Rotor Wake Effects on Hub/Pylon Flow. Volume I. Theoretical Formulation.
Final rept. Jun 75-Sep 77,
AEROSPACE SYSTEMS INC BURLINGTON MASS
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An investigation has been conducted to demonstrate the use of the Greens function method to study rotor wake effects on helicopter hubpylon flow. This report consists of two volumes which document the theoretical formulation and the use of the digital computer program SHAPES Subsonic Helicopter Aerodynamics Program with Effects of Separaton. Volume I presents the theoretical formulation and corresponding numerical procedure for the study of incompressible potential aerodynamics with separated flow. While the formulation is valid for fully unsteady aerodynamics, this report is mainly concerned with rotor aerodynamics. A potential flow aerodynamic program, SHAPES, with suitable rotor wake representation was developed to predict the separation characteristics of arbitrary three-dimensional helicopter configurations. In particular, the effect of the rotor blade wake, blade shank wake, and hub wake in the separation of the flow over a lifting helicopter in forward flight is analyzed. The present method has potential application in the design of helicopters because it provides an analytical capability which can be used to develop low-drag profile as well as to explore problem areas. Extensive numerical results obtained from Program SHAPES demonstrated the flexibility and accuracy of the method. These results are in excellent agreement with existing data. Author
- Fluid Mechanics