Nonlinear Helicopter Rotor Lifting Surface Theory. Part III.
Final rept. 1 Jan-31 Mar 75,
WEST VIRGINIA UNIV MORGANTOWN DEPT OF AEROSPACE ENGINEERING
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The Greens function approach for the subsonic compressible potential flow over a helicopter rotor in hover or steady state vertical climb was examined. Several methods of approach were taken to derive the Greens function. An attempt to derive the Greens function directly from the differential equation written in the non-inertial coordinate system was not successful. However, since the Greens function was known in the inertial system, a transformation of the integral equation for the velocity potential in this system was transformed successfully to the blade fixed coordinate system. The resulting integral equation involves surface derivatives which preclude the use of previous numerical schemes for its solution. A second part of the report includes the results of the second iteration for the force-free wake of a rotor in hover.
- Fluid Mechanics