Development of a CFD Model of Propeller Slipstream

The growing interest in electric powertrains for aircraft has led to new aircraft designs for air taxis and Unmanned Aerial Vehicles (UAVs), Electric powertrains allow aircraft designers to consider novel propulsion layouts such ones in which many motors/propellers are distributed along the wing's leading edge, known as Distributed Electric Propulsion (DEP). This configuration confers a number of advantages, including the mitigation of airflow separation. Understanding the wake of a propeller can allow us to develop a better understanding of the dynamical behaviour of DEP aircraft, where large parts of the wings are immersed in the propeller slipstream, which can have a large influence on the forces generated by the wing. In the present work, we describe a method for simulating the wake of a given propeller in the OpenFOAM Computational Fluid Dynamics (CFD) package. The propeller model uses body forces within a finite propeller region, acting as a momentum source for fluid passing through it. Simulations using this method were performed for various propeller geometries, rotation rates, and freestream velocities, and results were compared with experimental measurements from the literature, yielding good agreement.