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Статті в журналах з теми "Turbulence Closures"

Автор: Grafiati

Опубліковано: 11 березня 2023

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1

Pearson, Brodie C., Alan L. M. Grant, and Jeff A. Polton. "Pressure–strain terms in Langmuir turbulence." Journal of Fluid Mechanics 880 (October 7, 2019): 5–31. http://dx.doi.org/10.1017/jfm.2019.701.

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This study investigates the pressure–strain tensor ($\unicode[STIX]{x1D72B}$) in Langmuir turbulence. The pressure–strain tensor is determined from large-eddy simulations (LES), and is partitioned into components associated with the mean current shear (rapid), the Stokes shear and the turbulent–turbulent (slow) interactions. The rapid component can be parameterized using existing closure models, although the coefficients in the closure models are particular to Langmuir turbulence. A closure model for the Stokes component is proposed, and it is shown to agree with results from the LES. The slow

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2

Larsen, Bjarke Eltard, and David R. Fuhrman. "On the over-production of turbulence beneath surface waves in Reynolds-averaged Navier–Stokes models." Journal of Fluid Mechanics 853 (August 23, 2018): 419–60. http://dx.doi.org/10.1017/jfm.2018.577.

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In previous computational fluid dynamics studies of breaking waves, there has been a marked tendency to severely over-estimate turbulence levels, both pre- and post-breaking. This problem is most likely related to the previously described (though not sufficiently well recognized) conditional instability of widely used turbulence models when used to close Reynolds-averaged Navier–Stokes (RANS) equations in regions of nearly potential flow with finite strain, resulting in exponential growth of the turbulent kinetic energy and eddy viscosity. While this problem has been known for nearly 20 years,

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3

Gladskikh, Daria, Lev Ostrovsky, Yuliya Troitskaya, Irina Soustova, and Evgeny Mortikov. "Turbulent Transport in a Stratified Shear Flow." Journal of Marine Science and Engineering 11, no. 1 (2023): 136. http://dx.doi.org/10.3390/jmse11010136.

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Within the framework of the theory of unsteady turbulent flows in a stratified fluid, a new parameterization of the turbulent Prandtl number is proposed. The parameterization is included in the k-ε-closure and used within the three-dimensional model of thermohydrodynamics of an enclosed water body where density distribution includes pycnocline. This allows us to describe turbulence in a stratified shear flow without the restrictions associated with the gradient Richardson number and justify the choice of closure constants. Numerical experiments, where the downward penetration of turbulence was

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4

Mauritsen, Thorsten, Gunilla Svensson, Sergej S. Zilitinkevich, Igor Esau, Leif Enger, and Branko Grisogono. "A Total Turbulent Energy Closure Model for Neutrally and Stably Stratified Atmospheric Boundary Layers." Journal of the Atmospheric Sciences 64, no. 11 (2007): 4113–26. http://dx.doi.org/10.1175/2007jas2294.1.

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Abstract This paper presents a turbulence closure for neutral and stratified atmospheric conditions. The closure is based on the concept of the total turbulent energy. The total turbulent energy is the sum of the turbulent kinetic energy and turbulent potential energy, which is proportional to the potential temperature variance. The closure uses recent observational findings to take into account the mean flow stability. These observations indicate that turbulent transfer of heat and momentum behaves differently under very stable stratification. Whereas the turbulent heat flux tends toward zero

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5

Harcourt, Ramsey R. "An Improved Second-Moment Closure Model of Langmuir Turbulence." Journal of Physical Oceanography 45, no. 1 (2015): 84–103. http://dx.doi.org/10.1175/jpo-d-14-0046.1.

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AbstractA prior second-moment closure (SMC) model of Langmuir turbulence in the upper ocean is modified by introduction of inhomogeneous pressure–strain rate and pressure–scalar gradient closures that are similar to the high Reynolds number, near-wall treatments for solid wall boundaries. This repairs several near-surface defects in the algebraic Reynolds stress model (ARSM) of the prior SMC by redirecting Craik–Leibovich (CL) vortex force production of turbulent kinetic energy out of the surface-normal vertical component and into a horizontal one, with an associated reduction in near-surface

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6

Mortikov, E. V., A. V. Glazunov, A. V. Debolskiy, V. N. Lykosov, and S. S. Zilitinkevich. "On the modelling of the dissipation rate of turbulent kinetic energy." Доклады Академии наук 489, no. 4 (2019): 414–18. http://dx.doi.org/10.31857/s0869-56524894414-418.

