The point power spectrum density and the wavenumber frequency spectrum density of turbulent - boundary- layer fluctuation pressure were measured in water-tunnel by use of a 8 mm hydrophone and a 20-element array, resp...The point power spectrum density and the wavenumber frequency spectrum density of turbulent - boundary- layer fluctuation pressure were measured in water-tunnel by use of a 8 mm hydrophone and a 20-element array, respectively. The non-dimensional representation of measured point power spectrum coincides with the measured results by Bull M. K. et. al. in wind tunnel. The convection peak can be seen clearly in the measured wavenumber frequency spectrum and the convection velocity can be calculated from the location of the convection peak. The response spectrum of a polyvinylidence fluoride (PVDF) hydrophone, which receiving area is 100 mm× 60 nun, was also measured. By comparing it with the response spectrtum of the 8 mm hydrophone, it is shown that the PVDF hyrdophone has a strong wavenumber filtering effect on turbulent - boundary-layer pressure fluctuation.展开更多
文摘The point power spectrum density and the wavenumber frequency spectrum density of turbulent - boundary- layer fluctuation pressure were measured in water-tunnel by use of a 8 mm hydrophone and a 20-element array, respectively. The non-dimensional representation of measured point power spectrum coincides with the measured results by Bull M. K. et. al. in wind tunnel. The convection peak can be seen clearly in the measured wavenumber frequency spectrum and the convection velocity can be calculated from the location of the convection peak. The response spectrum of a polyvinylidence fluoride (PVDF) hydrophone, which receiving area is 100 mm× 60 nun, was also measured. By comparing it with the response spectrtum of the 8 mm hydrophone, it is shown that the PVDF hyrdophone has a strong wavenumber filtering effect on turbulent - boundary-layer pressure fluctuation.
