Influence of wall surface on growth of frost layer is studied by using mesoscale lattice Boltzmann method. Nucleation probability model is coupled with improved enthalpy model. A lattice Boltzmann model of frost layer growth process based on nucleation probability theory is established. It simulates thickening of frost layer growth on macro scale, and dynamic change of frost layer structure caused by growth of ice branches in microscale as well. Average thickness, average density and frosting amount of frost layer are obtained. Formation and growth of frost layer on cold wall surface are studied. Temporal and spatial evolution of topological structure of frost layer are obtained. Average thickness, average density and average solid volume fraction of frost at different time were calculated and effects of cold wall surface temperature, relative humidity and cold surface infiltration on frost were discussed.

Based on finite element and artificial transmitting boundary method, the cylindrical wave scattering by infinite circular cylinder is computed and compared with analytical solution. Then other problems on scattering induced by irregular objects are also solved on use of the same method, whose superiority and efficiency have been indicated by numerical examples.

The scattering of waves from a cylindrical obstacle burried in the dielectric half-space can be investigated by many means. One of them is discrete method. But it is difficult to deal with the radiation conditions on the artificial boundaries of finite calculating region. To eliminate the effects of waves reflected from the artificial boudaries, an Artificial Transmitting Boundary Method was given by seismology circles and has been applied to some scattering problems successfully/In this paper, as a trial, the method mentioned above is combined with Finite Element Method and applied to give out the near-field solutions. Then, making use of the results, the far-field solutions are given with Green's function method. Finally, the results from the method used here are compared with those from the integral equations method. It is verified that the new method used here is feasible.