Towards the Simulation of Trimmed Flight Conditions with Active Engines

A concept is presented for the numerical simulation of trimmed aircraft flight in steady-state conditions under the influence of working engines. An important ingredient in this process is the numerical engine boundary treatment. The engine boundary fluxes were computed following the flux-difference scheme of Roe in combination with an engine-specific definition of the fluid state. An elementary prototype configuration was considered first to verify the steady-state trim procedure in 2D. The desired flight equilibrium was found in a few Newton iterations controlling the engine, the pitch angle and the angle of the horizontal tail plane. Subsequently, a 3D configuration of a generic transport aircraft was considered in cruise conditions. As a first step towards the computation of a steady-state flight equilibrium, the CFD simulation has been performed for an initial configuration with working engines.