Relevant bibliographies by topics / Turbulent fluxe

Academic literature on the topic 'Turbulent fluxe'

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Published: 14 March 2023

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Journal articles on the topic "Turbulent fluxe"

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Modliński, Norbert J., Włodzimierz K. Kordylewski, and Maciej P. Jakubiak. "Numerical Simulation of O3 and NO Reacting in a Tubular Flow Reactor." Chemical and Process Engineering 34, no. 3 (September 1, 2013): 361–73. http://dx.doi.org/10.2478/cpe-2013-0029.

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Abstract A process capable of NOx control by ozone injection gained wide attention as a possible alternative to proven post combustion technologies such as selective catalytic (and non-catalytic) reduction. The purpose of the work was to develop a numerical model of NO oxidation with O3 that would be capable of providing guidelines for process optimisation during different design stages. A Computational Fluid Dynamics code was used to simulate turbulent reacting flow. In order to reduce computation expense a 11-step global NO - O3 reaction mechanism was implemented into the code. Model performance was verified by the experiment in a tubular flow reactor for two injection nozzle configurations and for two O3/NO ratios of molar fluxe. The objective of this work was to estimate the applicability of a simplified homogeneous reaction mechanism in reactive turbulent flow simulation. Quantitative conformity was not completely satisfying for all examined cases, but the final effect of NO oxidation was predicted correctly at the reactor outlet.
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Durden, D. J., C. J. Nappo, M. Y. Leclerc, H. F. Duarte, G. Zhang, M. J. Parker, and R. J. Kurzeja. "On the impact of wave-like disturbances on turbulent fluxes and turbulence statistics in nighttime conditions: a case study." Biogeosciences 10, no. 12 (December 23, 2013): 8433–43. http://dx.doi.org/10.5194/bg-10-8433-2013.

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Abstract. The interpretation of flux measurements in nocturnal conditions is typically fraught with challenges. This paper reports on how the presence of wave-like disturbances in a time series, can lead to an overestimation of turbulence statistics, errors when calculating the stability parameter, erroneous estimation of the friction velocity u* used to screen flux data, and errors in turbulent flux calculations. Using time series of the pressure signal from a microbarograph, wave-like disturbances at an AmeriFlux site are identified. The wave-like disturbances are removed during the calculation of turbulence statistics and turbulent fluxes. Our findings suggest that filtering eddy-covariance data in the presence of wave-like events prevents both an~overestimation of turbulence statistics and errors in turbulent flux calculations. Results show that large-amplitude wave-like events, events surpassing three standard deviations, occurred on 18% of the nights considered in the present study. Remarkably, on flux towers located in a very stably stratified boundary-layer regime, the presence of a gravity wave can enhance turbulence statistics more than 50%. In addition, the presence of the disturbance modulates the calculated turbulent fluxes of CO2 resulting in erroneous turbulent flux calculations of the order of 10% depending on averaging time and pressure perturbation threshold criteria. Furthermore, the friction velocity u* was affected by the presence of the wave, and in at least one case, a 10% increase caused u* to exceed the arbitrary 0.25 m s−1 threshold used in many studies. This results in an unintended bias in the data selected for analysis in the flux calculations. The impact of different averaging periods was also examined and found to be variable specific. These early case study results provide an insight into errors introduced when calculating "purely" turbulent fluxes. These results could contribute to improving modeling efforts by providing more accurate inputs of both turbulent kinetic energy, and isolating the turbulent component of u* for flux selection in the stable nocturnal boundary layer.
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Maroneze, Rafael, Otávio Costa Acevedo, and Felipe Denardin Costa. "RELAÇÃO ENTRE VELOCIDADE DO VENTO E ENERGIA CINÉTICA TURBULENTA EM MODELOS SIMPLIFICADOS DA CAMADA LIMITE NOTURNA." Ciência e Natura 38 (July 20, 2016): 75. http://dx.doi.org/10.5902/2179460x20091.

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The determination of the turbulent fluxes in very stable conditions is done, generally, through parameterizations. In this work the turbulent fluxes are estimated, by using a simplified model, through prognostic equations for the turbulent intensity, the sensible heat flux and the temperature variance. The results indicate that the model is able to reproduce both atmospheric coupling and the intermittent character of the turbulence in very stable conditions.
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Liu, Lei, Yu Shi, and Fei Hu. "Characteristics of intrinsic non-stationarity and its effect on eddy-covariance measurements of CO<sub>2</sub> fluxes." Nonlinear Processes in Geophysics 29, no. 1 (March 24, 2022): 123–31. http://dx.doi.org/10.5194/npg-29-123-2022.

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Abstract. Stationarity is a critical assumption in the eddy-covariance method that is widely used to calculate turbulent fluxes. Many methods have been proposed to diagnose non-stationarity attributed to external non-turbulent flows. In this paper, we focus on intrinsic non-stationarity (IN) attributed to turbulence randomness. The detrended fluctuation analysis is used to quantify IN of CO2 turbulent fluxes in the downtown of Beijing. Results show that the IN is common in CO2 turbulent fluxes and is a small-scale phenomenon related to the inertial sub-range turbulence. The small-scale IN of CO2 turbulent fluxes can be simulated by the Ornstein–Uhlenbeck (OU) process as a first approximation. Based on the simulation results, we find that the flux-averaging time should be greater than 27 s to avoid the effects of IN. Besides, the non-stationarity diagnosis methods that do not take into account IN would possibly make a wrong diagnosis with some parameters.
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Durden, D. J., C. J. Nappo, M. Y. Leclerc, H. F. Duarte, G. Zhang, L. B. M. Pires, M. J. Parker, and R. J. Kurzeja. "On the impact of atmospheric waves on fluxes and turbulence statistics during nighttime conditions: a case study." Biogeosciences Discussions 10, no. 3 (March 14, 2013): 5149–73. http://dx.doi.org/10.5194/bgd-10-5149-2013.

