基于时间分辨PIV的柱状翼型噪声的气动声学研究

The rod-airfoil con痝uration is a benchmark test case for aeroacoustic assessments of vortex- structure interaction noise. Several industrial devices are arranged in such a way that down- stream bodies are embedded in the wake of upstream bodies, such as gas turbines, high lift devices, helicopters among others. Aeroacoustic predictions usually rely on time dependent 皁w 痚ld information obtained from CFD for the determination of the aeroacoustic sources. The present work proposes a novel approach for the aeroacoustic prediction of rod-airfoil noise based on time-resolved PIV experimental data. The aeroacoustic emission of a NACA0012 airfoil in the Karman wake of a rod is investigated by means of 2D TR-PIV in combination with beamforming and microphone measurements. First the time evolving velocity 痚ld around the airfoil is measured using high-speed PIV. The corresponding pressure 痚ld is then deduced by spatial integration of a Poisson-based algorithm for quasi-2D incompressible 皁ws. Pressure and velocity computed on speci痗 surfaces around the airfoil constitute the source terms of the implemented Curle's and Ffowcs Williams-Hawkings's aeroacoustic analogies. The calculated Sound Pressure Level (SPL) is compared with the measurements obtained by far 痚ld microphones. Velocity visualizations in the spanwise direction provide qualitative information about the phase coherence of the vortical impingement along the airfoil span. Parametric studies are performed to evaluate the e甧ct on the acoustic prediction of the position of the integration surface and the numerical discretization methods employed.