An evaporation model at steady state was bulit to analyse effect of solar radiation on evaporation of still water surface at low airflow velocity. It considers convective heat and mass transfer from water surface to airflow,interior heat transfer and solar radiation absorbing spectrum of water. Finite volume method combined with Monte Carlo method and spectral band model are used to simulate energy and mass transfer among water interior,surface and airflow. Effect of solar irradiance on evaporation rate of water surface was analysed at different airflow velocity,humidity,temperature,forward and inverse temperature difference. It shows that solar irradiance effect on evaporation of still water surface is great at low airflow velocity.

Lattice Boltzmann method(LBM) and back and forth error compensation and correction(BFECC) skill are combined together for two-dimensional incompressible flows with quad-tree mesh.The scheme is equivalent to conventional LBM. Results for flows in two-dimensional cavity and around a cylinder demonstrate the scheme.

A numerical study on shearing movement of granular system with a dragging solid body on top is presented.It focuses on friction between body and particles.It shows that friction coefficient varies with dragging velocity.This behavior,totally different from interaction between two solid bodies,implies complexity of granular system.

The size segregation of grains is studied with two-dimensional molecular dynamic simulations for dissipative particles under horizontal vibration.A series of segregation that induced by horizontal vibrations at different amplitudes and frequencies are reported and the relationship between these two aspects is analyzed.A standard is given to scale the speed of the segregation.It is found that an optimal amplitude exists at a given frequency.An empiristic formula is obtained for this amplitude.It shows that another segregation mechanism exists at a large amplitude and frequency,in which the big particles are thrown directly to the top by the side wall.

The strict explanation about conservation on discrect sitiuation is given at first.Then the dilemma among different conservative variables are discussed,and a least squart method is presented to solve it.Some easily confused concepts about conservation are analysed in detail.

Based on the modification to the integal domain, an upwind finite element scheme is presented. Just as the first order upwind difference scheme, which is its conterpart in finite difference methods, it applies to construct many numerical schemes on unstructed grids.

FEM-FCT is used to solve three-dimensional hypersonic inviscid flow.The flow fields around sphere,modified space shuttle orbiter and capsule type vehicle are gained on unstructured tetrahedron grids.The results show that the scheme is valid and has high resolution to shock waves.

By defining vaccum self-energy diagrams and using REDUCE programming langauge, the calculation of renormalization constans in the weinberg-salam standard model can be performed by computer.