External Laminar Boundary Layer Simulations Using a High-Fidelity Wall-Modeling Approach

Abstract

Wall-Modeled Large Eddy Simulation (WMLES) is a well-stablished technique for obtaining high-fidelity solutions of turbulent, high Reynolds number flows, with reasonably acceptable computational costs. However, for external flows, the very thin laminar boundary layer developing near the body leading edge imposes quite restrictive mesh resolution requirements, leading to prohibitively high computational costs for practical Reynolds numbers. We propose a wall-modeling approach for the laminar portion of the boundary layer in order to alleviate these costs by reducing the aforementioned mesh resolution requirements. The wall model is based on local self-similar solutions of the boundary layer, and is implemented in the same context of wall-stress models in the WMLES approach. An assessment of the model is done in terms of both pressure and skin friction coefficient distributions along the surface, for an incompressible, fully laminar flow around a NACA 0012 airfoil geometry, with a chord Reynolds number of Re_c = 4500. The results obtained in the simulations using the proposed model are in good agreement with the reference solution, demonstrating the feasibility of the model for external laminar flows.