The Spalart-Allmaras and the Menter SST k-ω turbulence models are shown to have the undesirable characteristic that, for fully turbulent computations, a transition region can occur whose extent varies with grid density. Extremely fine two-dimensional grids over the front portion of an airfoil are used to demonstrate the effect. As the grid density is increased, the laminar region near the nose ...

This paper presents a time-accurate procedure for computing unsteady aerodynamic forces on wings with a full-span oscillating control surface by using sheared grids. In this procedure, the flow is computed by solving the unsteady Reynolds-Averaged Navier-Stokes (RANS) equations in conjunction with the one-equation Spalart-Allmaras turbulence model. A module to model control surface oscillations...

Abstract The new term belongs in the “basic,” free-shear-flow part of Spalart–Allmaras (SA) model, and extends an idea Secundov team, incorporated ν t -92 model. It detects transverse curvature distribution eddy viscosity $$ \tilde{\nu } ν ~ , so that it is passive tw...

A fast Newton-Krylov algorithm is presented for solving the compressible Navier-Stokes equations on structured multi-block grids with application to turbulent aerodynamic flows. The oneequation Spalart-Allmaras model is used to provide the turbulent viscosity. The optimization of the algorithm is discussed. ILU(4) is suggested for a preconditioner, operating on a modified Jacobian matrix. An ef...

The objective of this paper is to study the effect of an unsteady moving heat source on the aerodynamic performance of an NACA 0012 airfoil section, with particular focus on the lift and drag coefficients. The compressible Navier–Stokes equations are solved using a finite volume method as well as Spalart-Allmaras Model for turbulence simulation. The heat source periodically moves over the lower...