Hybrid Computation of the Aerodynamic Noise Radiated by the Wake of a Subsonic Cylinder

Abstract

The noise radiated by the flow around a cylinder in the subcritical regime at ReD=1×104 and at a subsonic Mach number of M=0.5 is here studied. The aerodynamic sound radiated by a cylinder has been studied with a wide range of Reynolds numbers, but there are no studies about how the Mach number affects the acoustic field in the subsonic regime. The flow field is resolved by means of large-eddy simulations of the compressible Navier–Stokes equations. For the study of the noise propagation, formulation 1C of the Ffowcs Williams–Hawkings analogy is used. The fluid flow results show good agreement when comparing the surface pressure coefficient, the recirculation length, the vortex shedding frequency and the force coefficients against other studies performed under similar conditions. The dynamic mode decomposition of the pressure fluctuations is used to relate them with the far-field noise. It is shown that, in contrast to what happens for low Mach numbers, quadrupoles have a significant impact mainly in the observers located in the streamwise direction. This effect leads to a global monopole directivity pattern as the shear fluctuations compensate for the lower value of the aeolian tone away from the cross-stream direction.

Toward the Usage of Deep Learning Surrogate Models in Ground Vehicle Aerodynamics

“…In this study, the DMD computations have been conducted using pyLOM [64], which is a high-performance computing tool for modal decompositions already used by Miró et al [65] and Eiximeno et al [66] for DMD analysis. In pyLOM, the computation of A follows the algorithm proposed by Tu et al [67].…”