Toward Hybrid CAA with Ground Effects

Abstract

CAA based on the Linearised Euler Equations (LEE) is applied to propagate aerodynamic sound over an extended distance including ground effects. The LEE are coupled to data from an LES via an acoustic analogy to follow-up the sound from the source to the extended far field: the complete chain is illustrated on the sound generated by a cylinder in a M ∼ 0.2 and Re ∼ 48000 flow. A very good agreement is found in free field between the approach based on the Ffowcs-Williams & Hawkings (FWH) analogy only and the combined FWH-LEE approach. The ability of the combined approach to handle complex boundary conditions is illustrated on the same data set with a rigid and a grassy ground.