Numerical prediction of turbulent boundary layer noise from a sharp‐edged flat plate. (24th April 2019) - Karimi, Mahmoud
Summary: An efficient hybrid uncorrelated wall plane waves–boundary element method (UWPW‐BEM) technique is proposed to predict the flow‐induced noise from a structure in low Mach number turbulent flow. Reynolds‐averaged Navier‐Stokes equations are used to estimate the turbulent boundary layer parameters such as convective velocity, boundary layer thickness, and wall shear stress over the surface of the structure. The spectrum of the wall pressure fluctuations is evaluated from the turbulent boundary layer parameters and by using semi‐empirical models from literature. The wall pressure field underneath the turbulent boundary layer is synthesized by realizations of uncorrelated wall plane waves (UWPW). An acoustic BEM solver is then employed to compute the acoustic pressure scattered by the structure from the synthesized wall pressure field. Finally, the acoustic response of the structure in turbulent flow is obtained as an ensemble average of the acoustic pressures due to all realizations of uncorrelated plane waves. To demonstrate the hybrid UWPW‐BEM approach, the self‐noise generated by a flat plate in turbulent flow with Reynolds number based on chord R e c = 4.9 × 10 5 is predicted. The results are compared with those obtained from a large eddy simulation (LES)‐BEM technique as well as with experimental data from literature. Abstract : An efficient approach that combines RANS, the boundary element method and an uncorrelated wall plane wave technique is proposed for prediction of flow-induced noise from a sharp-edged plate in low Mach number turbulent flow. The wall pressure field in a turbulent boundary layer is formulated as a deterministic load for the acoustics solver based on the BEM. Results from the proposed technique are verified and validated with results from an LES‐BEM solver as well as experimental data.