Investigation of S-shaped intake aerodynamics using computational fluid dynamics
Flows in the s-shaped intake (Royal Aircraft Establishment intake model 2129-M2129) have been simulated and analysed using Computational Fluid Dynamics (CFD). Various flows have been simulated from steady through-flow for validation and verification, steady flows at a variety of angles of pitch and yaw, and the unsteady flow of surge wave propagation following the application of surge signatures at the engine face. Reynolds Averaged Navier-Stokes (RANS) simulations have been considered using the SA, k- ω and SST turbulence models where possible. The freestream Mach number was fixed at 0.21 and the Reynolds number based on the non-dimensional engine face diameter was 777,000 for all cases. The Glasgow flow solver PMB was used and second order accuracy was achieved in both space and time. Grid and time step convergence studies verified the numerical method, the grids being of the structured multi-block type. A comprehensive validation study was undertaken on the steady through-flow problem. Previously examined low and high mass flow cases were studied. It was found that the low mass flow results compared well with previous computational solutions. Problems however were encountered in the quantitative prediction of the secondary flow when compared with experiment however the SST model did quantitatively predict this. The high mass flow case proved more challenging. Solutions predicted two different flow regimes depending on the turbulence model used. It was found that the SST model provided a good matched with the primary set of experimental data. Confidence in this result was gained as it also performed well in the low mass flow case and also as it has shown previous improvements in the prediction of separation in flows with strong adverse pressure gradients.