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We consider a relaxation equation for turbulence wavenumber for use in semi-empirical turbulence closures. It is shown that the well-known phenomenological equation for the dissipation rate of turbulent kinetic energy can be related to this relaxation equation as a close approximation of the latter for stably stratified quasi-stationary flows. The proposed approach allows for more physically found definition of the empirical constants and improvement of atmospheric and oceanic boundary layer turbulence closures by using direct numerical and large eddy simulation data to define equilibrium stat

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7

GODEFERD, F. S., C. CAMBON, and J. F. SCOTT. "Two-point closures and their applications: report on a workshop." Journal of Fluid Mechanics 436 (June 10, 2001): 393–407. http://dx.doi.org/10.1017/s0022112001004359.

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This international scientific workshop was organized in Lyon, France, from 10 to 12 May 2000. Its focus was ‘Two-point closures and their applications’, with the understanding that the analysis and design of such models requires expert knowledge coming from a wide range of areas in turbulence research, e.g. experiments, numerical simulations, asymptotic models, etc.In the global challenge of turbulence modelling, two-point closures prove useful in many ways. Two-point correlations and spectra are useful measures of the distortion of the eddy structure of turbulence by stratification, large-sca

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8

Yang, S. L., B. D. Peschke, and K. Hanjalic. "Second-Moment Closure Model for IC Engine Flow Simulation Using Kiva Code1." Journal of Engineering for Gas Turbines and Power 122, no. 2 (1999): 355–63. http://dx.doi.org/10.1115/1.483213.

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The flow and turbulence in an IC engine cylinder were studied using the SSG variant of the Reynolds stress turbulence closure model. In-cylinder turbulence is characterized by strong turbulence anisotropy and flow rotation, which aid in air-fuel mixing. It is argued that solving the differential transport equations for each turbulent stress tensor component, as implied by second-moment closures, can better reproduce stress anisotropy and effects of rotation, than with eddy-viscosity models. Therefore, a Reynolds stress model that can meet the demands of in-cylinder flows was incorporated into

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9

Pacciani, Roberto, Michele Marconcini, Francesco Bertini, et al. "Assessment of Machine-Learned Turbulence Models Trained for Improved Wake-Mixing in Low-Pressure Turbine Flows." Energies 14, no. 24 (2021): 8327. http://dx.doi.org/10.3390/en14248327.

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This paper presents an assessment of machine-learned turbulence closures, trained for improving wake-mixing prediction, in the context of LPT flows. To this end, a three-dimensional cascade of industrial relevance, representative of modern LPT bladings, was analyzed, using a state-of-the-art RANS approach, over a wide range of Reynolds numbers. To ensure that the wake originates from correctly reproduced blade boundary-layers, preliminary analyses were carried out to check for the impact of transition closures, and the best-performing numerical setup was identified. Two different machine-learn

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10

Frederiksen, Jorgen S., and Terence J. O’Kane. "Statistical Dynamics of Mean Flows Interacting with Rossby Waves, Turbulence, and Topography." Fluids 7, no. 6 (2022): 200. http://dx.doi.org/10.3390/fluids7060200.

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Abridged statistical dynamical closures, for the interaction of two-dimensional inhomogeneous turbulent flows with topography and Rossby waves on a beta–plane, are formulated from the Quasi-diagonal Direct Interaction Approximation (QDIA) theory, at various levels of simplification. An abridged QDIA is obtained by replacing the mean field trajectory, from initial-time to current-time, in the time history integrals of the non-Markovian closure by the current-time mean field. Three variants of Markovian Inhomogeneous Closures (MICs) are formulated from the abridged QDIA by using the current-time

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11

Kurowski, Marcin J., and João Teixeira. "A Scale-Adaptive Turbulent Kinetic Energy Closure for the Dry Convective Boundary Layer." Journal of the Atmospheric Sciences 75, no. 2 (2018): 675–90. http://dx.doi.org/10.1175/jas-d-16-0296.1.

