Implicit large eddy simulation of acoustic loading in supersonic turbulent boundary layers

Abstract

This paper investigates the accuracy of implicit Large Eddy Simulation in the prediction of acoustic phenomena associated with pressure fluctuations within a supersonic turbulent boundary layer. We assess the accuracy of implicit Large Eddy Simulation against Direct Numerical Simulation and experiments for attached turbulent supersonic flow with zero-pressure gradient, and further analyze and discuss the effects of turbulent boundary layer pressure fluctuations on acoustic loading both at the high and low frequency regimes. The results of high-order variants of the simulations show good agreement with theoretical models, experiments, as well as previously published Direct Numerical Simulations

Computational aeroacoustics beneath high speed transitional and turbulent boundary layers

“…We have employed the iLES approach in the framework of the in-house block-structured mesh code CNS3D [22,23,24] that solves the full Navier-Stokes equations using a finite volume Godunov-type method for the convective terms, whose inter-cell numerical fluxes are calculated by solving the Riemann problem using the reconstructed values of the primitive variables at the cell interfaces. A one-dimensional swept unidirectional stencil is used for reconstruction.…”

“…A synthetic turbulent inflow boundary condition is used to produce a freestream flow with a superimposed random turbulence. The synthetic turbulent inflow boundary condition is based upon the digital filter (DF) method documented in [38,39,40] and, specifically validated in the framework of the present iLES code CNS3D in [41,42,23]. According to DF, instead of using a white-noise random perturbation at the inlet, energy modes within the Kolmogorov inertial range scaling with k −5/3 , where k is the wavenumber, are introduced into the turbulent boundary layer.…”

Wall-pressure spectra models for supersonic and hypersonic turbulent boundary layers

“…The iLES data has been calculated in the framework of the high-order code CNS3D, which has been validated in several iLES studies of transitional and turbulent flows [12,13,14,10,11,15]. CNS3D is based on the HLLC Riemann solver [16] and a ninth-order WENO scheme [17] for the advective terms, second-order discretisation for the viscous terms and the third-order accurate Runge-Kutta method for the time integration [18].…”

“…In this paper, the qualitative accuracy of several WPSM is assessed for supersonic and hypersonic TBL. WPSM are compared with data that has been obtained from implicit Large Eddy Simulations (iLES) [10,11], which can be considered as an under-resolved Direct Numerical Simulation (DNS). Furthermore, compressibility corrections are proposed that significantly improve the accuracy of spectra models.…”

Physical insight into a Mach 7.2 compression corner flow

“…iLES are used in the framework of the high-order code CNS3D that has been successfully applied to a range of turbulent studies, including supersonic and hypersonic transitional and turbulent flows. [8][9][10] CSN3D employs block-structured grids and solves the full Navier-Stokes equations using a finite volume Godunovtype method for the convective terms. The "Harten, Lax, van Leer, and (the missing) Contact" (HLLC) Riemann solver 11 in conjunction with a ninth-order Weighted-Essentially-Non-Oscillatory (WENO) scheme 12 are used for the advective terms.…”