Coupled CFD-CAA Simulation of the Noise Generated by a Hot Supersonic Jet Impinging on a Flat Plate with Exhaust Hole

Abstract

In this study, the methodology relying on LES for the generation of the acoustic sources coupled with an Euler solver for their propagation, previously developed for a free hot supersonic jet, has been applied to a similar jet but impinging on a plate with an exhaust hole. Attention has been paid to the turbulent state of the nozzle exit boundary layer, which is a key parameter for jet noise simulation.

Large-eddy simulations of the flow and acoustic fields of a rocket jet impinging on a perforated plate

“…They are linked to the presence of six shock cells, which are progressively damped by the turbulent mixing. The mean value of the length L s of the first four cells is close to 4.6r 0 , in agreement with the experiments of Piantanida & Berterretche [9] and the simulations of Troyes et al [3,29] and Langenais et al [26]. In order to estimate the shock cell length, Tam & Tanna [30] proposed the following formula based on the work of Pack [31] L s = πD j β µ 1 (2) where β = M 2 j − 1 and µ 1 = 2.40483 is the first zero of the zero-order Bessel function of the first kind.…”

“…They highlighted the presence of another significant noise component in the upstream direction, generated by the impingement of the jet turbulent structures on the hole edges. This component was also visualized in the acoustic far field of a jet at a Mach number of 3.1 impinging on a perforated plate computed by Troyes et al [3]. Nevertheless, it is still unclear which of the two upstream components, the impingement noise and the reflections of the Mach waves, dominates.…”

“…In particular, the ideally expanded Mach number is equal to M j = 2.9. The ejection parameters of the jets have been chosen to match those of a mixed hydrogen-air jet considered in some experiments conducted at the MARTEL facility [9] and in the simulations of Troyes et al [3]. The jet static temperature T e is set so that the ratio c e /c 0 between the local and the ambient sound speeds is the same as that in the hydrogen-air jet, following the approach of Doty & McLaughlin [10].…”

“…In order to analyze noise generation during a rocket launch, a simplified geometry of a launch pad, namely a jet impinging on a plate with a hole, can be considered. Such a configuration has been investigated numerically for hot overexpanded supersonic jets, typical of rocket jets, for nozzle-to-plate distances L between 15D and 20D, where D = 2r 0 is the nozzle diameter [1][2][3]. In particular, Kawai et al [1] studied the impingement of an overexpanded jet at an exit Mach number of 3.66 on a plate with a hole using an axisymmetric Large-Eddy Simulation (LES).…”

Large-Eddy Simulations of Round Jets at a Mach Number of 0.9 Impinging on a Plate with and without a Hole

“…However, no investigation was focused on this downstream radiation or on the effects of the hole on the feedback properties, namely the frequency and intensity of the tones. More recently, jets impinging on a plate with a hole have been studied for a Mach number of 3.7 by Tsutsumi et al [15] and for a Mach number of 3.1 by Troyes et al [16]. No feedback loop was observed for these very high Mach numbers.…”