Implicit Large Eddy Simulation of a wingtip vortex at Re c =1.2 · 10 6 Jean-Eloi W. Lombard * , David Moxey † , Julien F. A. Hoessler ‡ , Sridar Dhandapani § , Mark J. Taylor ¶ , Spencer J. Sherwin k Abstract In this article we present recent developments in numerical methods for performing a Large Eddy Simulation (LES) of the formation and evolution of a wingtip vortex. The development of these vortices in the near wake, in combination with the large Reynolds numbers present in these cases, make these types of test cases particularly challenging to investigate numerically. We first give an overview of the Spectral Vanishing Viscosity–implicit LES (SVV-iLES) solver that is used to perform the simulations, and highlight techniques that have been adopted to solve various numerical issues that arise when studying such cases. To demonstrate the method’s viability, we present results from numerical simulations of flow over a NACA 0012 profile wingtip at Rec =1.2 · 10 6 and compare them against experimental data, which is to date the highest Reynolds number achieved for a LES that has been correlated with experiments for this test case. Our model correlates favorably with experiment, both for the characteristic jetting in the primary vortex and pressure distribution on the wing surface. The proposed method is of general interest for the modeling of transitioning vortex dominated flows over complex geometries. Nomenclature c = Wing chord b = wingspan A = aspect ratio of the wing Re c = Reynolds number based on wing chord x,y,z = Carterisan coordinates, Δx = local cell size u,v,w = Cartesian velocity components y + = distance from surface in wall units t = time t c = convective time associate to chord Δt = time-step l 0 = length scale associate to largest eddies η = Kolmogorov length scale τ = Kolmogorov time scale p = pressure p = far-field pressure U ∞ = inflow velocity ρ ∞ = density C p = Pressure coefficient ν = kinematic viscosity α = angle of attack k = mode M = cut-off mode of the SVV filter P = P = M - 1 polynomial order of the spectral element. ε SV V = diffusion from the SVV filter ˆ Q = SVV kernel 1 Introduction Understanding the development and growth of wingtip vortices over lifting surfaces is an ongoing research topic both in academia and industry. From an academic perspective, fundamental open questions remain, such as * Graduate Research Assistant, Department of Aeronautics, Imperial College, London, UK; jean-eloi.lombard12@imperial.ac.uk (Corresponding Author). † Research Associate, Aeronautics, Department of Aeronautics, Imperial College, London, UK ‡ Senior CFD Engineer, CFD Technology, McLaren Racing, McLaren Technology Center, Woking, UK § Team Leader, CFD Technology, McLaren Racing, McLaren Technology Center, Woking, UK ¶ Principle Aerodynamicist, McLaren Racing, McLaren Technology Center, Woking, UK k Professor of Computational Fluid Mechanics, Aeronautics. 1 arXiv:1507.06012v1 [physics.flu-dyn] 21 Jul 2015