Smoothed particle hydrodynamics (SPH) is tested for simulating flow driven by high speed underwater body (FDUB).Developing history of supercavity induced by a body is predicated by SPH.Shape of developed supercavity derived by SPH is compared with result given by principle of independence of cavity sections expansion of Logvinovich.Ghost particle method and Dummy particle method,that remedy boundary deficiency of SPH,are combined to implement wall conditions.

Structures,stabilities,and magnetic properties of Pt_n(n=1-9) are calculated with generalized gradient approximation functional BPW91 and three-parameter hybrid density functional B3LYP in density functional theory.The methods give same stable structures and same lowest-energy structures but different stable order of sub-stable structures.Average coordination numbers and average bond lengths in two methods have similar patterns.They increase with cluster size,and have a great increase at n=2-3 and a small increase at n=4-9.Analysis of energies by two methods show that there are greater values at n=2,5,8,which illustrate that corresponding clusters have high stabilities.Study of Pt clusters indicates that average magnetic moment oscillates with cluster size.It has a gradually decrease trend.It shows that two methods can describe structures,stabilities and magnetism of clusters.