We describe a problem that the multifluid dynamic equations are not closed.To solve equations,they must be closed.Existing closing relations are analyzed and an adaptive closing relation method according to sound velocity is given.Numerical example shows that pressure relaxation is also important for pressure equalization in mixed cells.

Material properties are investigated on ballistic performance of tungsten-alloy rods with two-dimensional numerical simulations by program LS-DYNA.In an elastic-plastic hydrodynamic material model,primary parameters of the rod includes failure strain,yield stress and shear modulus,etc.Penetration is studied through simulation of a tungsten-alloy rod impacting on a semi-infinite aluminum-alloy target.It is shown that failure strain shows dominant effect on penetration. Numerical simulations of penetration within impact velocity regime ranging from 785 m/s to 1 924 m/s are performed.Numerical results are in good agreement with experimental data.