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Abstract A pragmatic scale-adaptive turbulent kinetic energy (TKE) closure is proposed to simulate the dry convective boundary layer for a variety of horizontal grid resolutions: from 50 m, typical of large-eddy simulation models that use three-dimensional turbulence parameterizations/closures, up to 100 km, typical of climate models that use one-dimensional turbulence and convection parameterizations/closures. Since parameterizations/closures using the TKE approach have been frequently used in these two asymptotic limits, a simple method is proposed to merge them with a mixing-length-scale fo

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12

Lin, F. B., and F. Sotiropoulos. "Strongly-Coupled Multigrid Method for 3-D Incompressible Flows Using Near-Wall Turbulence Closures." Journal of Fluids Engineering 119, no. 2 (1997): 314–24. http://dx.doi.org/10.1115/1.2819136.

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An efficient artificial compressibility algorithm is developed for solving the three-dimensional Reynolds-averaged Navier-Stokes equations in conjunction with the low-Reynolds number k-ω turbulence model (Wilcox, 1994). Two second-order accurate central-differencing schemes, with scalar and matrix-valued artificial dissipation, respectively, and a third-order accurate flux-difference splitting upwind scheme are implemented for discretizing the convective terms. The discrete equations are integrated in time using a Runge-Kutta algorithm enhanced with local time stepping, implicit residual smoot

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13

Yoo, G. J., R. M. C. So, and B. C. Hwang. "Calculation of Developing Turbulent Flows in a Rotating Pipe." Journal of Turbomachinery 113, no. 1 (1991): 34–41. http://dx.doi.org/10.1115/1.2927735.

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Internal rotating boundary-layer flows are strongly influenced by large circumferential strain and the turbulence field is anisotropic. This is especially true in the entry region of a rotating pipe where the flow is three dimensional, the centrifugal force due to fluid rotation is less important, and the circumferential strain created by surface rotation has a significant effect on the turbulence field near the wall. Consequently, viscous effects cannot be neglected in the near-wall region. Several low-Reynolds-number turbulence closures are proposed for the calculation of developing rotating

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14

de Divitiis, Nicola. "Statistical Lyapunov Theory Based on Bifurcation Analysis of Energy Cascade in Isotropic Homogeneous Turbulence: A Physical–Mathematical Review." Entropy 21, no. 5 (2019): 520. http://dx.doi.org/10.3390/e21050520.

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This work presents a review of previous articles dealing with an original turbulence theory proposed by the author and provides new theoretical insights into some related issues. The new theoretical procedures and methodological approaches confirm and corroborate the previous results. These articles study the regime of homogeneous isotropic turbulence for incompressible fluids and propose theoretical approaches based on a specific Lyapunov theory for determining the closures of the von Kármán–Howarth and Corrsin equations and the statistics of velocity and temperature difference. While numerou

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15

Yu, Li-ren, and Jun Yu. "ENVIRONMENTAL FLOW AND CONTAMINANT TRANSPORT MODELING IN THE AMAZONIAN WATER SYSTEM BY USING Q3DRM1.0 SOFTWARE." International Journal of Research -GRANTHAALAYAH 5, no. 12 (2020): 377–91. http://dx.doi.org/10.29121/granthaalayah.v5.i12.2017.525.

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This paper reports a fine numerical simulation of environmental flow and contaminant transport in the Amazonian water system near the Anamã City, Brazil, solved by the Q3drm1.0 software, developed by the Authors, which can provide the different closures of three depth-integrated two-equation turbulence models. The purpose of this simulation is to refinedly debug and test the developed software, including the mathematical model, turbulence closure models, adopted algorithms, and the developed general-purpose computational codes as well as graphical user interfaces (GUI). The three turbulence mo

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16

Yan, Chao, and James G. McDonald. "Hyperbolic turbulence models for moment closures." Journal of Computational Physics 422 (December 2020): 109753. http://dx.doi.org/10.1016/j.jcp.2020.109753.

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17

Fitch, A. C. "An Improved Double-Gaussian Closure for the Subgrid Vertical Velocity Probability Distribution Function." Journal of the Atmospheric Sciences 76, no. 1 (2019): 285–304. http://dx.doi.org/10.1175/jas-d-18-0149.1.

