Validation setup for the investigation of aeroacoustic and vibroacoustic sound emission of confined turbulent flows

Confined flows induce sound at certain flow conditions, resulting in reduced passenger comfort, especially in electric vehicles due to the absence of combustion noise. Noise in internal flows may arise due to unfavorable flow-guiding geometries caused by the complex packaging required in engine compartments of modern vehicles. The flow-induced sound is emitted at duct openings (e.g., ventilation inside the passenger cabin), but also originates from vibroacoustic emissions of the flow-guiding structure excited by the flow. We propose a modular validation procedure for aeroacoustic simulations of confined flows. The experimental setup includes the vibroacoustic emission of the involved flow-guiding structure. The test rig consists of a high-pressure blower, modular pipe sections, and absorbers decoupling the system from blower noise and avoiding acoustic reflections at the pipe exits. The rig is equipped with a sensor system. A sufficiently long straight inlet section ensures fully developed flow conditions at the entrance into the investigated region. The measurement object and surrounding microphones are encapsulated in a measurement chamber, lined with micro-perforated plates to capture the sound radiation of the flow-guiding structure. Besides the setup description, results of measurements from pipe flow across a half moon-shaped orifice are presented.