WAKE FLOW - ACOUSTIC RESONANCE IN A GENERIC AIR OUTLET

We aim to investigate the noise generation mechanism in a generic geometry representing a typical air outlet of an HVAC system of a car. We use an Aero-Acoustic simulation based on Large-Eddy Simulation and an experiment to study the interaction between a throttle plate (used to control the flow rate) and fins (used to guide the flow). We can identify several sound generation mechanisms, of which the so-called Parker β-mode is the most prominent in the sensible frequency range. Our focus is on the interaction and resonance of this acoustic mode with the vortex shedding modes in the wake of the throttle valve, which seems to play a major role in determining the amplitude of the acoustic mode.