Resolvent-based modeling of turbulent jet noise

Ethan Pickering , Aaron Towne , Peter Jordan (1) , Tim Colonius

1 2AT - Acoustique, Aérodynamique, Turbulence [Institut Pprime]

Resolvent analysis has demonstrated encouraging results for modeling coherent structures in jets when compared against their data-educed counterparts from high-fidelity large-eddy simulations (LES). We formulate resolvent analysis as an acoustic analogy that relates the near-field forcing to the near-field pressure field and the far-field acoustics. We use an LES database of round, isothermal, Mach 0.9 and 1.5 jets to produce an ensemble of realizations for the acoustic field that we project onto a limited set of resolvent modes. In the nearfield, we perform projections on a restricted acoustic output domain, r/D = [5, 6], while the far-field projections are performed on a Kirchhoff surface comprising a 100-diameter arc centered at the nozzle. This allows the LES realizations to be expressed in the resolvent basis via a data-deduced, low-rank, cross-spectral density matrix. We find that a single resolvent mode reconstructs the most energetic regions of the acoustic field across Strouhal numbers, St = [0 − 1], and azimuthal wavenumbers, m = [0, 2]. Finally, we present a simple function that results in a rank-1 resolvent model agreeing within 2dB of the peak noise for both jets.

Domaines: Milieux fluides et réactifs

Ethan Pickering, Aaron Towne, Peter Jordan, Tim Colonius. Resolvent-based modeling of turbulent jet noise. Journal of the Acoustical Society of America, 2021, 150 (4), pp.2421-2433. ⟨10.1121/10.0006453⟩. ⟨hal-03373323⟩