Computations and Experiments on Flow Physics of Edgewise Ducted Fan Air Vehicles

A coupled blade element theory - CFD method was developed for the study of dual ducted fan vehicles in edgewise forward flight. This coupled method was pursued in the interest of keeping computational costs low to allow for rapid design and preliminary analysis while increasing fidelity of the solution by using a non-uniform thrust distribution. The BET-CFD coupled method was run and compared to a momentum source CFD, assuming ideal rotor performance, a fully resolved rotor CFD solution and to experiments. It was found that the coupled solution was able to reproduce flow phenomena such as the lip separation and the distorted inflow field quite accurately. While improvement was seen in the high speed forward flight simulation as compared to the momentum source computations, the method failed to produce accurate and reliable lift and drag results over the entire flight regime. Further refinement is required in the implementation of the blade element theory into the coupled loop in order to improve the fidelity of the computations.