Method and a progressive methodology is presented, highlighting the main aspects of the simulation and allowing its generalization to other types of problems. The results confirm that the proposed methodology is promising in terms of computational cost, drag coefficient estimation and versatility of simulation parameters. These results also indicate that mid-performance computers can be applied for preliminary studies of aerodynamic parameters in design offices.

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Rometsch, Thomas. "Detecting vortices in fluid dynamics simulations using computer vision." Proceedings of the International Astronomical Union 16, S362 (June 2020): 398–403. http://dx.doi.org/10.1017/s1743921322001454.

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AbstractVortices are patches of fluid revolving around a central axis. They are ubiquitous in fluid dynamics. To the human eye, detecting vortices is a trivial task thanks to our inherent ability to identify patterns. To solve this task automatically, we developed the Vortector pipeline which was used to identify and characterize vortices in around one million snapshots of planet-disk interaction simulations in the context of planet formation. From the emergence of two regimes of vortex lifetime, one of which shows very long-lived vortices, we conclude that future resolved disk observations will predominantly detect vortices in the outer parts of protoplanetary disks.

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Dominguez, Hector, Orest Pizio, Laszlo Pusztai, and Stefan Sokolowski. "The Structural Properties and Diffusion of a Three-Dimensional Isotropic Core-Softened Model Fluid in Disordered Porous Media. Molecular Dynamics Simulation." Adsorption Science & Technology 25, no. 7 (September 2007): 479–91. http://dx.doi.org/10.1260/0263-6174.25.7.479.

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The microscopic structure and dynamic properties of an isotropic three-dimensional core-softened model fluid in disordered matrices of Lennard-Jones particles have been studied. Molecular dynamics computer simulations in Grand Canonical ensemble were used as the methodological tools. It was shown that the microscopic structure of the fluid is characterized by anomalies similar to those found in a bulk model, but that it is affected by the fluid-matrix interactions. The dynamic properties also exhibit anomalous dependence on fluid density, but the magnitude of these anomalies is suppressed in comparison to the bulk fluid model. The anomalous behaviour of the diffusion coefficient is attributed to structural changes in the first coordination shell of a given fluid particle. It seems that the anomalies can only be suppressed at matrix densities which are higher than those studied in the present work.

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Santos, D. A., I. Petri Junior, Marcos A. S. Barrozo, and Claudio Roberto Duarte. "Mixture of Particles' Influence in Computer Simulations of a Spouted Bed." Materials Science Forum 660-661 (October 2010): 448–53. http://dx.doi.org/10.4028/www.scientific.net/msf.660-661.448.

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This article aims to assess the influence of the way of simulating monoparticles as just monoparticles or as a mixture of particles, the latter, unlike the first, considering the effect of particle-particle interaction. The Eulerian–Eulerian multiphase model is used in the computational simulation of fluid dynamics of spouted beds and compared with experimental data. A half column of cylindrical spouted bed with a full plane glass attached to the front open surface of the bed as the transparent window was used for observation and photographing. Images of solid flows were recorded using a high speed camera (2000 frames per second). Glass beads with a diameter of 0.00368, 0.005 and 0.00252 mm are used as bed material. The simulated characteristic fluid dynamic curves of spouted bed for 0.15 m static bed heights (Ho) were obtained with good agreement with experimental data when the monoparticles was simulated as a mixture of particles with mixture’s percentage of 50%. The same occurred for the simulation of vertical velocities of particles profile, that is, when the monoparticles was simulated as a mixture of particles with mixture’s percentage of 50% we observed a more approach to the experimental data. It was also observed that the air concentration distribution seem to be independent of the changing of the composition.

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Colonna, Piero, and Paolo Silva. "Dense Gas Thermodynamic Properties of Single and Multicomponent Fluids for Fluid Dynamics Simulations." Journal of Fluids Engineering 125, no. 3 (May 1, 2003): 414–27. http://dx.doi.org/10.1115/1.1567306.

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The use of dense gases in many technological fields requires modern fluid dynamic solvers capable of treating the thermodynamic regions where the ideal gas approximation does not apply. Moreover, in some high molecular fluids, nonclassical fluid dynamic effects appearing in those regions could be exploited to obtain more efficient processes. This work presents the procedures for obtaining nonconventional thermodynamic properties needed by up to date computer flow solvers. Complex equations of state for pure fluids and mixtures are treated. Validation of sound speed estimates and calculations of the fundamental derivative of gas dynamics Γ are shown for several fluids and particularly for Siloxanes, a class of fluids that can be used as working media in high-temperature organic Rankine cycles. Some of these fluids have negative Γ regions if thermodynamic properties are calculated with the implemented modified Peng-Robinson thermodynamic model. Results of flow simulations of one-dimensional channel and two-dimensional turbine cascades will be presented in upcoming publications.