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Abstract. The interpretation of flux measurements in the nocturnal stable boundary layer is typically fraught with difficulties. This paper reports on how the presence of waves in a time series leads to an overestimation of turbulence statistics and errors in turbulent flux calculations. Using time series of the pressure signal from a microbarograph, the presence of waves at a flux measurement site near Aiken, SC is identified and removed. Our findings suggest that filtering of eddy-covariance data in the presence of wave events prevents both an overestimation of turbulence statistics and errors in turbulent flux calculations. The results showed that large amplitude wave-like events occurred on 31% of the nights considered in the present study. Remarkably, in low-turbulence environments, the presence of a gravity wave can enhance turbulence statistics more than 50%. The presence of the wave modulates the calculated turbulent fluxes of CO2, resulting in erroneous flux calculations of the order of 10% depending on the averaging time and pressure perturbation threshold criteria. In addition, u∗ was affected by the presence of the wave, and in at least one case, a 10% increase caused u∗ to exceed the arbitrary 0.25 ms–1 threshold used in many studies. These preliminary results suggest that biases due to nocturnal atmospheric phenomena can easily creep unnoticed into flux data. The impact of different averaging periods was found to depend on the choice of the variables. This is a product of the width of the averaging window in relation to the wave cycle and dealt with the phase relationship of the variables being analyzed; hence, these errors are primarily introduced through our processing methods. These results provide a novel insight into errors introduced in turbulent fluxes. By contributing more accurate inputs of both turbulent kinetic energy and u∗, these results could be invaluable in improving modeling efforts applied to nocturnal exchange.
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Huang, Junji, Jorge-Valentino Bretzke, and Lian Duan. "Assessment of Turbulence Models in a Hypersonic Cold-Wall Turbulent Boundary Layer." Fluids 4, no. 1 (February 26, 2019): 37. http://dx.doi.org/10.3390/fluids4010037.

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In this study, the ability of standard one- or two-equation turbulence models to predict mean and turbulence profiles, the Reynolds stress, and the turbulent heat flux in hypersonic cold-wall boundary-layer applications is investigated. The turbulence models under investigation include the one-equation model of Spalart–Allmaras, the baseline k - ω model by Menter, as well as the shear-stress transport k - ω model by Menter. Reynolds-Averaged Navier-Stokes (RANS) simulations with the different turbulence models are conducted for a flat-plate, zero-pressure-gradient turbulent boundary layer with a nominal free-stream Mach number of 8 and wall-to-recovery temperature ratio of 0.48 , and the RANS results are compared with those of direct numerical simulations (DNS) under similar conditions. The study shows that the selected eddy-viscosity turbulence models, in combination with a constant Prandtl number model for turbulent heat flux, give good predictions of the skin friction, wall heat flux, and boundary-layer mean profiles. The Boussinesq assumption leads to essentially correct predictions of the Reynolds shear stress, but gives wrong predictions of the Reynolds normal stresses. The constant Prandtl number model gives an adequate prediction of the normal turbulent heat flux, while it fails to predict transverse turbulent heat fluxes. The discrepancy in model predictions among the three eddy-viscosity models under investigation is small.
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Banerjee, Tirtha, Frederik De Roo, and Matthias Mauder. "Connecting the Failure of K Theory inside and above Vegetation Canopies and Ejection–Sweep Cycles by a Large-Eddy Simulation." Journal of Applied Meteorology and Climatology 56, no. 12 (December 2017): 3119–31. http://dx.doi.org/10.1175/jamc-d-16-0363.1.

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AbstractParameterizations of biosphere–atmosphere interaction processes in climate models and other hydrological applications require characterization of turbulent transport of momentum and scalars between vegetation canopies and the atmosphere, which is often modeled using a turbulent analogy to molecular diffusion processes. Simple flux–gradient approaches (K theory) fail for canopy turbulence, however. One cause is turbulent transport by large coherent eddies at the canopy scale, which can be linked to sweep–ejection events and bear signatures of nonlocal organized eddy motions. The K theory, which parameterizes the turbulent flux or stress proportional to the local concentration or velocity gradient, fails to account for these nonlocal organized motions. The connection to sweep–ejection cycles and the local turbulent flux can be traced back to the turbulence triple moment . In this work, large-eddy simulation is used to investigate the diagnostic connection between the failure of K theory and sweep–ejection motions. Analyzed schemes are quadrant analysis and complete and incomplete cumulant expansion methods. The latter approaches introduce a turbulence time scale in the modeling. Furthermore, it is found that the momentum flux and sensible heat flux need different formulations for the turbulence time scale. Accounting for buoyancy in stratified conditions is also deemed important in addition to accounting for nonlocal events to predict the correct momentum or scalar fluxes.
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Kawata, Takuya, and Takahiro Tsukahara. "Spectral Analysis on Transport Budgets of Turbulent Heat Fluxes in Plane Couette Turbulence." Energies 15, no. 14 (July 20, 2022): 5258. http://dx.doi.org/10.3390/en15145258.

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In recent years, scale-by-scale energy transport in wall turbulence has been intensively studied, and the complex spatial and interscale transfer of turbulent energy has been investigated. As the enhancement of heat transfer is one of the most important aspects of turbulence from an engineering perspective, it is also important to study how turbulent heat fluxes are transported in space and in scale by nonlinear multi-scale interactions in wall turbulence as well as turbulent energy. In the present study, the spectral transport budgets of turbulent heat fluxes are investigated based on direct numerical simulation data of a turbulent plane Couette flow with a passive scalar heat transfer. The transport budgets of spanwise spectra of temperature fluctuation and velocity-temperature correlations are investigated in detail in comparison to those of the corresponding Reynolds stress spectra. The similarity and difference between those scale-by-scale transports are discussed, with a particular focus on the roles of interscale transport and spatial turbulent diffusion. As a result, it is found that the spectral transport of the temperature-related statistics is quite similar to those of the Reynolds stresses, and in particular, the inverse interscale transfer is commonly observed throughout the channel in both transport of the Reynolds shear stress and wall-normal turbulent heat flux.
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MASSERONI, DANIELE, CHIARA CORBARI, and MARCO MANCINI. "Limitations and improvements of the energy balance closure with reference to experimental data measured over a maize field." Atmósfera 27, no. 4 (January 13, 2015): 335–52. http://dx.doi.org/10.20937/atm.2014.27.04.01.

