Large-Eddy Simulations of a Cylindrical Film Cooling Hole

Large-eddy simulations are used to explore the unsteady jet-in-crossflow interactions arising from discrete hole film cooling from a cylindrical hole. The numerical grids are created using GridPro and solved in OpenFOAM. A recycling-rescaling technique is used to generate a realistic turbulent incoming boundary layer upstream of injection. The simulations match the conditions of an experiment in the open literature for the robust validation of the numerical solution and turbulence modeling. The current study tests the ability of large-eddy simulations in predicting film cooling flows using detailed experimental measurements. The large-eddy simulation results compared favorably with the experimental data except in areas close to the injection site and close to the wall. Grid resolution is discussed in terms of the percent turbulent kinetic energy resolved and related to the success of the large eddy simulation predictions in different regions of the jet. No substantial benefit was seen by using a dynamic Smagorinsky model for the subgrid turbulent heat fluxes instead of a constant subgrid Prandtl number. The trajectories, spreading rates, and large turbulent structures of the jet are discussed in terms of the hydrodynamic parameters such as velocity ratio and momentum ratio.