AEROACOUSTIC SOUND PREDICTION OF A DIAPHRAGM BY A HYBRID METHOD

Most of the noise prediction methods, which have been previously used, only applicable at low frequencies range, below the first transverse duct mode. A developed method at this work, which was suggested by Schram, avoided many simplifying assumptions and it is quite powerful for high Helmholtz numbers, i.e. when the turbulence/body interaction region is acoustically non-compact. By using numerical methods and an appropriate Green function, the method is applied to the prediction of sound in a duct obstructed by a diaphragm. The source fluctuations of the flow field are computed by large-eddy simulation (LES) and they are fed to the following acoustical computation as input data.The predicted power spectrum shows a fairly good agreement with a direct noise computation (DNC) results.

کلیدواژه ها:

Aeroacoustic ، Diaphragm ، Helmholtz number