CFD Simulations of the New MEXICO Rotor Experiment under Yawed Flow

Abstract

This paper describes the conduction of CFD simulations with DLR’s flow solver TAU for comparison with the experimental data that has been used within the third phase of the MexNext-III project. More precisely computations for three different inflow velocities under yawed flow condition have been conducted and compared to the experimental results. Important aspects of the simulations such as a sufficiently long simulation time or a sufficiently small time-step are discussed. At first local flow quantities such as the flow velocity along axial and radial traverses, pressure distributions at four radial stations and normal and tangential forces at these sections are compared. Subsequently the integral rotor quantities i.e. rotor thrust and rotor torque are revised. The integration of the CFD results is performed using the complete surface dataset as well as two subsets.The comparison proves that the agreement can substantially be improved if the subset resembles the experimental dataset. Furthermore the integration of the experimental dataset is reviewed and a weak spot in the current reconstruction procedure of the trailing edge pressure is identified. The proposed alternative provides evidence that further improvements are possible.The final comparison shows an acceptable agreement for the medium and high inflow speed case yielding 0% and 10% difference for integral thrust and 9% and 14% for integral torque. The results for the low inflow speed case are divers: while the agreement for the integral thrust is excellent, it is less satisfactory for the integral torque which amounts to 41%.