As an important multi-scale coupling method, lattice Green function (LGF) bridges gap between density functional theory (DFT) calculations on atomic scale and large-scale continuum medium elasticity theory, especially for material containing dislocation-doping complex. With LGF equilibrium dislocation core structure can be obtained. It provides basis for DFT calculations of interaction between dislocation and doping atoms. Based on lattice dynamics and force-constant matrix, LGF of perfect nickle lattice is obtained with special k-points sampling and Fourier transform, which can be applied in multi-scales calculation of nickle-base superalloy.

Acoustic streaming generated by standing waves between two-dimensional flat plates is analyzed based on multiple relaxation time lattice Boltzmann method (MRT-LBM). Simulation results are in good agreement with approximate analytical solutions of Rayleigh streaming. Effects of viscosity and width between two plates on acoustic streaming in standing waves are studied. Dimensionless velocity distributions of x component with different viscosity at x=L/4 and dimensionless velocity distributions of y component with different viscosity at x=L/2,and effects of widths on boundary layer vortex thickness and formation progress of acoustic streaming in standing waves are revealed. It demonstrates availability of MRT-LBM model in simulating acoustic streaming in standing waves.

An explicit equation for critical quantity of heat in condensing flow in a shock tube was derived.The equation is of general validity and applies tO vapor flow with or without cagier gas.It shows that critical quantity of heat in internal heat flow for phase change is greater than external heat flow.As flow is choked thermally,a shock wave is generated and propagates upstream.A location where local static pressure begins to rises,which has long been regarded as onset of unsteady condensation in a steady supersonic nozzle,is not acceptable in shock tube flow.It is before the zone of condensation.Furthermore,a second-order AUSM scheme is applied tO two-dimensional compressible flow with condensation.Computation results reproduce integral predictions well.

A compressible large eddy simulation (LES) technique based on a highly efficient and well validated finite volume,multigrid driven method is developed.The Jameson's central scheme with second and fourth order artificial dissipation is used for space discretization and dual time methodology is implemented for time marching.The subgrid scale stress tensor and the subgrid scale heat flux are simulated with Smagorinsky model.A typical simulation of isotropic turbulence decay is performed to verify the accuracy and efficiency of this method.The simulated time evolution of energy spectra and decay of the resolved turbulence kinetic energy are in good agreement with the filtered experimental CBC data.

The one-dimensional ideal elastic-plastic fluid hydrodynamical model with finite difference method is used to study the processes of formation and decay of the shock waves induced by laser irradiation to solid targets and effects of dynamic fracture.

By means of a hydrodynamic model in which electrons and ions have different temperature and same isothermal expanding velocity,it deals with interaction process of the intense pulse laser with the target,and gives scaling relationships between the plasma parameters and the laser or the target behaviour,in which include equilibrium absorption and radiation in the plasma.

A numerical method and an analytical method for study creation and decay of laser generated shock-wave in the target are presented on the basis of one-dimensional hydrodynamic model.The ablation presure is used as boundary condition.These methods permit the caculation of the three stages of shock-wave evolution.Three kinds of solid state material,such as Al,Cu and C/Ph are caculated.The maximum presure and shock-wave profile of each material are given out.