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The use of energy fluxes data to validate land surface models requires that energy balance closure conservationis satisfied, but usually this condition is not verified when the available energy is bigger than the sumof turbulent vertical fluxes. In this work, a comprehensive evaluation of energy balance closure problems isperformed on a 2012 data set from Livraga obtained by a micrometeorological eddy covariance station locatedin a maize field in the Po Valley. Energy balance closure is calculated by statistical regression of turbulentenergy fluxes and soil heat flux against available energy. Generally, the results indicate a lack of closure witha mean imbalance in the order of 20%. Storage terms are the main reason for the unclosed energy balance butalso the turbulent mixing conditions play a fundamental role in reliable turbulent flux estimations. Recentlyintroduced in literature, the energy balance problem has been studied as a scale problem. A representativesource area for each flux of the energy balance has been analyzed and the closure has been performed infunction of turbulent flux footprint areas. Surface heterogeneity and seasonality effects have been studied to understand the influence of canopy growth on the energy balance closure. High frequency data have beenused to calculate co-spectral and ogive functions, which suggest that an averaging period of 30 min may misstemporal scales that contribute to the turbulent fluxes. Finally, latent and sensible heat random error estimationsare computed to give information about the measurement system and turbulence transport deficiencies
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Younis, Bassam A., Charles G. Speziale, and Timothy T. Clark. "A rational model for the turbulent scalar fluxes." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 461, no. 2054 (February 8, 2005): 575–94. http://dx.doi.org/10.1098/rspa.2004.1380.

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The paper reports on an alternative approach to modelling the turbulent scalar fluxes that arise from time averaging the transport equation for a scalar. In this approach, a functional relationship between these fluxes and various tensor quantities is constructed with guidance from the exact equations governing the transport of fluxes. Results from tensor representation theory are then used to obtain an explicit relationship between the fluxes and the terms in the assumed functional relationship. Where turbulence length– and time–scales are implied, these are determined from two scalar quantities: the turbulence kinetic energy and its rate of dissipation by viscous action. The general representation is then reduced by certain justifiable assumptions to yield a practical model for the turbulent scalar fluxes that is explicit and algebraic in these quantities and one that correctly reflects their dependence on the gradients of mean velocity and on the details of the turbulence. Examination of alternative algebraic models shows most to be subsets of the present proposal. The new model is calibrated using results from large–eddy simulations (LESs) of homogeneous turbulence with passive scalars and then assessed by reference to benchmark data from heated turbulent shear flows. The results obtained show the model to correctly predict the anisotropy of the turbulent diffusivity tensor. The asymmetric nature of this tensor is also recovered, but only qualitatively, there being significant quantitative differences between the model predictions and the LES results. Finally, comparisons with data from benchmark two–dimensional free shear flows show the new model to yield distinct improvements over other algebraic scalar–flux closures.
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Dissertations / Theses on the topic "Turbulent fluxe"

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Gerbi, Gregory Peter. "Observations of turbulent fluxes and turbulence dynamics in the ocean surface boundary layer." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45778.

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Thesis (Ph. D.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2008.
Includes bibliographical references (p. 110-119).
This study presents observations of turbulence dynamics made during the low winds portion of the Coupled Boundary Layers and Air-Sea Transfer experiment (CBLAST-Low). Observations were made of turbulent fluxes, turbulent kinetic energy, and the length scales of flux-carrying and energy-containing eddies in the ocean surface boundary layer. A new technique was developed to separate wave and turbulent motions spectrally, using ideas for turbulence spectra that were developed in the study of the bottom boundary layer of the atmosphere. The observations of turbulent fluxes allowed the closing of heat and momentum budgets across the air-sea interface. The observations also show that flux-carrying eddies are similar in size to those expected in rigid-boundary turbulence, but that energy-containing eddies are smaller than those in rigid-boundary turbulence. This suggests that the relationship between turbulent kinetic energy, depth, and turbulent diffusivity are different in the ocean surface boundary layer than in rigid-boundary turbulence. The observations confirm previous speculation that surface wave breaking provides a surface source of turbulent kinetic energy that is transported to depth where it dissipates. A model that includes the effects of shear production, wave breaking and dissipation is able to reproduce the enhancement of turbulent kinetic energy near the wavy ocean surface. However, because of the different length scale relations in the ocean surface boundary layer, the empirical constants in the energy model are different from the values that are used to model rigid-boundary turbulence. The ocean surface boundary layer is observed to have small but finite temperature gradients that are related to the boundary fluxes of heat and momentum, as assumed by closure models. However, the turbulent diffusivity of heat in the surface boundary layer is larger than predicted by rigid-boundary closure models. Including the combined effects of wave breaking, stress, and buoyancy forcing allows a closure model to predict the turbulent diffusivity for heat in the ocean surface boundary layer.
by Gregory Peter Gerbi.
Ph.D.
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Dupland, Laure. "Modélisation de la turbulence thermique : modèles algébriques pour la prévision des flux de chaleur turbulents." Toulouse, ENSAE, 2005. http://www.theses.fr/2005ESAE0023.

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Cette thèse traite des modèles thermiques algébriques explicites EAHFM pour la prévision des flux de chaleur turbulents. Moyennant une condition d’équilibre local de la turbulence, l’équation de transport de ces derniers se simplifie en une relation algébrique, s'affranchissant de l'hypothèse de nombre de Prandtl turbulent constant. Le flux de chaleur résultant est alors désaligné du gradient de température moyenne, palliant ainsi les défauts des modèles à diffusivité turbulente. L'expression du flux de chaleur turbulent dépendant des quatre échelles de la turbulence dynamique et thermique (k, ε, k[indice ϑ] et ε[indice ϑ]), la résolution de leur équation de transport est requise. Toutefois, en supposant constant le rapport r des temps caractéristiques de la turbulence, on s’exempte de la résolution des deux équations de transport thermiques. Des contraintes sur les constantes du modèle ont été développées de manière à satisfaire certains comportements physiques de base : écoulements homogènes et couche limite soumise ou non à un gradient de pression adverse. Un jeu de constantes a pu être obtenu dans chacune des deux approches (hypothèse sur r constant ou non). Un modèle de paroi a été développé de sorte que les composantes du flux de chaleur s’amortissent correctement au voisinage d’une paroi. Le modèle ainsi obtenu a été dans un premier temps appliqué aux écoulements de similitude, puis sa version simplifiée en association avec le modèle à deux équations k-kL en formulation EARSM a été implantée dans le code Navier-Stokes elsA de l'ONERA pour être validée sur les écoulements de plaque plane chauffée, de jet débouchant et de jet impactant une paroi chauffée.
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Brol, Keila Belquiz. "Modelagem e análise de selos de fluxo aplicados a máquinas rotativas." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263055.

