Experimental investigation of surface-pressure fluctuations on a rotating blade

Abstract To compute the broad band noise of an axial fan with simple acoustic models it is necessary to determine the randomly fluctuating forces. These forces can be expressed in terms of distribution of fluctuating pressure on the blade surface and a correlation area. The spectrum of the surface pressure is taken from measurements on rotating fan blades in turbulent flows which are non-dimensionalized by the boundary layer displacement thickness and free stream velocities. The correlation area is nondimensionalized by the squared blade chord. The pressure is measured at various positions at the blade surface for three different operating points and speeds of the fan. The results are compared with those of published literature.