文档介绍：CFD modeling of dense gas cloud
dispersion over irregular terrain
Robert N. Meroney a,
aWind Engineering Software, Fort Collins, CO,USA, Robert.******@
1 INTRODUCTION
Computational techniques for dense gas cloud dispersion generally fall into four categories
depending on the simplicity of the models—box models (volume integrated), slab models
(cross-section integrated) shallow layer (depth integrated), and full 3-d field models (K or
advanced turbulence models) (Duijm et al., 1997).
Box and slab models require the stipulation of boundary entrainment rates which are
normally prescribed in terms of local relative cloud velocities (U and Re) frontal velocities
(u g ), boundary friction (u *) stratification (Ri *, Gr) and for cold gases the temperature po-
*
tential (T ) or convective velocity (w *) such that the entrainment velocity, w e = f(u g, u *,
w*, Ri *, Re . (Meroney, 1983, 1984a, 1984b, 1985) Empirical coefficients in these solu-
tion procedures are assigned based parison with field or model experiments; hence,
the results are often dependent on the data set used to calibrate the calculation scheme.
Volume integration of the equations of motion, energy and mass species result in sets
of ordinary differential equations in time which may be solved by standard Runga-Kutta
solution procedures; hence, they are extremely fa