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Orientador: Katia Lucchesi Cavalca
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
Made available in DSpace on 2018-08-17T18:45:51Z (GMT). No. of bitstreams: 1 Brol_KeilaBelquiz_M.pdf: 7087689 bytes, checksum: b81e96d33b1146da143fae0859da2363 (MD5) Previous issue date: 2011
Resumo: O desenvolvimento de modelos matemáticos que visam simular as características operacionais das máquinas rotativas é importante para representar uma variedade de fenômenos expressivos que se manifestam durante a operação, para tanto é necessário a modelagem dos componentes que caracterizam o comportamento dinâmico do sistema. Este trabalho tem por objetivo determinar os parâmetros físicos que integram os selos de fluxo de folga fixa e angular ao modelo global de sistemas rotativos. As rigidezes e os amortecimentos são obtidos através da solução de equações governantes para líquidos escoando em selos anulares pelo método clássico das perturbações de ordem máxima um e a solução da ordem zero permite demonstrar a variação da pressão e velocidade para as equações de ordem zero. Os resultados obtidos foram validados com os valores apresentados pela literatura. O resultado deste trabalho poderá ser aplicado na modelagem global de uma máquina rotativa, de modo a tornar a análise mais completa do conjunto girante
Abstract: The development of mathematical models designed to simulate operational characteristics is important to represent a wide variety of expressive phenomena that manifest during the operation, and therefore it is necessary the components modeling that characterize the system dynamic behavior. This study aims to determine the physical parameters that influence the flow seals to fixed angles and variables in the global rotating systems model. The stiffness and damping are obtained by solving the governing equations for fluid flowing in the annular seals using the classic perturbation method of maximal order one. The zero-order solution allows to demonstrate the pressure and speed variation to zero order. The results were validated with the similar tests reported in the literature. This work results are eligible to be applied to model a global rotating machine in order to make a more complete rotor analysis
Mestrado
Mecanica dos Sólidos e Projeto Mecanico
Mestre em Engenharia Mecânica
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Salewski, Matthew. "Flux and dissipation of energy in the LET theory of turbulence." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4684.

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The first part of this thesis examines and compares the separate closure formalisms of Wyld and Martin, Siggia, and Rose (MSR). The simplicity of Wyld’s perturbation scheme is offset by an incorrect renormalisation, this contrasts with the formally exact analysis of MSR. The work here shows that a slight change in Wyld’s renormalisation keeps the main results intact and, in doing so, demonstrates that this formalism is equivalent to MSR. The remainder of the thesis is concerned with turbulent dissipation. A numerical solution of the Local Energy Transfer theory, or LET, is reworked and extended to compute decaying and forced turbulence at large Reynolds numbers. Using this numerical simulation, the phenomenon of turbulent dissipation is investigated. In order to use decaying turbulence to study the turbulent dissipation rate as a function of Reynolds number, it is necessary to choose an appropriate time with which a measurement can be taken. Using phenomenological arguments of the evolution of a turbulent fluid, criteria for establishing such a time are developed. An important study in turbulence is the dissipation rate in the limit of vanishing viscosity, also known as the dissipation anomaly. This thesis derives an equation for the dissipation rate from the spectral energy balance equation. Using the LET computation for both decaying and forced turbulence, results are obtained that can be used along with the equation to study the mechanisms behind the dissipation anomaly. It is found that there is a difference in the behaviour of the normalised dissipation rate between decaying and forced turbulence and, for both cases, it is largely controlled by the energy flux.
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Weng, Wensong. "Turbulent air flow and fluxes over low hills." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333317.

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Kaye, Nigel Gregory. "Interaction of turbulent plumes." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323741.

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Thompson, Andrew F. "Eddy fluxes in baroclinic turbulence." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2006. http://wwwlib.umi.com/cr/ucsd/fullcit?p3225998.

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Thesis (Ph. D.)--University of California, San Diego, 2006.
Title from first page of PDF file (viewed October 10, 2006). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 173-182).
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Mickett, John B. "Turbulent entrainment fluxes within the eastern Pacific warm pool /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/11005.

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Bernard, Donald Edward. "Optimization of Turbulent Prandtl Number in Turbulent, Wall Bounded Flows." ScholarWorks @ UVM, 2018. https://scholarworks.uvm.edu/graddis/824.

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After nearly 50 years of development, Computational Fluid Dynamics (CFD) has become an indispensable component of research, forecasting, design, prototyping and testing for a very broad spectrum of fields including geophysics, and most engineering fields (mechanical, aerospace, biomedical, chemical and civil engineering). The fastest and most affordable CFD approach, called Reynolds-Average-Navier-Stokes (RANS) can predict the drag around a car in just a few minutes of simulation. This feat is possible thanks to simplifying assumptions, semi-empirical models and empirical models that render the flow governing equations solvable at low computational costs. The fidelity of RANS model is good to excellent for the prediction of flow rate in pipes or ducts, drag, and lift of solid objects in Newtonian flows (e.g. air, water). RANS solutions for the prediction of scalar (e.g. temperature, pollutants, combustable chemical species) transport do not generally achieve the same level of fidelity. The main culprit is an assumption, called Reynolds analogy, which assumes analogy between the transport of momentum and scalar. This assumption is found to be somewhat valid in simple flows but fails for flows in complex geometries and/or in complex fluids. This research explores optimization methods to improve upon existing RANS models for scalar transport. Using high fidelity direct numerical simulations (numerical solutions in time and space of the exact transport equations), the most common RANS model is a-priori tested and investigated for the transport of temperature (as a passive scalar) in a turbulent channel flow. This one constant model is then modified to improve the prediction of the temperature distribution profile and the wall heat flux. The resulting modifications provide insights in the model’s missing physics and opens new areas of investigation for the improvement of the modeling of turbulent scalar transport.
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Cambra, Rémi. "Etude des flux turbulents à l'interface air-mer à partir de données de la plateforme OCARINA." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLV024/document.