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Abstract The vertical velocity probability distribution function (PDF) is analyzed throughout the depth of the lower atmosphere, including the subcloud and cloud layers, in four large-eddy simulation (LES) cases of shallow cumulus and stratocumulus. Double-Gaussian PDF closures are examined to test their ability to represent a wide range of turbulence statistics, from stratocumulus cloud layers characterized by Gaussian turbulence to shallow cumulus cloud layers displaying strongly non-Gaussian turbulence statistics. While the majority of the model closures are found to perform well in the for

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18

Frederiksen, Jorgen S., and Terence J. O’Kane. "Markovian inhomogeneous closures for Rossby waves and turbulence over topography." Journal of Fluid Mechanics 858 (October 31, 2018): 45–70. http://dx.doi.org/10.1017/jfm.2018.784.

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Manifestly Markovian closures for the interaction of two-dimensional inhomogeneous turbulent flows with Rossby waves and topography are formulated and compared with large ensembles of direct numerical simulations (DNS) on a generalized $\unicode[STIX]{x1D6FD}$-plane. Three versions of the Markovian inhomogeneous closure (MIC) are established from the quasi-diagonal direct interaction approximation (QDIA) theory by modifying the response function to a Markovian form and employing respectively the current-time (quasi-stationary) fluctuation dissipation theorem (FDT), the prior-time (non-stationa

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19

Fisher, Alexander W., Lawrence P. Sanford, and Malcolm E. Scully. "Wind-Wave Effects on Estuarine Turbulence: A Comparison of Observations and Second-Moment Closure Predictions." Journal of Physical Oceanography 48, no. 4 (2018): 905–23. http://dx.doi.org/10.1175/jpo-d-17-0133.1.

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AbstractObservations of turbulent kinetic energy, dissipation, and turbulent stress were collected in the middle reaches of Chesapeake Bay and were used to assess second-moment closure predictions of turbulence generated beneath breaking waves. Dissipation scaling indicates that the turbulent flow structure observed during a 10-day wind event was dominated by a three-layer response that consisted of 1) a wave transport layer, 2) a surface log layer, and 3) a tidal, bottom boundary layer limited by stable stratification. Below the wave transport layer, turbulent mixing was limited by stable str

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20

Borello, Domenico, Kemal Hanjalic, and Franco Rispoli. "Prediction of Cascade Flows With Innovative Second-Moment Closures." Journal of Fluids Engineering 127, no. 6 (2005): 1059–70. http://dx.doi.org/10.1115/1.2073267.

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We report on the performances of two second-moment turbulence closures in predicting turbulence and laminar-to-turbulent transition in turbomachinery flows. The first model considered is the one by Hanjalic and Jakirlic (HJ) [Comput. Fluids, 27(2), pp. 137–156 (1998)], which follows the conventional approach with damping functions to account for the wall viscous and nonviscous effect. The second is an innovative topology-free elliptic blending model, EBM [R. Manceau and K. Hanjalic, Phys. Fluids, 14(3), pp. 1–11 (2002)], here presented in a revised formulation. An in-house finite element code

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21

Umlauf, Lars. "The Description of Mixing in Stratified Layers without Shear in Large-Scale Ocean Models." Journal of Physical Oceanography 39, no. 11 (2009): 3032–39. http://dx.doi.org/10.1175/2009jpo4006.1.

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Abstract Large-scale geophysical flows often exhibit layers with negligible vertical shear and infinite gradient Richardson number Ri. It is well known that these layers may be regions of active mixing, even in the absence of local shear production of turbulence because, among other processes, turbulence may be supplied by vertical turbulent transport from neighboring regions. This observation is contrasted by the behavior of most turbulence parameterizations used in ocean climate modeling, predicting the collapse of mixing of mass and matter if the Richardson number exceeds a critical thresho

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22

BROCCHINI, M., and D. H. PEREGRINE. "The dynamics of strong turbulence at free surfaces. Part 2. Free-surface boundary conditions." Journal of Fluid Mechanics 449 (December 12, 2001): 255–90. http://dx.doi.org/10.1017/s0022112001006024.

