Calculation of Three-Dimensional Unsteady Transonic Flows Past Helicopter Blades.
NATIONAL AERONUATICS AND SPACE ADMINISTRATION MOFFETT FIELD CA AMES RESEARCH CENTER
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A finite difference code for predicting the high-speed flow over the advancing helicopter rotor is presented. The code solves the low-frequency, transonic small disturbance equation and is suitable for modeling the effects of advancing blade unsteadiness on blades of nearly arbitrary planform. The method employs a quasi-conservative mixed differencing scheme and solves the resulting difference equations by an alternative direction scheme. Computed results show good agreement with experimental blade pressure data and illustrate some of the effects of varying the rotor planform. The flow unsteadiness is shown to be an indispensible part of a transonic solution. It is also shown that, close to the tip at high advance ratio, cross-flow effects can significantly affect the solution. Author
- Fluid Mechanics