Effect of a Nonlinear Constitutive Relation for Turbulence Modeling on Predicting Flow Separation at Wing-Body Juncture of Transonic Commercial Aircraft

Abstract

This paper presents an improvement in numerical prediction of aerodynamic characteristics for transonic commercial aircraft using the Reynolds-averaged Navier-Stokes equations. With turbulence models base on the Boussinesq eddy-viscosity approximation, the shock-induced flow-separation at wing-body juncture-corner is sometimes overestimated at higher angle-of-attack, which often results in wrong prediction of aerodynamic force and moment of aircraft. To improve it, we focus on effect of anisotropy in the Reynolds stress at the corner flow. A simple nonlinear constitutive relation is employed to introduce the anisotropy of the Reynolds stress for the turbulence models. The obtained results show that the size of the flow separation considerably shrinks with the nonlinear model and fairly good comparison with experimental results. The detailed flow in boundary-layer at the corner is discussed for better understanding of physics that results in the improvement of prediction.