Whistling of restriction orifices:aeroacoustic source identification

The study presents a simple source identification method applied to restriction orifices. A restriction orice in a duct can whistle when it is submitted to a low Mach number flow. The orice acts as an amplifier for the incident acoustic energy. The method, earlier presented by Martinez-Lera et al1 and improved by Nakiboglu et al,2 combines incompressible numerical simulations with vortex sound theory. The application of the method to the source identification of whistling restriction orifices predicts whistling at Strouhal numbers similar to earlier experimental and numerical studies, with limited computational effort.