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Les échanges de chaleur et de quantité de mouvement à l'interface-océan atmosphère jouent un rôle majeur dans la formation et la dynamique des masses d'air et d'eau. Malgré des décennies de recherche, nous avons encore besoin d'améliorer nos connaissances sur ces échanges, et plus spécifiquement nos connaissances sur les flux turbulents, qui sont des variables clés dans les modèles météorologiques et de climat. Dans ces modèles, les processus turbulents sont des processus sous-maille, non-résolus explicitement, ainsi les flux turbulents doivent être modélisés, au travers de paramétrisations, qui sont pour la plupart réalisées à partir de la théorie des similitudes de Monin-Obukhov [1954]. Cependant, d'une part, l'utilisation d'un modèle implique que les coefficients doivent être ajustés. D'autre part, le modèle lui-même peut demander des améliorations. Malheureusement, l'obtention d'estimations de flux avec une bonne précision est un gros défi, à cause des effets intrusifs de la plate-forme sur la mesure, de la précision limité des instruments et des capacités d'échantillonnages propres de chaque instrument.Notre étude porte sur l'estimation des flux turbulents en mer à partir de mesures réalisées avec la nouvelle plate-forme OCARINA (trimaran autonome) lors des campagnes STRASSE 2012 et AMOP 2014. Nous analysons les caractéristiques de la turbulence dans la couche limite de surface, nous estimons les flux turbulents par différentes méthodes, et nous comparons les valeurs des flux en fonction des conditions environnementales, en prenant en compte l'état de mer
Exchanges of heat and momentum at the air-sea interface play a major role in the formation and the dynamics of water and air masses. In spite of decades of research, we still need to improve our knowledge of these exchanges, and more specifically our knowledge of turbulent fluxes, which are key variables in meteorological and climate models. In these models, sub-grid turbulent processes, thus turbulent fluxes also have to be modeled, which is mostly done with the Monin-Obukhov (1954, MOS hereafter) similarity theory. However, on the one hand, the use of a model implies that coefficients have to be adjusted. On the other hand, the model itself may require improvements. Unfortunately, obtaining flux estimates that have a good accuracy is a challenging effort, because of the intrusive effect of the platform, the limited accuracy the instruments, and because the instruments have their own sampling volume.Our study focuses on the estimation of turbulent fluxes at sea from measurements made with the new OCARINA platform (autonomous trimaran) during two campaigns : STRASSE 2012 and AMOP 2014. We analyze the characteristics of turbulence in the surface boundary layer, we estimate the turbulent fluxes by different methods, and compare the values of fluxes depending on environmental conditions, taking into account the sea state
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Books on the topic "Turbulent fluxe"

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Center, Ames Research, ed. Large eddy interactions in a turbulent channel flow. Moffett Field, Calif: National Aeronautics and Space Administration, Ames Research Center, 1985.

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Smith, S. A. Turbulent fluxes in cumulus cloud capped boundary layers. Manchester: UMIST, 1993.

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J, Dobosy Ronald, Birdwell Kevin R, and Air Resources Laboratory (U.S.), eds. Airborne measurements of mass, momentum, and energy fluxes for the Boardman-Arm Regional Flux Experiment--1991 preliminary data release. Silver Spring, Md: U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, Environmental Research Laboratories, Air Resources Laboratory, 1993.

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Morrison, J. H. Flux-difference split scheme for turbulent transport equations. New York, N. Y: American Institute of Aeronautics and Astronautics, 1990.

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Center, Langley Research, ed. A representation for the turbulent mass flux contribution to Reynolds-stress and two-equation closures for compressible turbulence. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1993.

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Center, Langley Research, ed. A representation for the turbulent mass flux contribution to Reynolds-stress and two-equation closures for compressible turbulence. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1993.

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Institute for Computer Applications in Science and Engineering., ed. Toward a turbulence constitutive relation for rotating flows. Hampton, Va: Institute for Computer Applications in Science and Engineering, NASA Langley Research Center, 1996.

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Zaman, K. B. M. O., Reshotko Eli, and United States. National Aeronautics and Space Administration., eds. Turbulent heat flux measurements in a transitional boundary layer. [Washington, DC]: National Aeronautics and Space Administration, 1992.

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Zaman, K. B. M. Q., Reshotko E, and United States. National Aeronautics and Space Administration., eds. Turbulent heat flux measurements in a transitional boundary layer. [Washington, DC]: National Aeronautics and Space Administration, 1992.

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W, Lindsay R., and United States. National Aeronautics and Space Administration., eds. Surface turbulent fluxes over pack ice inferred from TOVS observations. [Washington, DC: National Aeronautics and Space Administration, 1996.

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Book chapters on the topic "Turbulent fluxe"

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Kaller, Thomas, Alexander Doehring, Stefan Hickel, Steffen J. Schmidt, and Nikolaus A. Adams. "Assessment of RANS Turbulence Models for Straight Cooling Ducts: Secondary Flow and Strong Property Variation Effects." In Notes on Numerical Fluid Mechanics and Multidisciplinary Design, 309–21. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-53847-7_20.

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Abstract We present well-resolved RANS simulations of two generic asymmetrically heated cooling channel configurations, a high aspect ratio cooling duct operated with liquid water at $$Re_b = 110 \times 10^3$$ and a cryogenic transcritical channel operated with methane at $$Re_b = 16 \times 10^3$$. The former setup serves to investigate the interaction of turbulence-induced secondary flow and heat transfer, and the latter to investigate the influence of strong non-linear thermodynamic property variations in the vicinity of the critical point on the flow field and heat transfer. To assess the accuracy of the RANS simulations for both setups, well-resolved implicit LES simulations using the adaptive local deconvolution method as subgrid-scale turbulence model serve as comparison databases. The investigation focuses on the prediction capabilities of RANS turbulence models for the flow as well as the temperature field and turbulent heat transfer with a special focus on the turbulent heat flux closure influence.
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Moncrieff, John. "Surface Turbulent Fluxes." In Vegetation, Water, Humans and the Climate, 173–82. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-642-18948-7_15.

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Borghi, Roland, and Fabien Anselmet. "Modeling Turbulent Dispersion Fluxes." In Turbulent Multiphase Flows with Heat and Mass Transfer, 119–64. Hoboken, USA: John Wiley & Sons, Inc., 2014. http://dx.doi.org/10.1002/9781118790052.ch6.

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Verver, Gé. "On Chemistry Affecting the Turbulent Flux and Turbulence Affecting Chemistry." In Air Pollution Modeling and Its Application XIII, 347–55. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/978-1-4615-4153-0_35.

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Lysak, Robert L., and Yan Song. "Formation of flux ropes by turbulent reconnection." In Physics of Magnetic Flux Ropes, 525–32. Washington, D. C.: American Geophysical Union, 1990. http://dx.doi.org/10.1029/gm058p0525.