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Strong turbulence at a water–air free surface can lead to splashing and a disconnected surface as in a breaking wave. Averaging to obtain boundary conditions for such flows first requires equations of motion for the two-phase region. These are derived using an integral method, then averaged conservation equations for mass and momentum are obtained along with an equation for the turbulent kinetic energy in which extra work terms appear. These extra terms include both the mean pressure and the mean rate of strain and have similarities to those for a compressible fluid. Boundary conditions approp

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23

Zhou, Bowen, and Fotini Katopodes Chow. "Nested Large-Eddy Simulations of the Intermittently Turbulent Stable Atmospheric Boundary Layer over Real Terrain." Journal of the Atmospheric Sciences 71, no. 3 (2014): 1021–39. http://dx.doi.org/10.1175/jas-d-13-0168.1.

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Abstract The nighttime stable atmospheric boundary layer over real terrain is modeled with nested high-resolution large-eddy simulations (LESs). The field site is located near Leon, Kansas, where the 1999 Cooperative Atmosphere–Surface Exchange Study took place. The terrain is mostly flat with an average slope of 0.5°. The main topographic feature is a shallow valley oriented in the east–west direction. The night of 5 October is selected to study intermittent turbulence under prevailing quiescent conditions. Brief turbulent periods triggered by shear-instability waves are modeled with good mag

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24

Lai, Y. G., R. M. C. So, M. Anwer, and B. C. Hwang. "Calculations of a Curved-Pipe Flow Using Reynolds Stress Closure." Proceedings of the Institution of Mechanical Engineers, Part C: Mechanical Engineering Science 205, no. 4 (1991): 231–44. http://dx.doi.org/10.1243/pime_proc_1991_205_115_02.

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It has been observed that as a fully developed turbulent flow enters a curved bend the anisotropy of the normal stresses near the outer bend (furthest from the centre of the bend curvature) increases. According to the arguments of vorticity generation, a sudden increase in the anisotropy of the normal stresses may lead to the formation of a secondary flow of the second kind. If this secondary motion is to be calculated, then a near-wall Reynolds stress closure that can mimic the anisotropic turbulence behaviour near a wall has to be used. This study presents the results of just such an attempt

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25

Bertoglio, Jean-Pierre, Françoise Bataille, and Jean-Denis Marion. "Two-point closures for weakly compressible turbulence." Physics of Fluids 13, no. 1 (2001): 290–310. http://dx.doi.org/10.1063/1.1324005.

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26

Elkhoury, M. "Assessment and Modification of One-Equation Models of Turbulence for Wall-Bounded Flows." Journal of Fluids Engineering 129, no. 7 (2007): 921–28. http://dx.doi.org/10.1115/1.2743666.

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This work assesses the performance of two single-equation eddy viscosity transport models that are based on Menter’s transformation of the k-ε and the k-ω closures. The coefficients of both models are set exactly the same and follow directly from the constants of the standard k-ε closure. This in turn allows a cross-comparison of the effect of two different destruction terms on the performance of single-equation closures. Furthermore, some wall-free modifications to production and destruction terms are proposed and applied to both models. An assessment of the baseline models with and without t

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27

Fu, S., P. G. Huang, B. E. Launder, and M. A. Leschziner. "A Comparison of Algebraic and Differential Second-Moment Closures for Axisymmetric Turbulent Shear Flows With and Without Swirl." Journal of Fluids Engineering 110, no. 2 (1988): 216–21. http://dx.doi.org/10.1115/1.3243537.

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Computations are reported for three axisymmetric turbulent jets, two of which are swirling and one containing swirl-induced recirculation, obtained with two models of turbulence: a differential second-moment (DSM) closure and an algebraic derivative thereof (ASM). The models are identical in respect of all turbulent processes except that, in the ASM scheme, stress transport is represented algebraically in terms of the transport of turbulence energy. The comparison of the results thus provides a direct test of how well the model of stress transport adopted in ASM schemes simulates that of the f

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28

Mishra, Aashwin A., and Sharath S. Girimaji. "Intercomponent energy transfer in incompressible homogeneous turbulence: multi-point physics and amenability to one-point closures." Journal of Fluid Mechanics 731 (August 28, 2013): 639–81. http://dx.doi.org/10.1017/jfm.2013.343.

