Imposing Realistic Unsteady Flow Structures Though Inflow Boundary Conditions

Abstract

The quality of flow simulations relies on the realism and quality of boundary conditions. Based on the method of characteristics, we present a formulation to introduce unsteady coherent flow structures at the inlet boundary of compressible flow computations. For this, a few proper orthogonal modes are used to represent the large-scale flow structures, which have low memory requirements and describe the unsteady nature. Further, we use the neglected higher-order modes to formulate informed boundary conditions for the turbulence model transport variables. Typical performance verifications of boundary conditions' bias error and reflective properties are presented. The functionality of the inflow boundary condition is demonstrated by propagating flow structures through nozzle guide vanes and a consecutive rotor blade row.