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Chiu, Long S., Si Gao, and Chung-Lin Shie. "Satellite-Based Ocean Surface Turbulent Fluxes." In Satellite-based Applications on Climate Change, 165–81. Dordrecht: Springer Netherlands, 2013. http://dx.doi.org/10.1007/978-94-007-5872-8_11.

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Prueger, John H., and William P. Kustas. "Aerodynamic Methods for Estimating Turbulent Fluxes." In Agronomy Monographs, 407–36. Madison, WI, USA: American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, 2015. http://dx.doi.org/10.2134/agronmonogr47.c18.

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Anxo, Dominique, and Harald Niklasson. "The Swedish Model: Revival after the Turbulent 1990s?" In European Employment Models in Flux, 81–104. London: Palgrave Macmillan UK, 2009. http://dx.doi.org/10.1057/9780230237001_3.

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Shaw, W. J. "Theory and Scaling of Lower Atmospheric Turbulence." In Surface Waves and Fluxes, 63–90. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-2069-9_4.

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Liu, W. T. "Remote Sensing of Surface Turbulence Heat Flux." In Surface Waves and Fluxes, 293–309. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-0627-3_7.

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Conference papers on the topic "Turbulent fluxe"

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Li, Genong, and Michael F. Modest. "Importance of Turbulence-Radiation Interactions in Turbulent Reacting Flows." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-33916.

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Traditional modeling of radiative transfer in reacting flows has ignored turbulence-radiation interactions (TRI). Radiative fluxes, flux divergences and radiative properties have been based on mean temperature and concentration fields. However, both experimental and theoretical work have suggested that mean radiative quantities may differ significantly from those predictions based on the mean parameters because of their strongly nonlinear dependence on the temperature and concentration fields. The composition PDF method is able to consider many nonlinear interactions rigorously, and the method is used here to study turbulence-radiation interactions. This paper tries to answer two basic questions: (1) whether turbulence-radiation interactions are important in turbulent flames or not; (2) if they are important, then what correlations need to be considered in the simulation to capture them. After conducting many flame simulations, it was observed that, on average, TRI effects account for about 1/3 of the total drop in flame peak temperature caused by radiative heat losses. In addition, this study shows that consideration of the temperature self correlation alone is not sufficient to capture TRI, but that the complete absorption coefficient–Planck function correlation must be considered.
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Quadros, Russell, Krishnendu Sinha, and Johan Larsson. "MODELLING OF TURBULENT ENERGY FLUX IN CANONICAL SHOCK-TURBULENCE INTERACTION." In Ninth International Symposium on Turbulence and Shear Flow Phenomena. Connecticut: Begellhouse, 2015. http://dx.doi.org/10.1615/tsfp9.960.

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Brakmann, Robin G., Robin Schöffler, Frank Kocian, Michael Schroll, Christian Willert, Martin Müller, and Edmund Kügeler. "Quantitative Flow Imaging of Film Cooling Jets in a Cross-Flow Using Particle Image Velocimetry and Computational Fluid Dynamics." In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-16141.

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Abstract The investigated generic configuration consists of cylindrical film cooling holes with a diameter of D = 8.4 mm and an inclination angle of α = 35°. The jets are characterized by a momentum flux ratio of I = 0.63, a density ratio of DR = 0.94 and a cross-flow Reynolds number of Re = 5500. Stereoscopic PIV allows creating a (pseudo) three dimensional image of the flow field. High resolution PIV is used to evaluate velocity fluctuations. The numerical model uses the SST and an EARSM turbulence model. The turbulent scalar fluxes are computed by a constant turbulent Prandtl number as well as algebraic models for the turbulent heat flux. The presented results consist of field cuts and line profiles of the velocity, vorticity and turbulent kinetic energy. All considered numerical options can predict the velocity field accurately, the SST turbulence model is the numerically most stable model and has the lowest demands in computational costs.
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Zedel, Len, and Alex Hay. "Coherent Doppler Sonar: Sediment Flux and Turbulent Velocities in a Wave Flume." In 26th International Conference on Coastal Engineering. Reston, VA: American Society of Civil Engineers, 1999. http://dx.doi.org/10.1061/9780784404119.197.

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Siddiqui, M. Salman, Adil Rasheed, Mandar Tabib, Eivind Fonn, and Trond Kvamsdal. "On Interactions Between Wind Turbines and the Marine Boundary Layer." In ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/omae2017-61688.

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Most mesoscale models are developed with grid resolution in the range of kilometers. Therefore, they may require spatial averaging to analyze flow behavior over the domain of interest. In doing so, certain important features of sub-grid scales are lost. Moreover, spatial averaging on the governing equations results in additional terms known as dispersive fluxes. These fluxes are ignored in the analysis. The aim of this paper is to identify the significance of these fluxes for accurate assessment of flow fields related to wind farm applications. The research objectives are hence twofold: 1) to quantify the impact of wind turbines on MBL characteristics. 2) to account for the magnitude of dispersive fluxes arising from spatial averaging and make a comparison against the turbulent flux values. To conduct the numerical study the NREL 5MW reference wind turbine model is employed with a RANS approach using k-ε turbulence model. The results are presented concerning spatially averaged velocity, wake deficit behind the turbine, dispersive and turbulent fluxes.
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Breidenthal, R. E. "Wall Heat Flux Under Persistent Vortices." In ASME 2002 Joint U.S.-European Fluids Engineering Division Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/fedsm2002-31244.

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It is commonly perceived that turbulent flows yield turbulent wall fluxes, while laminar flows yield correspondingly laminar wall fluxes. Experiments support a recent theory that turbulent flows can yield laminar wall fluxes if the flow is “persistent.” Adding strong, stationary vortices to a turbulent boundary layer lowers the wall heat flux to a laminar value.
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Straußwald, Michael, Karin Schmid, Hagen Müller, and Michael Pfitzner. "Experimental and Numerical Investigation of Turbulent Mixing in Film Cooling Applications." In ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-64650.

