Using Large Eddy Simulations to Predict Fluctuating Wall Pressure Caused by Turbulent Flow over Rough Surfaces

2016 ◽  
Author(s):  
Hua Shan ◽  
. Joseph F. Slomski
Keyword(s):  
Turbulent Flow ◽  
Rough Surfaces ◽  
Wall Pressure ◽  
Large Eddy Simulations ◽  
Large Eddy

scholarly journals Dynamic LES of the magnetohydrodynamic flow in a square duct with the varied wall conductance parameters

2021 ◽  
Vol 2116 (1) ◽  
pp. 012036
Author(s):  
A Blishchik ◽  
S Kenjereš
Keyword(s):  
Electrical Conductivity ◽  
Turbulent Flow ◽  
Magnetohydrodynamic Flow ◽  
Large Eddy Simulations ◽  
Scale Model ◽  
Turbulent Structures ◽  
Square Duct ◽  
Large Eddy ◽  
Side Walls

Abstract The current study is focused on the magnetohydrodynamics and demonstrates how electrical conductivity of the wall can affect the turbulent flow in the square duct. Different variations of the boundary walls have been considered including arbitrary conductive walls. The Large Eddy Simulations method with the dynamic Smagorinsky sub-grid scale model have been used for the turbulent structures resolving. Results show the significant impact of the wall conductance parameters for both Hartmann and side walls.

scholarly journals Large-eddy simulations of turbulent flow for grid-to-rod fretting in nuclear reactors

2013 ◽  
Vol 262 ◽  
pp. 544-561 ◽  
Author(s):  
J. Bakosi ◽  
M.A. Christon ◽  
R.B. Lowrie ◽  
L.A. Pritchett-Sheats ◽  
R.R. Nourgaliev
Keyword(s):  
Turbulent Flow ◽  
Nuclear Reactors ◽  
Large Eddy Simulations ◽  
Large Eddy

Dynamic roughness model for large-eddy simulation of turbulent flow over multiscale, fractal-like rough surfaces

2011 ◽  
Vol 679 ◽  
pp. 288-314 ◽  
Author(s):  
W. ANDERSON ◽  
C. MENEVEAU
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Flow ◽  
Power Law ◽  
Rough Surfaces ◽  
Scale Height ◽  
Small Scale ◽  
Height Distribution ◽  
Subgrid Scale ◽  
Eddy Simulation ◽  
Large Eddy

Many flows especially in geophysics involve turbulent boundary layers forming over rough surfaces with multiscale height distribution. Such surfaces pose special challenges for large-eddy simulation (LES) when the filter scale is such that only part of the roughness elements of the surface can be resolved. Here we consider LES of flows over rough surfaces with power-law height spectra Eh(k) ~ kβs (−3 ≤ βs < −1), as often encountered in natural terrains. The surface is decomposed into resolved and subgrid-scale height contributions. The effects of the unresolved small-scale height fluctuations are modelled using a local equilibrium wall model (log-law or Monin–Obukhov similarity), but the required hydrodynamic roughness length must be specified. It is expressed as the product of the subgrid-scale root-mean-square of the height distribution and an unknown dimensionless quantity, α, the roughness parameter. Instead of specifying this parameter in an ad hoc empirical fashion, a dynamic methodology is proposed based on test-filtering the surface forces and requiring that the total drag force be independent of filter scale or resolution. This dynamic surface roughness (DSR) model is inspired by the Germano identity traditionally used to determine model parameters for closing subgrid-scale stresses in the bulk of a turbulent flow. A series of LES of fully developed flow over rough surfaces are performed, with surfaces built using random-phase Fourier modes with prescribed power-law spectra. Results show that the DSR model yields well-defined, rapidly converging, values of α. Effects of spatial resolution and spectral slopes are investigated. The accuracy of the DSR model is tested by showing that predicted mean velocity profiles are approximately independent of resolution for the dynamically computed values of α, whereas resolution-dependent results are obtained when using other, incorrect, α values. Also, strong dependence of α on βs is found, where α ranges from α ~ 0.1 for βs = −1.2 to α ~ 10−5 for βs = −3.

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