Turbulence model and numerical scheme assessment for buffet computations

Abstract

International audienceThe prediction of shock-induced oscillations over transonic rigid airfoils is important for a better understanding of the buffeting phenomenon. The unsteady resolution of the Navier-Stokes equations is performed with various transport-equation turbulence models in which corrections are added for nonequilibrium flows. The lack of numerical efficiency due to the CFL stability condition is circumvented by the use of a wall law approach and a dual time stepping method. Moreover, various numerical schemes are used to try and be independent of the numerical discretization. Comparisons are made with the experimental results obtained for the supercritical RA16SC1 airfoil. They show the interest in using the SST correction or realizability conditions to get correct predictions of the frequency, amplitude and pressure fluctuations over the airfoil

Experimental validation of two depth‐averaged turbulence models

“…The use of the Newton Raphson's method has been of utility to greatly accelerate the convergence. On the other hand, Spalding [33] (also reported in [34,35]) obtained an alternative expression for the law of the wall, based on Taylor series, valid for both the viscous sublayer and the logarithmic zone,…”

Aeroelastic Responses of Spring-suspended Airfoil Systems in Transonic Buffeting Flows

“…Numerical CFD-based shock-buet predictions and the inuence of dierent numerical parameters and turbulence models on the computed buet characteristics were the subjects of several studies [8,9,1116]. Most of the studies were carried out using several subsonic and supercritical 2D airfoils.…”

“…Several recent studies used CFD solutions to study either the shock-buet phenomenon (in which the airfoil itself does not oscillate [8,9,1116]) or the transonic aeroelastic problem, in which the airfoil is spring-suspended but there is no buet [17,18]. Recent studies by the authors [10,19,20] presented Navier-Stokes simulations of airfoil responses to prescribed motions (plunge, pitch, and trailing-edge ap rotation) about ow conditions that exhibit shockbuet.…”

The interaction between flutter and buffet in transonic flow

“…Lee [6,42] has proposed the self-excited-feedback model to explain the mechanism, which assumes that the sound wave caused by the free shear layer of the trailing edge travels upstream on the upper surface and forms a feedback together with the shock oscillation, thus leading to an unsteady flow. Transonic buffet is an unstable aerodynamic phenomenon; thus, most of the numerical research is performed for the stationary wing or airfoil [43][44][45][46][47][48][49][50][51][52][53]. Many researchers utilize the unsteady Reynoldsaveraged Navier-Stokes (URANS) methods and combine various turbulence models to simulate transonic buffet flows 4.…”

“…Based on URANS method, Goncalves[43] studies the effect of turbulence model and numerical scheme on the transonic buffet simulation, and Thiery[45] assesses the adequacy of time step and boundary condition for transonic buffet. Raveh[54][55][56] conducts a series of research on transonic buffeting phenomena based on URANS method with SA turbulence model.…”