Patent ID: 7555413

Claim:
A method for analyzing fluid by determining a wall-damping function used in subgrid-scale (SGS) modeling for Large Eddy Simulation (LES), comprising: identifying a grid filter width to be used in the modeling; determining an estimated dissipation rate, ε SGS , of SGS turbulence energy, k SGS , where the SGS turbulence energy, k SGS , contains components of wave numbers larger than that of the identified grid filter width, and predicting a dissipation rate, ε, from the dissipation rate, εSGS, of SGS turbulence energy, k SGS , using a length-scale ratio between y and Δ, where y is the distance from a nearest wall surface and Δ is the identified grid filter width; calculating, using a computer, the value of the wall-damping function using the predicted dissipation rate ε; and outputting the wall-damping function value of the turbulent flow to a fluid flow analyzer or displaying the value on a display for use in the modeling; wherein the wall-damping function is f = [ 1 - exp ⁢ { - ( y * A ) B } ] C ⁢ ⁢ where ⁢ ⁢ ⁢ y * = ⁢ u ɛ ⁢ y / v , u ɛ = ( v ⁢ ⁢ ɛ es ) 1 / 4 , ⁢ and ⁢ ⁢ ⁢ ɛ es = ɛ SGS ⁡ ( D ⁢ y Δ ) 2 ⁢ where U ε is a Kolmogorov velocity scale, y is the distance from the nearest wall surface, v is kinematic viscosity, ε es , is the predicted dissipation rate of turbulence energy, Δ is the grid filter width in the LES calculation, A, B, C, and D are model constants, and ε SGS is the dissipation rate of SGS turbulence energy.