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In order to study the influence of modal to the noise of the blade, the tests of modal and noise are carried out in the cavitation tunnel. The modal of hydrofoil was measured in the water and the noises of the hydrofoil with different inflow velocity were tested. The results show that the frequency of the peak of the noise spectrum is not changed with the inflow speed increasing. The amplitude of the peak increases first and then decreases with the inflow speed increasing. The structural characteristic of the hydrofoil has important influence on the noise and the frequency of the peak is equal to the modal frequency.

By using the software FIRE, the flow structure of 186FA diesel engine were analyzed by numerical simulation. The indicator diagram, velocity field and turbulent kinetic energy in the cylinder were simulated by both the k-ε model and the large-eddy simulation(LES) model. The results shows that the mesh density has little effect on the flow structure when the k-ε model is adopted. Compared with the k-ε model, the LES model shows a significantly different and relatively more complex turbulence structure，and its turbulent kinetic energy is much lower than that of the latter. At the same time, the finer the mesh is, the more distinct the effect is.