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AbstractIntercomponent energy transfer (IET) is a direct consequence of the incompressibility-preserving action of pressure. This action of pressure is inherently non-local, and consequently its modelling must address multi-point physics. However, in second moment closures, pragmatism mandates a single-point closure model for the pressure–strain correlation, that is, the source of IET. In this study, we perform a rapid distortion analysis to demonstrate that for a given mean-flow gradient, IET is strongly dependent on fluctuation modes and critically influences the flow stability, asymptotic s

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29

SEENI, Aravind. "Effect of Turbulence Models in Performance Characterization of a Low Reynolds Number UAV Propeller." INCAS BULLETIN 13, no. 4 (2021): 151–66. http://dx.doi.org/10.13111/2066-8201.2021.13.4.13.

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The advancement of computer technology has given the necessary impetus to perform numerical modelling and simulation in engineering. Turbulence modelling in Computational Fluid Dynamics is characterized by non-physics based modelling and there are several developments in this area that also has contributed to the growing rise in empiricism. Typically, turbulence models are chosen based on expert knowledge and experience. In this paper, the problem of selecting a turbulence closure is addressed for a small Unmanned Aerial Vehicle propeller rotating at a low Reynolds number. Using scientific app

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30

Straatman, Anthony G. "A Modified Model for Diffusion in Second-Moment Turbulence Closures." Journal of Fluids Engineering 121, no. 4 (1999): 747–56. http://dx.doi.org/10.1115/1.2823532.

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A study has been carried out to determine the relative roles of the three diffusion sub-processes contained in the Lumley (1978) diffusion model. The three sub-processes are described as being the production of turbulent transport, the third-order pressure-velocity process, which regulates the relative magnitudes of the turbulent transport components, and the pressure-diffusion. The present work describes a unique method for calibrating the model based on an analysis of zero-mean-shear turbulence. On the basis of the analysis, and using recent direct numerical simulation and experimental data,

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31

Larson, Vincent E., and Jean-Christophe Golaz. "Using Probability Density Functions to Derive Consistent Closure Relationships among Higher-Order Moments." Monthly Weather Review 133, no. 4 (2005): 1023–42. http://dx.doi.org/10.1175/mwr2902.1.

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Parameterizations of turbulence often predict several lower-order moments and make closure assumptions for higher-order moments. In principle, the low- and high-order moments share the same probability density function (PDF). One closure assumption, then, is the shape of this family of PDFs. When the higher-order moments involve both velocity and thermodynamic scalars, often the PDF shape has been assumed to be a double or triple delta function. This is equivalent to assuming a mass-flux model with no subplume variability. However, PDF families other than delta functions can be assumed. This i

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32

Fiori, Elisabetta, Antonio Parodi, and Franco Siccardi. "Turbulence Closure Parameterization and Grid Spacing Effects in Simulated Supercell Storms." Journal of the Atmospheric Sciences 67, no. 12 (2010): 3870–90. http://dx.doi.org/10.1175/2010jas3359.1.

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Abstract Many meteorological organizations plan to substantially increase the resolution of the limited-area models used for severe weather prediction. Such an approach does not guarantee a priori the reduction of the uncertainty of the decision maker in the prediction of severe weather impact. A deep moist convective process, a supercell, is studied in a simplified atmospheric scenario by means of high-resolution numerical simulations with the Consortium for Small-Scale Modeling (COSMO) model. Different turbulence closure models and their impact on the spatiotemporal properties of storm proce

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33

Viollet, P. L., and O. Simonin. "Modelling Dispersed Two-Phase Flows: Closure, Validation and Software Development." Applied Mechanics Reviews 47, no. 6S (1994): S80—S84. http://dx.doi.org/10.1115/1.3124445.

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Closure for the Eulerian modelling of two-phase flows have been developed, based upon extensions of the theory of Tchen of the dispersion of particles in homogeneous turbulence. This model has been validated using large-eddy simulation of homogeneous turbulence, jets loaded with particles, and bubbly flows. In addition with k-epsilon model for the continuous phase, and closures for the Reynolds stresses of the dispersed phase, this theory has been implemented in 2D and 3D software solving the Eulerian two-phase equations (Me´lodif in 2D, as a research code, and ESTET-ASTRID in 3D). These softw

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34

Abou-Arab, T. W., and M. C. Roco. "Solid Phase Contribution in the Two-Phase Turbulence Kinetic Energy Equation." Journal of Fluids Engineering 112, no. 3 (1990): 351–61. http://dx.doi.org/10.1115/1.2909411.

