Matching relationship of the wheel/rail profiles is always the main focus of high-speed railway home and abroad, as it has direct influence on the performance, the cost and the safety when railway vehicle running.

Moreover impact models and trajectory models are built up to simulate and analyze accidents, therefore computer - aided accident reconstruction can be realized.

The research aim of this thesis is to establish the whole trajectory model of representing the Moving Objects position, and to solve the tec.

Application of stochastic trajectory model in tail-nozzle SRM flow field numerical simulation;

It is suggested that the part ide- motion- resolution trajectory model is efficient for simulating the dynamic behavior of circulating fluidized beds.

In order to provide analysis results for fault diagnosis in a tailpipe nozzle to make some suggestions,twophase flow field is studied for a tailpipe nozzle by using the trajectory model and finite volume method to obtain the gas temperature and Mach number distributions,and to simulate the collision between the wall and different size particles under different total pressures.