Large-eddy simulation of a passive scalar in isotropic turbulence

Abstract

TEMTY, a code for large-eddy simulation of a passive scalar in isotropic turbulence, is developed and proved by successful simulation of experiment. The role of each term in the scalar equation and the concept of prefiltering the scalar equation is examined. The ratio of the exponents in the decay of velocity and temperature intensities is found to parametrize with the ratio Λu/Λ0, where Λu, Λ0, are the velocity and temperature Taylor microscales respectively.

Numerical simulation of dispersion around an isolated cubic building: Model evaluation of RANS and LES

“…Near the wall, the length scale is modified by a van Driest damping function. The subgrid scale Schmidt number was set to 0.5 [25]. A second-order centered difference scheme is adopted for the spatial derivatives.…”

CFD Analysis of Turbulent Flow Past Square Cylinder Using Dynamic Les

“…However, the S model has several shortcomings; e.g., (a) the S model is overly dissipative, (b) the Smagorinsky constant, C 1 , must be optimized for each #ow"eld, etc. The Smagorinsky constant, C 1 , in the S model is optimized from 0)1 to 0)25 for various #ow"elds (Schumann 1975;Clark et al 1979;Monsour et al 1979;Antonopoulos-Domis 1981;Biringen & Moin 1981;Moin & Kim 1982;Horiuti 1987;Mason 1989;Mason & Derbyshire 1990;Mizutani et al 1991). As was already pointed out, the #ow"eld around a blu!…”

Symmetry-Preserving Discretization of Heat Transfer in a Complex Turbulent Flow

“…In matrix-vector form, the conservation-of-mass law (19) may then be written as M u 1 u h = 0. As the mass and the scalar φ are transported at equal velocities, the mass flux is used to discretize the convection of the scalar φ through the boundaries of the grid cell Ω i, j , Figure 3.…”

“…The diagonal elements of the coefficient matrix C 1 (ū) are equal to half the left-hand side of expression (19), hence they are equal to zero if and only if the interpolations of the temperatures to the control faces are performed with constant weights. Then, the coefficient matrix is skew-symmetric,…”

“…As previously, the mass fluxes The leading term in the discretization error may be removed through a Richardson extrapolation (see also [19]). This leads to the fourth-order approximation of the incompressibility constraint,…”