3D Euler Calculations of Multibladed Rotors in Hover: Investigation of the Wake Capturing Properties

Abstract

The 3D flowfield of a hovering rotor is calculated solving the Euler equations. Performing a grid refinement study it is demonstrated that an Euler method is able to capture the wake and vortices of a hovering rotor without any wake modelling. Accurate prediction of these rotational flow field phenomena needs fine grids with a high resolution in the complete region of the wake system. Additionally, high accuracy for the treatment of all numerical boundaries, which affect the vortex wake, is required. On the other hand, the investigations have shown that airloads are less effected by a more detailed resolution of the wake system. A second part of the study is concerned with wake capturing properties on block boundaries, especially on inner boundaries of overlapping grids. Overlapping grids are very attractive for the computation of a rotor in lifting forward flight or a rotor-body flowfield in hover.