An Experimental Investigation of the Influence of an Air Bubble Layer on Radiated Noise and Surface Pressure Fluctuations in a Turbulent Boundary Layer

摘要

An experimental investigation is described which shows relationships between the noise spectra of a layer of air bubbles in a turbulent flow and a maximum stable bubble size which can exist in the same flow. An air bubble layer with individual bubble sizes greater than a maximum stable size was introduced into the boundary layer of water flowing along a smooth flat plate. It was found that the maximum stable bubble size was related to the turbulent kinetic energy dissipation as had been previously shown by other investigators for a variety of turbulent flows. A unique 'corner frequency' of the noise spectra which resulted from the bubble splitting down to a maximum stable size could be also related to the turbulent kinetic energy dissipation of the boundary layer flow. (Author)