Comparison of different methods of numerical simulation of flow and sound fields around a square cylinder at various incidence angles

In current study turbulent flow around a 3D square cylinder is modeled using large eddy simulation and shear stress k-ω turbulence modeling for three values of Reynolds numbers 5000, 46000 and 69000. The flow and sound field simulations are conducted by using fluent commercial software. Sound pressure level in the acoustical far field and on the surface of the square cylinder at incidence are evaluated for six angles of attack. Flow induced sound at far field is predicted by employing FWH analogy while sound pressure level over the surface model is directly estimated by measuring the unsteady surface pressures. The results of the present study showed good agreement with the available experimental results. The fluctuating lift and drag forces acting on the square rod and flow turbulence are the main sources of the acoustic field generation. It is noticed that the minimum of drag coefficient, mean and root mean squared (rms) value of lift coefficient, and sound pressure level in acoustical far field occurred at 13 angle of attack. The maximum Strouhal number occurred at 13o angle of attack. The Strouhal number for all angles of attack is noticed to be independent of the flow Reynolds number. Both turbulence models considered in this study predict the acoustic and flow features within an acceptable accuracy.