Steady and Unsteady Numerical Simulation of a Bent Intake Geometry

A broad range of numerical flow simulations are carried out during the design phase of a highly bent intake geometry. The main aim is to evaluate the aerodynamic characteristics of a projected wind tunnel model and an estimation of mechanical loads for the structural dimensioning. The numerical setup using the TRACE code is validated first against comprehensive experimental data of a NASA s-duct test case. Three different turbulence models are found to be capable of reproducing the main flow features that occur in bent intake ducts with an acceptable accuracy. The following steady simulations of the symmetric wind tunnel model show asymmetric flow solutions and convergence problems for two of the three turbulence models. URANS computations are therefore carried out including a sensitivity study towards time-step size and domain volume. The unsteady results using the three different turbulence models still exhibit significant deviations concerning mechanical loads and duct performance. A safety margin is thus estimated from the unsteady data to be used for the construction and testing of the wind tunnel model.