An ODE-Based Wall Model for Turbulent Flow Simulations

Abstract

This paper presents a new wall model to compute turbulent boundary layers using the Reynolds-averaged Navier–Stokes equations in high Reynolds number flows. The model solves a two-point boundary value problem for a coupled set of equations for the streamwise velocity and the turbulent viscosity. Since it includes both the pressure gradient and the momentum balance of the full Navier–Stokes system, the ordinary differential equation is valid farther from the wall. We implement the model within a Cartesian cut-cell method and use one-dimensional linelets in each cut cell to avoid the excessive mesh refinement that would otherwise be needed. The linelets are coupled to the outer Cartesian grid in a fully conservative manner, with two-way interaction between the linelets and the background grid. Detailed comparisons of velocity and eddy viscosity with three well-studied examples from the Turbulence Modeling Resource website are presented to demonstrate the model’s performance in two space dimensions, including an example with smooth-body separation. The results show the new model gives excellent results even when the value of the first point is in the wake layer.