Article
Computer Science, Interdisciplinary Applications
Y. Kuwata, K. Suga
Summary: A novel implementation route of the wall-function method to the lattice Boltzmann method is proposed for extending the LBM applicability in high Reynolds number turbulent heat transfer in complex geometries. The developed method shows capability to handle complex curvilinear walls and yield grid independent solution with satisfactory accuracy. It has great potential in predicting high Prandtl number flows under partially to highly underresolved conditions.
JOURNAL OF COMPUTATIONAL PHYSICS
(2021)
Article
Engineering, Aerospace
Hidemasa Yasuda, Soshi Kawai
Summary: In aircraft aerodynamic design, it is important to estimate aircraft aerodynamic characteristics using computational fluid dynamics. Wall-modeled large-eddy simulation is proposed to improve the accuracy of simulating unsteady flows. This study introduces three quantitative requirements for matching points to ensure the accuracy of the simulation.
Article
Engineering, Aerospace
M. Angelino, P. Fernandez-Yanez, H. Xia, G. J. Page
Summary: This study introduces a new approach to predict the aerodynamics of aircraft high-lift devices at near-stall conditions, avoiding the computational requirements and reliability issues associated with traditional methods.
Article
Mechanics
Hai-Ning Wang, Wei-Xi Huang, Chun-Xiao Xu
Summary: The study aims to supplement near-wall small-scale turbulence fluctuations with synthetic flow fields generated from a universal model, thereby reducing computational cost. The generated flow is statistically consistent with and structurally similar to authentic MFU.
Article
Engineering, Aerospace
Young Mo Lee, Jae Hwa Lee, Jungil Lee
Summary: Wall-models are crucial in large-eddy simulations (LES) to reduce the computational requirements for resolving near-wall regions in high-Reynolds-number turbulent flows. The proposed artificial neural network-based wall-stress models (AWMs) overcome limitations of the traditional equilibrium models, and demonstrate accurate predictions of wall-shear stress in complex flows. Comparative studies show that AWMs outperform previous wall-models in terms of turbulence statistics for both fully developed turbulent channel flow and separated turbulent boundary layer flow even at untrained Reynolds numbers. Additionally, the issue of log-law mismatch in wall-modeled LESs (WMLESs) with AWMs can be resolved by implementing a dynamically determined filtered wall-normal velocity at the wall based on continuity equation and Taylor series expansion in wall-adjacent cells.
AEROSPACE SCIENCE AND TECHNOLOGY
(2023)
Article
Engineering, Aerospace
Adrian Lozano-Duran, Sanjeeb T. Bose, Parviz Moin
Summary: The study reveals that the accuracy of wall-modeled large-eddy simulation in aircraft aerodynamics depends on grid strategies. Even when the boundary layers are marginally resolved, the prediction error of mean pressure coefficient remains small. However, the accuracy of WMLES predictions of mean velocity profiles decreases at wing-body junctions and separated regions.
Article
Thermodynamics
David M. Peterson
Summary: Simulations were conducted for a round supersonic combustor using a wall-modeled large eddy simulation approach to model turbulence. Combustion was modeled using a small quasi-global mechanism and a more detailed skeletal mechanism. Sensitivity to grid resolution was investigated and a function for the model constant in the partially-stirred reactor model was found. Different combinations of mechanisms and turbulent combustion models can predict the location of the pre-combustion shock train and peak mean pressure, but there are significant differences in temperature and heat release rate fields.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Mechanics
Fengshun Zhang, Zhideng Zhou, Huan Zhang, Xiaolei Yang
Summary: A new single formula, called the LOG-EXP formula, is proposed for predicting the mean velocity profile in different regions near the wall. The formula is tested and shows good performance in various cases, but no significant improvement in Reynolds stresses is observed when refining the grid.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2022)
Article
Mechanics
Ting Jin, Zhizong Chen, Ping Wang
Summary: Wall models have less influence on particle velocities for the same subgrid stress model, but strongly affect the particle volume fraction and mass flux. The combination of dynamic Smagorinsky model and integral model performs the best in this case. The influence of particles on LES models needs urgent research.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2023)
Article
Computer Science, Interdisciplinary Applications
Eron T. V. Dauricio, Joao Luiz F. Azevedo
Summary: Wall-Modeled Large Eddy Simulation (WMLES) is an important technique for obtaining high-fidelity solutions of turbulent, high Reynolds number flows with acceptable computational costs. However, the thin laminar boundary layer near the body leading edge poses restrictive mesh resolution requirements for external flows, resulting in high costs. To address this issue, we propose a wall-modeling approach based on local self-similar solutions of the boundary layer in the context of the WMLES approach. The proposed wall model demonstrates good agreement with the reference solution and is suitable for external laminar flows.
