Direct Noise Computation of the Turbulent Flow Around a Zero-Incidence Airfoil

Abstract

A large eddy simulation of the flow around a NACA 0012 airfoil at zero incidence is performed at a chord-based Reynolds number of 500,000 and a Mach number of 0.22. The aim is to show that high-order numerical schemes can successfully be used to perform direct acoustic computations of compressible transitional flow on curvilinear grids. At a Reynolds number of 500,000, the boundary layers around the airfoil transition from an initially laminar state to a turbulent state before reaching the trailing edge. Results obtained in the large eddy simulation show a well-placed transition zone and turbulence levels in the boundary layers that are in agreement with experimental data. Furthermore, the radiated acoustic field is determined directly by the large eddy simulation, without the use of an acoustic analogy. Third-octave acoustic spectra are compared favorably with experimental data.

A study of infrasound propagation based on high-order finite difference solutions of the Navier-Stokes equations

“…Examples of 2D acoustic diffraction and aeroacoustic flows successfully simulated with the solver described in this work can be found in Marsden et al 34 and Berland et al 27 The same methodology has been applied to numerous aeroacoustic studies in 3D, [35][36][37][38] and the generalization of the currently described solver to three dimensions should pose no difficulties other than that of the computational cost of the resulting 3D computations.…”

A shock-capturing methodology based on adaptative spatial filtering for high-order non-linear computations

“…Time integration is performed using a six-stage second-order low-storage Runge-Kutta algorithm displaying low-dispersion and low-dissipation in the Fourier space [7]. These methods have been successfully implemented in previous studies to perform direct noise computations for configurations such as subsonic and supersonic jets [12,52,53], and flows around an airfoil [54].…”

Compressible-Flow DNS with Application to Airfoil Noise

“…[10] used DNS to investigate the noise sources in a low-Reynolds-number turbulent jet at Mach 0.9, and one of the first simulations of wall-bounded flows followed, with [13] considering sound radiation in turbulent channels. A few years later, [36] simulated turbulent flow over a trailing edge and the associated noise generation in order to investigate the accuracy of classical trailing edge theories, and direct noise simulations of full airfoil configurations have followed, using both DNS [e.g., 14] or Large-Eddy Simulations in order to increase the chord-Reynolds number to practical values [26,42].…”