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This paper presents a multiphase turbulence closure employing one transport equation, namely, the turbulence kinetic energy equation. The proposed form of this equation is different from the earlier formulations in some aspects. The power spectrum of the carrier fluid is divided into two regions, which interact in different ways and at different rates with the suspended particles as a function of the particle-eddy size ratio and density ratio. The length scale is described algebraically. A double-time averaging approach for the momentum and kinetic energy equations is adopted. The resulting tu

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35

Chaibina, F., G. Bellakhal, and J. Chahed. "First and Second Order Turbulence Closures Applied to Homogeneous Turbulent Bubbly Flows." Journal of Applied Fluid Mechanics 12, no. 6 (2019): 1813–23. http://dx.doi.org/10.29252/jafm.12.06.29756.

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36

Zhou, Ye, and George Vahala. "Aspects of subgrid modelling and large-eddy simulation of magnetohydrodynamic turbulence." Journal of Plasma Physics 45, no. 2 (1991): 239–49. http://dx.doi.org/10.1017/s0022377800015671.

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Subgrid-scale closures for magnetohydodynamic (MHD) turbulence are examined using the filtering technique. From the similarities between incompressible MHD turbulence and its hydrodynamic counterpart, as well as ideas from dynamo theory, a subgrid model is constructed from the large-eddy simulation (LES) of MHD turbulence. This model should find applicability in treating LES of the reversed-field pinch.

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37

Tjernström, Michael, Ben B. Balsley, Gunilla Svensson, and Carmen J. Nappo. "The Effects of Critical Layers on Residual Layer Turbulence." Journal of the Atmospheric Sciences 66, no. 2 (2009): 468–80. http://dx.doi.org/10.1175/2008jas2729.1.

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Abstract The authors report results of a study of finescale turbulence structure in the portion of the nocturnal boundary layer known as the residual layer (RL). The study covers two nights during the Cooperative Atmosphere–Surface Exchange Study 1999 (CASES-99) field experiment that exhibit significant differences in turbulence, as indicated by the observed turbulence dissipation rates in the RL. The RL turbulence sometimes reaches intensities comparable to those in the underlying stable boundary layer. The commonly accepted concept of turbulence generation below critical values of the gradie

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38

Batten, Paul, Uriel Goldberg, and Sukumar Chakravarthy. "Interfacing Statistical Turbulence Closures with Large-Eddy Simulation." AIAA Journal 42, no. 3 (2004): 485–92. http://dx.doi.org/10.2514/1.3496.

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39

So, R. M. C., Y. G. Lai, H. S. Zhang, and B. C. Hwang. "Second-order near-wall turbulence closures - A review." AIAA Journal 29, no. 11 (1991): 1819–35. http://dx.doi.org/10.2514/3.10807.

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40

Younis, Bassam A., and Ye Zhou. "Accounting for mean-flow periodicity in turbulence closures." Physics of Fluids 18, no. 1 (2006): 018102. http://dx.doi.org/10.1063/1.2166458.

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41

Rubinstein, Robert, and Timothy T. Clark. "Reassessment of the classical closures for scalar turbulence." Journal of Turbulence 14, no. 2 (2013): 71–98. http://dx.doi.org/10.1080/14685248.2013.769685.

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42

Speziale, Charles G., Ridha Abid, and Paul A. Durbin. "On the realizability of reynolds stress turbulence closures." Journal of Scientific Computing 9, no. 4 (1994): 369–403. http://dx.doi.org/10.1007/bf01575099.

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43

Maulik, Romit, and Omer San. "Explicit and implicit LES closures for Burgers turbulence." Journal of Computational and Applied Mathematics 327 (January 2018): 12–40. http://dx.doi.org/10.1016/j.cam.2017.06.003.

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44

Duvigneau, Régis, Jérémie Labroquère, and Emmanuel Guilmineau. "Comparison of turbulence closures for optimized active control." Computers & Fluids 124 (January 2016): 67–77. http://dx.doi.org/10.1016/j.compfluid.2015.10.011.

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45

Speziale, Charles G., and Nessan Mac Giolla Mhuiris. "On the prediction of equilibrium states in homogeneous turbulence." Journal of Fluid Mechanics 209 (December 1989): 591–615. http://dx.doi.org/10.1017/s002211208900323x.