JOURNAL OF COMPUTATIONAL PHYSICS
(2023)
Article
Physics, Multidisciplinary
Yongxiang Li, Florian Ries, Kaushal Nishad, Amsini Sadiki
Summary: This paper examines conjugate heat transfer processes in turbulent channel flow using advanced wall-modeled LES techniques. The study shows that IDDES, WFLES, and zonal LES can accurately predict heat and fluid flow statistics with lower computational costs compared to wall-resolved LES.
Article
Engineering, Aerospace
Imran Hayat, George Ilhwan Park
Summary: This research conducts wall-modeled large-eddy simulations to evaluate the predictive performance of three wall models in turbulent boundary layers subjected to spatially varying streamwise pressure gradients. It is found that all the wall models overpredict the skin friction in the region with a favorable pressure gradient. The overprediction in equilibrium and integral models is attributed to the deviation of mean velocity profiles from the log law, while for the PDE model, it is more pronounced due to a lack of correction for pressure gradients. Potential solutions to mitigate the problem are proposed.
Article
Engineering, Civil
Yong Wang, Xinzhong Chen
Summary: This study validates the accuracy of large-eddy simulation of wind pressures and loads on high-rise buildings at various angles of attack, and proposes local octree mesh refinement as an efficient strategy to improve simulation accuracy.
JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS
(2022)
Article
Mechanics
Zhi-teng Zhou, Zhao-yue Xu, Shi-zhao Wang, Guo-wei He
Summary: This study investigates the directivity of noise generated by turbulent flows around an underwater vehicle, revealing that the interferences of lift and side-force dipoles lead to deviations in the directivities of instantaneous sound pressures from the lift directions.
JOURNAL OF HYDRODYNAMICS
(2022)
Article
Mechanics
Wei-wen Zhao, Fu-chang Zhou, Guo-qing Fan, De-cheng Wan
Summary: This paper numerically simulates turbulent channel flow at Re-& tau; = 1000 using the wall-modeled large-eddy simulation (WMLES) method in conjunction with four different subgrid-scale (SGS) models. The effects of SGS models on predicting turbulent channel flow with WMLES are evaluated by comparing mean velocity profiles, velocity fluctuations, and energy spectra.
JOURNAL OF HYDRODYNAMICS
(2023)
Article
Engineering, Aerospace
Minjeong Cho, Adrian Lozano-Duran, Parviz Moin, George Ilhwan Park
Summary: The study shows that wall-modeled large-eddy simulation (WMLES) performs well in predicting turbulent boundary layers with three-dimensionality, accurately forecasting mean-velocity profiles and separation locations. However, in regions with significant three-dimensional effects, such as bends, prediction errors may increase.
Article
Computer Science, Interdisciplinary Applications
Wai Hong Ronald Chan, Michael S. Dodd, Perry L. Johnson, Parviz Moin
Summary: Knowledge of bubble and drop size distributions in two-phase flows is crucial for understanding phenomena such as combustor ignition, sonar communication, and cloud formation. Accurate identification and tracking algorithms for the dispersed phase are necessary to measure the evolution and quantify the underlying mechanisms in interface-resolving flow simulations.
JOURNAL OF COMPUTATIONAL PHYSICS
(2021)
Article
Computer Science, Interdisciplinary Applications
Yu Lv, Xiang I. A. Yang, George Park, Matthias Ihme
Summary: An augmented discontinuous Galerkin method is developed for wall-modeled large-eddy simulations, which improves solution accuracy on significantly underresolved grids and reduces spurious oscillations. The proposed method reproduces log-law profile for different flow conditions and demonstrates capability for computations of complex flows, such as shock-induced boundary-layer separation.
COMPUTERS & FLUIDS
(2021)
Article
Mechanics
Lin Fu, Sanjeeb Bose, Parviz Moin
Summary: Accurate prediction of aerothermal surface loading is essential for high-speed flight vehicle design. Numerical solution of hypersonic flow over a double-finned geometry with 3D shock-wave/turbulent boundary layer interaction at Mach 8.3 using wall-modeled large eddy simulation (WMLES) shows good agreement with experimental measurements and improves accuracy compared to prior RANS calculations.
THEORETICAL AND COMPUTATIONAL FLUID DYNAMICS
(2022)
Article
Engineering, Aerospace
Adrian Lozano-Duran, Sanjeeb T. Bose, Parviz Moin
Summary: The study reveals that the accuracy of wall-modeled large-eddy simulation in aircraft aerodynamics depends on grid strategies. Even when the boundary layers are marginally resolved, the prediction error of mean pressure coefficient remains small. However, the accuracy of WMLES predictions of mean velocity profiles decreases at wing-body junctions and separated regions.
