One of key issues in high energy density physics is clarification of transport and energy deposition of laser-produced fast electrons traveled through dense plasma. However, modeling these systems numerically is still a great challenge. In this paper, we introduce a PIC/fluid hybrid model. In this hybrid method, fast electrons are modeled by a relativistic Fokker-Planck equation, which numerically solved by reducing it to equivalent stochastic differential equations. Background electrons and ions are treated as two-fluid model. Collisions, electric and magnetic fields, and evolutions of resistivity due to heating of background are included. Treatment is valid for fast electron number densities much less than that of background, fast electron energies much greater than background temperature, and time scales short enough that magnetic diffusion and thermal conduction can be negligible. Model of ionization and resistivity also determine validity of the model.

From mass conservation and energy conservation of hotspot, dynamics of hotspot combustion involving shell-mix are constructed by recalculating special internal energy and heat capacity, in which bremsstrahlung radiation loss and other energy transfer are considered. With power balance in hotspot, relations between fractions of shell-mixing in hotspot and ignition threshold and self-sustainable combustion are investigated. Theoretical analysis and numerical simulation show that enhancement of radiation loss induced by shell-mixing plays dominated role in failure of ignition. By adjusting materials and mixing fraction, effects to combustion paths are studied. Finally, two methods for degrading impact of shell-mixing are proposed.

To investigate injury of windblast at high speed,flow around a seat occupant is simulated in a scale adaptive simulation turbulence model. Numerical simulations agree well with wind tunnel experiments at Mach number 0.6 and angles of attack from -90° to 90°. Flow around seat occupant without protection is simulated. Injury of pilot during high speed ejection is investigated. It shows that high pressure zones load on pilot are face,thorax,abdomen,inside of upper arm and windward side of calves. As pitch angle increases pressure distribution on each part can improve.

A corrected panel method is shown and applied to static aeroealsticity.Based on CFD data at different attack angles the method approximates curved lifting lines by linear segment.The corrected panel method fills drawback of original one by considering nonlinear factor.Compared with CFD,similar accuracy limit and higher efficiency are obtained in aerodynamic force loss and attack angle compensation of M6 wing.It indicates that the method is suitable for complex structure optimization.

A reduced chemical kinetics model for typical combustion reaction systems is derived by means of the Computational Singular Perturbation (CSP) method.The combustion reaction governing equations are employed to construct ideal basis vectors,with them the coupling between the fast mode and the slow mode is decoupled properly.Several significant parameters are defined,such as the participation index,the radical pointer,and the importance index.Then the state equations of the fast modes and the reduced chemical kinetics model are obtained.A typical mixed combustion reaction system of CO-CH₄-Air is calculated,and the results show that the reduced combustion reaction system obtained by CSP method approximates the original system well.

Unbalanced Stiff equations are used to simulate the nonequilibrium phenomena of radiation.The parallelism of the numerical computation is analyzed and a kind of load balancing method is given.In order to increase the data locality, a sequencing computation method in multi-processors is also given.With the corresponding parallel algorithm of the simulation,the results testified on the workstations are provided and discussed.

The finite-difference time-domain (FDTD) algorithm is employed to simulate microwave pulse coupling into narrow slots which have depths much narrower than on FDTD cell.It analyzes the parallelism of FDTD algorithm and presents a parallel algorithm of simulation.In order to reduce the communication time, it also uses the message fusion and the lap of computation and communication.In addition it analyzs the complex of the parallel algorithm and gives some results on the Alpha workstation.

A parallel algorithm (PAA algorithm) is presented for the solution of diagonally dominant periodic tridiagonal linear systems. Its computation complexity is O(8n) and its communication complexity is O(1). But now the computation and communication complexity of the best parallel algorithm are O(17n) and O (log P) respectively. The PAA algorithm is implemented on the SGI Indy workstation cluster. The results show that the speed up has been improved linearly and the paralleling efficiency reaches to 90%.

Ionization rate of Hydrogen atom in a two-color laser field is calculated by using the method developed by Kulander etc.Change of ionization rate-phase relation is found when the field intensity goes up to threshold and comparison with classical calculation has been done.