Numerical simulation and analysis of fluctuating pressure on outside surface around model was conducted using large eddy simulation of soft ware Fluent. It is obtained that the scattergram of fluctuating pressure on outside surface of high-speed automobile. The result shows that the scattergram of fluctuating pressure by large eddy simulation coincides with the test results. It can be concluded that the calculations are available for project but the precision of simulation need be improved.

The finite element method is used to analyze the acoustic characteristics of an expansionchamber muffler with its inlet and outlet pipes being coaxial. Its transmission loss (TL) is calculated. The result is compared with that of the onedimensional solutions based on planar wave theory. The limitation of onedimensional planar wave theory is discussed. The acoustic characteristics of eccentric outlet muffler, doubleoutlet muffler and doublecavity muffler are analyzed. The result indicates that the position and the number of outlet can affect the acoustic characteristic of a muffler for higher and medium frequencies; while the doublecavity muffler has high noiseelimination efficiency for lower and medium frequencies.