Article
Physics, Fluids & Plasmas
Rahul Agrawal, Michael P. Whitmore, Kevin P. Griffin, Sanjeeb T. Bose, Parviz Moin
Summary: A major drawback of Boussinesq-type subgrid-scale stress models in large-eddy simulations is the assumption of alignment between large-scale strain rates and filtered subgrid-stresses. A new non-Boussinesq subgrid-scale model with dynamically computed coefficients has been proposed to address this issue and provide sufficient dissipation of turbulent kinetic energy.
PHYSICAL REVIEW FLUIDS
(2022)
Article
Computer Science, Interdisciplinary Applications
Suhas S. Jain, Parviz Moin
Summary: This study utilizes the conservative diffuse-interface method to simulate compressible two-phase flows and proposes discrete consistency conditions for numerical fluxes to ensure conservation of kinetic energy and entropy. The stability of the proposed method is verified in canonical test cases, as well as in flows with droplets.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Editorial Material
Mechanics
Howard A. Stone, Parviz Moin
ANNUAL REVIEW OF FLUID MECHANICS
(2023)
Article
Computer Science, Interdisciplinary Applications
Suhas S. Jain, Michael C. Adler, Jacob R. West, Ali Mani, Parviz Moin, Sanjiva K. Lele
Summary: This work describes three diffuse-interface methods for simulating immiscible, compressible multiphase fluid flows and elastic-plastic deformation in solids. The methods include localized artificial diffusivity, gradient-form, and divergence-form approaches. The primary objective is to compare these methods in terms of their ability to maintain interface thickness, conserve mass, momentum, and energy, and accurately represent interface shape over time. The work also extends these methods to model interfaces between solid materials with strength.
JOURNAL OF COMPUTATIONAL PHYSICS
(2023)
Article
Physics, Fluids & Plasmas
Hanul Hwang, Dokyun Kim, Parviz Moin
Summary: This paper is associated with a winner video of the 2021 American Physical Society's Division of Fluid Dynamics (DFD) Gallery of Fluid Motion Award. The original video can be viewed online at the Gallery of Fluid Motion website.
PHYSICAL REVIEW FLUIDS
(2022)
Article
Mechanics
Xiaohan Hu, Imran Hayat, George Ilhwan Park
Summary: This study investigates the predictive capability of three widely used wall models for three-dimensional turbulent boundary layer using wall-modelled large-eddy simulation (WMLES). The results show that while the wall-stress magnitudes predicted by the three wall models are comparable, the PDE non-equilibrium wall model produces a substantially more accurate prediction of the wall-stress direction. The triangular plot of the wall-model solution reveals different capabilities of the wall models in representing variation of flow direction along the wall-normal direction. However, the type of wall model used does not significantly affect the outer LES solution, resulting in nearly identical predictions of mean and turbulent statistics in the outer region.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Computer Science, Interdisciplinary Applications
Imran Hayat, George Ilhwan Park
Summary: This paper discusses the efficient implementation of wall models in parallel unstructured-grid solvers, focusing on physical and numerical improvements to two zonal wall models based on integral form of the boundary layer differential equations. The first model introduces a novel implementation of the ODE equilibrium wall model, while the second model proposes a modified form of the integral wall model. The authors also identify and propose solutions to numerical challenges unique to the implementation of these integral models in unstructured mesh environments. The computational performance of the wall models is assessed, showing comparable computational cost for the integral wall model and superior cost scaling for the spectral implementation.
JOURNAL OF COMPUTATIONAL PHYSICS
(2023)
Article
Engineering, Aerospace
Imran Hayat, George Ilhwan Park
Summary: This research conducts wall-modeled large-eddy simulations to evaluate the predictive performance of three wall models in turbulent boundary layers subjected to spatially varying streamwise pressure gradients. It is found that all the wall models overpredict the skin friction in the region with a favorable pressure gradient. The overprediction in equilibrium and integral models is attributed to the deviation of mean velocity profiles from the log law, while for the PDE model, it is more pronounced due to a lack of correction for pressure gradients. Potential solutions to mitigate the problem are proposed.
Article
Mechanics
Konrad A. Goc, Oriol Lehmkuhl, George Ilhwan Park, Sanjeeb T. Bose, Parviz Moin
Summary: This paper systematically studies the predictive capability of LES for a range of angles of attack, grid resolution, and wind tunnel effects. The results show reduced grid point requirements while maintaining accuracy, demonstrating potential for industrial use in aeronautical design.