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Fundamental knowledge on the flow dynamics and in particular the turbulent heat flux in film cooling flows is essential for the future design process of efficient cooling geometries. Thermographic PIV has been used to measure temperature and velocity fields in flows emanating from cylindrical effusion holes simultaneously. The measurements were carried out in a closed-loop, heated wind tunnel facility at a repetition rate of 6 kHz. Due to the high frame rate of the measurements, the unsteady flow dynamics could be resolved. For a density ratio of DR = 1.6 and a momentum ratio of I = 8, the jet ejected from the cylindrical effusion hole lifts off the surface. From the instantaneous measurements it could be observed that pockets of hot air are entrained into the coolant forcing the relatively fast cooling air to dodge the slow main flow air. These shear layer fluctuations result in turbulent heat fluxes that do not follow the gradient diffusion hypothesis which is often used in RANS models. In addition to these experimental investigations, numerical results from RANS simulations with the k-ω-SST turbulence model are presented that were carried out as basis for future investigations on turbulent heat flux modeling.
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Otic´, I., and G. Gro¨tzbach. "Direct Numerical Simulation and RANS Modeling of Turbulent Natural Convection for Low Prandtl Number Fluids." In ASME/JSME 2004 Pressure Vessels and Piping Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/pvp2004-3132.

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Results of direct numerical simulation (DNS) of turbulent Rayleigh-Be´nard convection for a Prandtl number Pr = 0.025 and a Rayleigh number Ra = 105 are used to evaluate the turbulent heat flux and the temperature variance. The DNS evaluated turbulent heat flux is compared with the DNS based results of a standard gradient diffusion turbulent heat flux model and with the DNS based results of a standard algebraic turbulent heat flux model. The influence of the turbulence time scales on the predictions by the standard algebraic heat flux model at these Rayleigh- and Prandtl numbers is investigated. A four equation algebraic turbulent heat flux model based on the transport equations for the turbulent kinetic energy k, for the dissipation of the turbulent kinetic energy ε, for the temperature variance θ2, and for the temperature variance dissipation rate εθ is proposed. This model should be applicable to a wide range of low Prandtl number flows.
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Younis, B. A., B. Weigand, and A. Laqua. "Prediction of Heat Transfer in Turbulent Channel Flow With Spanwise Rotation and Suction/Blowing Through Opposite Walls." In ASME Turbo Expo 2009: Power for Land, Sea, and Air. ASMEDC, 2009. http://dx.doi.org/10.1115/gt2009-59691.

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This paper is concerned with the prediction of heat transfer rates in fully-developed turbulent flows in straight channels with mass transfer by suction and blowing through opposite walls, and with rotation about the spanwise axis. The predictions are based on the solution of the Reynolds-averaged forms of the governing equations using a second-order accurate finite-volume formulation. The effects of turbulence on momentum transport were accounted for by using turbulence closures based on the solution of modeled differential transport equations for the Reynolds stresses. A number of alternative models were assessed. These included a high turbulence Reynolds-number model in which the computationally-efficient ‘wall-function’ approach was used to bridge the near-wall region. As the effects of stabilizing system rotation can cause flow relaminarization, the wall-function approach becomes unreliable and integration must be carried out through the viscous sub-layer, directly to the walls. The suitability of three alternative low Reynolds-number models was assessed in these flows. Experimental data from flows in stationary channels with Reynolds numbers spanning the range of laminar, transitional and turbulent regimes were also used in this assessment. Excellent predictions of the wall skin-friction coefficient across the entire range were obtained with a low Reynolds-number model in which the effects of a rigid wall on the fluctuating pressure field in its vicinity were accounted for by a method which incorporates the gradients of the turbulence length scale and the invariants of turbulence anisotropy. For the cases of heated flows, two very different models for the turbulent heat fluxes were examined: one involved the solution of a differential transport equation for each component of the heat-flux tensor and another in which the heat fluxes were obtained from an explicit algebraic model derived from tensor representation theory. It was found that the two models yielded results that were essentially similar and in close agreement with results from recent Direct Numerical Simulations.
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Kim, Kyoungyoun, and Radhakrishna Sureshkumar. "DNS of Heat Transfer Reduction in Viscoelastic Turbulent Channel Flows." In ASME/JSME/KSME 2015 Joint Fluids Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/ajkfluids2015-25057.

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A direct numerical simulation (DNS) of viscoelastic turbulent channel flow with the FENE-P model was carried out to investigate turbulent heat transfer mechanism of polymer drag-reduced flows. The configuration was a fully-developed turbulent channel flow with uniform heat flux imposed on both walls. The temperature was considered as a passive scalar. The Reynolds number based on the friction velocity (uτ) and channel half height (δ) is 125 and Prandtl number is 5. Consistently with the previous experimental observations, the present DNS results show that the heat-transfer coefficient was reduced at a rate faster than the accompanying drag reduction rate. Statistical quantities such as root-mean-square temperature fluctuations and turbulent heat fluxes were obtained and compared with those of a Newtonian fluid flow. Budget terms of the turbulent heat fluxes were also presented.
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Reports on the topic "Turbulent fluxe"

1

Tanny, Josef, Gabriel Katul, Shabtai Cohen, and Meir Teitel. Application of Turbulent Transport Techniques for Quantifying Whole Canopy Evapotranspiration in Large Agricultural Structures: Measurement and Theory. United States Department of Agriculture, January 2011. http://dx.doi.org/10.32747/2011.7592121.bard.

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Original objectives and revisions The original objectives of this research, as stated in the approved proposal were: 1. To establish guidelines for the use of turbulent transport techniques as accurate and reliable tool for continuous measurements of whole canopy ET and other scalar fluxes (e.g. heat and CO2) in large agricultural structures. 2. To conduct a detailed experimental study of flow patterns and turbulence characteristics in agricultural structures. 3. To derive theoretical models of air flow and scalar fluxes in agricultural structures that can guide the interpretation of TT measurements for a wide range of conditions. All the objectives have been successfully addressed within the project. The only modification was that the study focused on screenhouses only, while it was originally planned to study large greenhouses as well. This was decided due to the large amount of field and theoretical work required to meet the objectives within screenhouses. Background In agricultural structures such as screenhouses and greenhouses, evapotranspiration (ET) is currently measured using lysimeters or sap flow gauges. These measurements provide ET estimates at the single-plant scale that must then be extrapolated, often statistically or empirically, to the whole canopy for irrigation scheduling purposes. On the other hand, turbulent transport techniques, like the eddy covariance, have become the standard for measuring whole canopy evapotranspiration in the open, but their applicability to agricultural structures has not yet been established. The subject of this project is the application of turbulent transport techniques to estimate ET for irrigation scheduling within large agricultural structures. Major conclusions and achievements The major conclusions of this project are: (i) the eddy covariance technique is suitable for reliable measurements of scalar fluxes (e.g., evapotranspiration, sensible heat, CO2) in most types of large screenhouses under all climatic conditions tested. All studies resulted with fair energy balance closures; (ii) comparison between measurements and theory show that the model is capable in reliably predicting the turbulent flow characteristics and surface fluxes within screenhouses; (iii) flow characteristics within the screenhouse, like flux-variance similarity and turbulence intensity were valid for the application of the eddy covariance technique in screenhouses of relatively dilute screens used for moderate shading and wind breaking. In more dense screens, usually used for insect exclusions, development of turbulent conditions was marginal; (iv) installation of the sensors requires that the system’s footprint will be within the limits of the screenhouse under study, as is the case in the open. A footprint model available in the literature was found to be reliable in assessing the footprint under screenhouse conditions. Implications, both scientific and agricultural The study established for the first time, both experimentally and theoretically, the use of the eddy covariance technique for flux measurements within agricultural screenhouses. Such measurements, along with reliable theoretical models, will enable more accurate assessments of crop water use which may lead to improved crop water management and increased water use efficiency of screenhouse crops.
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Moum, James N. Turbulence Fluxes. Fort Belvoir, VA: Defense Technical Information Center, January 1996. http://dx.doi.org/10.21236/ada329288.

