Large-eddy simulation of a jet in crossflow using local mesh refinement

A numerical simulation of a turbulent round jet issuing into a laminar crossflow is performed using the method of large-eddy simulation (LES). In order to employ LES efficiently for such multi-scale problems, the code utilises a local mesh refinement (LMR) algorithm and employs a multigrid method to solve the incompressible Navier-Stokes equations. The accuracy of several LMR implementations is assessed for the Taylor-Green vortex problem. Second order accuracy of the LES-LMR code is achieved when ghost cell pressures are computed through an approximate projection method and velocities are computed using quadratic interpolation. Three different LMR strategies for a jet in crossflow are then setup in order to assess the predictive capabilities of the method. The simulations are validated against similar LES and experimental data and excellent agreement with experimental data is found for medium and fine LMR grids, while the coarse LMR grid suffers from over-prediction of the jet centreline speed