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A comparison of several commonly used turbulence models (including the K–ε model and three second-order closures) is made for the test problem of homogeneous turbulent shear flow in a rotating frame. The time evolution of the turbulent kinetic energy and dissipation rate is calculated for these models and comparisons are made with previously published experiments and numerical simulations. Particular emphasis is placed on examining the ability of each model to predict equilibrium states accurately for a range of the parameter Ω/S (the ratio of the rotation rate to the shear rate). It is found

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46

Lance, M., J. L. Marie´, and J. Bataille. "Homogeneous Turbulence in Bubbly Flows." Journal of Fluids Engineering 113, no. 2 (1991): 295–300. http://dx.doi.org/10.1115/1.2909495.

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The present study is devoted to the interaction between a swarm of bubbles and a turbulent field in a linear shear flow. The transversal and longitudinal evolutions of the void fraction and of the Reynolds stress tensor have been measured. When the air bubbles are blown uniformly into the shear, the void fraction profiles exhibit a strong gradient which can be explained by kinematical effects. No void migration has been observed. The behavior of the Reynolds tensor indicates that the nonisotropy induced by the mean velocity gradient decreases when the void fraction increases. A simple mechanis

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47

Rani, Sarma L., Vijay K. Gupta, and Donald L. Koch. "Clustering of rapidly settling, low-inertia particle pairs in isotropic turbulence. Part 1. Drift and diffusion flux closures." Journal of Fluid Mechanics 871 (May 22, 2019): 450–76. http://dx.doi.org/10.1017/jfm.2019.204.

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In this two-part study, we present the development and analysis of a stochastic theory for characterizing the relative positions of monodisperse, low-inertia particle pairs that are settling rapidly in homogeneous isotropic turbulence. In the limits of small Stokes number and Froude number such that $Fr\ll St_{\unicode[STIX]{x1D702}}\ll 1$, closures are developed for the drift and diffusion fluxes in the probability density function (p.d.f.) equation for the pair relative positions. The theory focuses on the relative motion of particle pairs in the dissipation regime of turbulence, i.e. for pa

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48

SPEZIALE, C. G., B. A. YOUNIS, and S. A. BERGER. "Analysis and modelling of turbulent flow in an axially rotating pipe." Journal of Fluid Mechanics 407 (March 25, 2000): 1–26. http://dx.doi.org/10.1017/s0022112099007600.

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The analysis and modelling of the structure of turbulent flow in a circular pipe subjected to an axial rotation is presented. Particular attention is paid to determining the terms in various turbulence closures that generate the two main physical features that characterize this flow: a rotationally dependent axial mean velocity and a rotationally dependent mean azimuthal or swirl velocity relative to the rotating pipe. It is shown that the first feature is well represented by two-dimensional explicit algebraic stress models but is irreproducible by traditional two-equation models. On the other

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49

Dussauge, J. P., and J. Gaviglio. "The rapid expansion of a supersonic turbulent flow: role of bulk dilatation." Journal of Fluid Mechanics 174 (January 1987): 81–112. http://dx.doi.org/10.1017/s0022112087000053.

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The rapid expansion of a turbulent boundary layer in supersonic flow is studied analytically and experimentally. Emphasis is placed on the effect of bulk dilatation on turbulent fluctuations. The hypotheses made in the analysis are similar to those in the rapid distortion theory and are used to simplify second-order closures. By assuming that the fluctuating velocity is solenoidal an extension of classical subsonic models is proposed. A new variable is defined, which takes into account the mean density variations, and behaves like the Reynolds stress tensor in subsonic flows with weak inhomoge

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50

McTaggart-Cowan, Ron, and Ayrton Zadra. "Representing Richardson Number Hysteresis in the NWP Boundary Layer." Monthly Weather Review 143, no. 4 (2015): 1232–58. http://dx.doi.org/10.1175/mwr-d-14-00179.1.

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Abstract Turbulence in the planetary boundary layer (PBL) transports heat, momentum, and moisture in eddies that are not resolvable by current NWP systems. Numerical models typically parameterize this process using vertical diffusion operators whose coefficients depend on the intensity of the expected turbulence. The PBL scheme employed in this study uses a one-and-a-half-order closure based on a predictive equation for the turbulent kinetic energy (TKE). For a stably stratified fluid, the growth and decay of TKE is largely controlled by the dynamic stability of the flow as represented by the

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