Three model problems were examined to assess the diiculties involved in using a hybrid scheme coupling ow computation with the the Ffowcs Williams and Hawkings equation to predict noise generated by v ortices passing over a sharp edge. The results indicate that the Ffowcs Williams and Hawkings equation correctly propagates the acoustic signals when provided with accurate ow information on the i...

An acoustic analysis based on the Ffowcs Williams and Hawkings equation was performed for a high-lift system. As input, the acoustic analysis used unsteady ow data obtained from a highly resolved, time-dependent, Reynolds-averaged Navier-Stokes calculation. The analysis strongly suggests that vor-tex shedding from the trailing edge of the slat results in a high-amplitude, high-frequency acousti...

We present 3-D Large Eddy Simulation (LES) results for a turbulent Mach 0.9 isothermal round jet at a Reynolds number of 100,000 (based on jet nozzle exit conditions and nozzle diameter). Our LES code is part of a Computational Aeroacoustics (CAA) methodology that couples surface integral acoustics techniques such as Kirchhoff’s method and the Ffowcs Williams-Hawkings method with LES for the fa...

A mass-conserved formulation for the Ffowcs-Williams–Hawkings (FW–H) integral is proposed to suppress contributions of spurious mass flux far-field sound at very low Mach numbers. The condition and compact-source region assumptions are employed. By using higher-order derivatives Green’s function, an expansion integrand in monopole term performed. This transforms mass-flux like into a series inc...

No AccessTechnical NotesLighthill Stress Flux Model for Ffowcs Williams–Hawkings Integrals in Frequency DomainZhiteng Zhou, Hongping Wang, Shizhao Wang and Guowei HeZhiteng ZhouState Key Laboratory of Nonlinear Mechanics, Chinese Academy Sciences, 100190 Beijing, People’s Republic China*Ph.D. Candidate, Institute Mechanics; also School Engineering University 100049 China.Search more papers by t...

Abstract A hybrid noise computation method is presented in this paper. Large-eddy simulation with wall-model equation proposed to compute the flow field. With a stress-balanced equation, near-wall cost of large eddy was effectively reduced. The instantaneous variables obtained by large-eddy were used source terms Ffowcs Williams–Hawkings equation. present investigated two test cases: single cyl...

Aeroacoustics, the science of noise generation and propagation through airflows, is a relatively young discipline compared to other more classical fields of mechanics. Nevertheless, it has seen tremendous progress since its foundations were laid in the form of the first overall aeroacoustic theory by Lighthill in his pioneering work in 1952. The basic understanding of aerodynamically generated ...