Free Wake Aerodynamic Analysis of Helicopter Rotors.

摘要

A formulation for the free wake analysis of helicopter rotors in incompressible potential flows is presented here. The formulation encompasses both the theory and its numerical implementation. For the case of a single-bladed rotor in hover, the formulation is validated by numerical results which are in good agreement with the generalized wake of Landdgrebe. Extension of the theory to compressible flows is also outlined. These results indicate that the formulation does not require any empirical assumption (such as the rate of contraction of the radius of the wake) in order to avoid numerical instabilities. To our knowledge, the results presented here are the first ones ever obtained not requiring any ad-hoc assumptions in order to avoid such problems. (Author)