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Espinosa, Jorge R., Pablo Sampedro, Chantal Valeriani, Carlos Vega, and Eduardo Sanz. "Lattice mold technique for the calculation of crystal nucleation rates." Faraday Discussions 195 (2016): 569–82. http://dx.doi.org/10.1039/c6fd00141f.

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We present a new simulation method for the calculation of crystal nucleation rates by computer simulation. The method is based on the use of molds to induce crystallization in state points where nucleation is a rare event. The mold is a cluster of potential energy wells placed in the lattice positions of the solid. The method has two distinct steps. In the first one the probability per unit volume of forming a sub-critical crystal cluster in the fluid is computed by means of thermodynamic integration. The thermodynamic route consists in gradually switching on an attractive interaction between the wells and the fluid particles. In the second step, the frequency with which such cluster becomes post-critical is computed in Molecular Dynamics simulations with the mold switched on. We validate our method with a continuous version of the hard sphere potential and with the sodium chloride Tosi–Fumi model. In all studied state points we obtain a good agreement with literature data obtained from other rare event simulation techniques. Our method is quite suitable for the study of both crystal nucleation of arbitrarily complex structures and the competition between different polymorphs in the nucleation stage.

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Kovalev, I. S. "MATHEMATICAL AND COMPUTER SIMULATION OF THE COMMERTIAL VEHICLE’S HYDRAULIC RETARDER." Vestnik SibADI 15, no. 3 (July 11, 2018): 400–411. http://dx.doi.org/10.26518/2071-7296-2018-3-400-411.

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Introduction.The article represents the mathematical model of commercial vehicle’s hydraulic retarder. The model is based on the mathematical model of the variable filling hydraulic dynamometer.Materials and methods.The retarder model was designed with the possibility of its integration with the mathematical model of the engine cooling system. For this purpose, the state function of fluid temperature in a working chamber of the retarder was added to the retarder model. Consequently, fluid compression in the working chamber was included into the model to avoid unlimited filling because of possible high pressure at the retarder inlet.Results.The simulation model of the retarder was established as LMS Amesim submodel using C-programming language. For testing, the retarder simulation model was integrated with the Amesim models of the engine cooling system and with the powertrain and vehicle movement dynamics. In addition, brake torque regulation wassynthesized on PI controllers.Discussion and conclusions. During simulation of the vehicle movement on the mountain route expectable results were obtain, such as continuous braking via the retarder, which led to increasing of the cooling system’s fluid temperature. Therefore, overfilling of the retarder working chamber didn’t occur through the fluid compression. The retarder model could be applied to determine retarder design influence at vehicle functioning. For instance, it could be used for development of the algorithms’ control.

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Fan, Zhe, Yu-Chuan Kuo, Ye Zhao, Feng Qiu, Arie Kaufman, and William Arcieri. "Visual simulation of thermal fluid dynamics in a pressurized water reactor." Visual Computer 25, no. 11 (January 23, 2009): 985–96. http://dx.doi.org/10.1007/s00371-008-0309-x.

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Song, Yuan, and Insu Paek. "Prediction and Validation of the Annual Energy Production of a Wind Turbine Using WindSim and a Dynamic Wind Turbine Model." Energies 13, no. 24 (December 14, 2020): 6604. http://dx.doi.org/10.3390/en13246604.

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In this study, dynamic simulations of a wind turbine were performed to predict its dynamic performance, and the results were experimentally validated. The dynamic simulation received time-domain wind speed and direction data and predicted the power output by applying control algorithms. The target wind turbine for the simulation was a 2 MW wind turbine installed in an onshore wind farm. The wind speed and direction data for the simulation were obtained from WindSim, which is a commercial computational fluid dynamics (CFD) code for wind farm design, and measured wind speed and direction data with a mast were used for WindSim. For the simulation, the wind turbine controller was tuned to match the power curve of the target wind turbine. The dynamic simulation was performed for a period of one year, and the results were compared with the results from WindSim and the measurement. It was found from the comparison that the annual energy production (AEP) of a wind turbine can be accurately predicted using a dynamic wind turbine model with a controller that takes into account both power regulations and yaw actions with wind speed and direction data obtained from WindSim.

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Journal articles on the topic 'Fluid dynamics – Computer simulation'

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