Statistical estimation of turbulent trailing edge noise

Abstract

The efficient computation of turbulent airfoil trailing edge noise is important for the cost-effective design of fixed and rotary-wing aircraft, wind turbines, fans and submarines. Recently, the computation of trailing edge noise has mainly been attempted using either direct or hybrid methods of computational aeroacoustics (CAA). However, many of these approaches rely on expensive transient flow solution methods for acoustic source term calculation, such as direct numerical simulation (DNS) or large eddy simulation (LES), which aren't appropriate for engineering design purposes. This paper will present a new approach for calculating turbulent trailing edge noise. Instead of using DNS or LES for a flow solution, the method uses mean flow solutions (Reynolds Averaged Navier Stokes or RANS) and a statistical model to calculate acoustic source terms and radiated far-field noise. After the method is presented, results showing the noise generated by the passage of turbulent flow past a sharp edged flat plate will be shown. For the purposes of validation, the model will use mean flow data from both DNS and RANS solutions to calculate the acoustic source terms. Simulated noise will then be compared with an empirical model of flat-plate trailing edge noise. The paper will conclude with remarks on the accuracy of the method and a discussion of future test cases required to test its validity in more challenging flow conditions.