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Hollenberg, J. B., and J. D. Callen. Turbulent transport across invariant canonical flux surfaces. Office of Scientific and Technical Information (OSTI), July 1994. http://dx.doi.org/10.2172/10185803.

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Tanny, Josef, Gabriel Katul, Shabtai Cohen, and Meir Teitel. Micrometeorological methods for inferring whole canopy evapotranspiration in large agricultural structures: measurements and modeling. United States Department of Agriculture, October 2015. http://dx.doi.org/10.32747/2015.7594402.bard.

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Original objectives and revisions The original objectives as stated in the approved proposal were: (1) To establish guidelines for the use of micrometeorological techniques as accurate, reliable and low-cost tools for continuous monitoring of whole canopy ET of common crops grown in large agricultural structures. (2) To adapt existing methods for protected cultivation environments. (3) To combine previously derived theoretical models of air flow and scalar fluxes in large agricultural structures (an outcome of our previous BARD project) with ET data derived from application of turbulent transport techniques for different crops and structure types. All the objectives have been successfully addressed. The study was focused on both screenhouses and naturally ventilated greenhouses, and all proposed methods were examined. Background to the topic Our previous BARD project established that the eddy covariance (EC) technique is suitable for whole canopy evapotranspiration measurements in large agricultural screenhouses. Nevertheless, the eddy covariance technique remains difficult to apply in the farm due to costs, operational complexity, and post-processing of data – thereby inviting alternative techniques to be developed. The subject of this project was: 1) the evaluation of four turbulent transport (TT) techniques, namely, Surface Renewal (SR), Flux-Variance (FV), Half-order Time Derivative (HTD) and Bowen Ratio (BR), whose instrumentation needs and operational demands are not as elaborate as the EC, to estimate evapotranspiration within large agricultural structures; and 2) the development of mathematical models able to predict water savings and account for the external environmental conditions, physiological properties of the plant, and structure properties as well as to evaluate the necessary micrometeorological conditions for utilizing the above turbulent transfer methods in such protected environments. Major conclusions and achievements The major conclusions are: (i) the SR and FV techniques were suitable for reliable estimates of ET in shading and insect-proof screenhouses; (ii) The BR technique was reliable in shading screenhouses; (iii) HTD provided reasonable results in the shading and insect proof screenhouses; (iv) Quality control analysis of the EC method showed that conditions in the shading and insect proof screenhouses were reasonable for flux measurements. However, in the plastic covered greenhouse energy balance closure was poor. Therefore, the alternative methods could not be analyzed in the greenhouse; (v) A multi-layered flux footprint model was developed for a ‘generic’ crop canopy situated within a protected environment such as a large screenhouse. The new model accounts for the vertically distributed sources and sinks within the canopy volume as well as for modifications introduced by the screen on the flow field and microenvironment. The effect of the screen on fetch as a function of its relative height above the canopy is then studied for the first time and compared to the case where the screen is absent. The model calculations agreed with field experiments based on EC measurements from two screenhouse experiments. Implications, both scientific and agricultural The study established for the first time, both experimentally and theoretically, the use of four simple TT techniques for ET estimates within large agricultural screenhouses. Such measurements, along with reliable theoretical models, will enable the future development of lowcost ET monitoring system which will be attainable for day-to-day use by growers in improving irrigation management.
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Trowbridge, J. H., and A. J. Williams. Measurement of Turbulent Fluxes and Dissipation Rates in the Coastal Bottom Boundary Layer. Fort Belvoir, VA: Defense Technical Information Center, September 1997. http://dx.doi.org/10.21236/ada628740.

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Ku, S., P. H. Dimond, G. Dif-Pradalier, J. M. Kwon, Y. Sarazin, T. S. Hahm, X. Garbet, et al. Physics of Intrinsic Rotation in Flux-Driven ITG Turbulence. Office of Scientific and Technical Information (OSTI), February 2012. http://dx.doi.org/10.2172/1035870.

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Koseff, Jeffrey R., Joel H. Ferziger, and Stephen G. Monismith. Turbulence Modeling in Stratified Flows Subject to Advective Buoyancy Fluxes. Fort Belvoir, VA: Defense Technical Information Center, September 2003. http://dx.doi.org/10.21236/ada618364.

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Kalogiros, Ioannis. Understanding Near-Surface and In-Cloud Turbulent Fluxes in the Coastal Stratocumulus-Topped Boundary Layers. Fort Belvoir, VA: Defense Technical Information Center, October 2004. http://dx.doi.org/10.21236/ada428722.

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Wang, Qing. Understanding Near-surface and In-cloud Turbulent Fluxes in the Coastal Stratocumulus-Topped Boundary Layers. Fort Belvoir, VA: Defense Technical Information Center, September 2007. http://dx.doi.org/10.21236/ada541545.

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Wang, Qing. Understanding Near-Surface and In-cloud Turbulent Fluxes in the Coastal Stratocumulus-topped Boundary Layers. Fort Belvoir, VA: Defense Technical Information Center, September 2003. http://dx.doi.org/10.21236/ada629627.

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