Large eddy simulations of turbulent channel and boundary layer flows at high Reynolds number with mean wall shear stress boundary condition

2013 ◽  
Vol 25 (11) ◽  
pp. 110808 ◽  
Author(s):  
Jungil Lee ◽  
Minjeong Cho ◽  
Haecheon Choi
Keyword(s):  
Boundary Layer ◽  
Boundary Condition ◽  
Reynolds Number ◽  
High Reynolds Number ◽  
Large Eddy Simulations ◽  
Boundary Layer Flows ◽  
Large Eddy ◽  
Stress Boundary Condition ◽  
High Reynolds ◽  
Stress Boundary

scholarly journals Quasi-periodic forces and conditionally averaged characteristics of unsteady cavitation flow around a hydrofoil

2021 ◽  
Vol 2119 (1) ◽  
pp. 012030
Author(s):  
E I Ivashchenko ◽  
M Yu Hrebtov ◽  
R I Mullyadzhanov
Keyword(s):  
Reynolds Number ◽  
Liquid Phase ◽  
High Reynolds Number ◽  
Velocity Fields ◽  
Large Eddy Simulations ◽  
Two Dimensional ◽  
Cavitation Flow ◽  
Large Eddy ◽  
High Reynolds ◽  
Conditional Averaging

Abstract Large-eddy simulations are performed to investigate the cavitating flow around two dimensional hydrofoil section with angle of attack of 9° and high Reynolds number of 1.3×106. We use the Schnerr-Sauer model for accurate phase transitions modelling. Instantaneous velocity fields are compared successfully with PIV data using the methodology of conditional averaging to take into account only the liquid phase characteristics as in PIV. The presence of two frequencies in a spectrum corresponding to the full and partial cavity detachments is analysed.

Subgrid-scale modelling for the large-eddy simulation of high-Reynolds-number boundary layers

1997 ◽  
Vol 336 ◽  
pp. 151-182 ◽  
Author(s):  
BRANKO KOSOVIĆ
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Large Eddy Simulation ◽  
Boundary Layers ◽  
Nonlinear Model ◽  
High Reynolds Number ◽  
Subgrid Scale ◽  
Eddy Simulation ◽  
Large Eddy ◽  
High Reynolds

It has been recognized that the subgrid-scale (SGS) parameterization represents a critical component of a successful large-eddy simulation (LES). Commonly used linear SGS models produce erroneous mean velocity profiles in LES of high-Reynolds-number boundary layer flows. Although recently proposed approaches to solving this problem have resulted in significant improvements, questions about the true nature of the SGS problem in shear-driven high-Reynolds-number flows remain open.We argue that the SGS models must capture inertial transfer effects including backscatter of energy as well as its redistribution among the normal SGS stress components. These effects are the consequence of nonlinear interactions and anisotropy. In our modelling procedure we adopt a phenomenological approach whereby the SGS stresses are related to the resolved velocity gradients. We show that since the SGS stress tensor is not frame indifferent a more general nonlinear model can be applied to the SGS parameterization. We develop a nonlinear SGS model capable of reproducing the effects of SGS anisotropy characteristic for shear-driven boundary layers. The results obtained using the nonlinear model for the LES of a neutral shear-driven atmospheric boundary layer show a significant improvement in prediction of the non-dimensional shear and low-order statistics compared to the linear Smagorinsky-type models. These results also demonstrate a profound effect of the SGS model on the flow structures.

The wall-pressure spectrum of high-Reynolds-number turbulent boundary-layer flows over rough surfaces

2015 ◽  
Vol 768 ◽  
pp. 261-293 ◽  
Author(s):  
Timothy Meyers ◽  
Jonathan B. Forest ◽  
William J. Devenport
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Boundary Layers ◽  
High Reynolds Number ◽  
Wall Pressure ◽  
Boundary Layer Flows ◽  
High Frequency Region ◽  
Pressure Drag ◽  
Roughness Elements ◽  
High Reynolds

Experiments have been performed on a series of high-Reynolds-number flat-plate turbulent boundary layers formed over rough and smooth walls. The boundary layers were fully rough, yet the elements remained a very small fraction $({<}1.4\,\%)$ of the boundary-layer thickness, ensuring conditions free of transitional effects. The wall-pressure spectrum and its scaling were studied in detail. One of the major findings is that the rough-wall turbulent pressure spectrum at vehicle relevant conditions is comprised of three scaling regions. These include a newly discovered high-frequency region where the pressure spectrum has a viscous scaling controlled by the friction velocity, adjusted to exclude the pressure drag on the roughness elements.

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