Generalized wake geometry for a helicopter in forward flight and effect of wake deformation on airloadsAn analytical investigation was conducted to develop a first level generalization of the predicted distorted wake geometry of a helicopter rotor in level steady forward flight and to demonstrate the influence of wake deformation on the prediction of rotor airloads. Distortions of the tip vortex relative to the classical undistorted geometry are generalized in terms of vortex age, blade azimuth, advance ratio, thrust coefficient, and number of blades for a representative rotor. A computer module and charts were developed for approximating wake geometry and identifying wake boundaries and locations of blade-vortex passage. Predicted H-34 airloads for several inflow/wake models are compared with data for selected flight conditions. The occurrence of close blade-vortex passages and the high sensitivity of predicted airloads to small deviations of blade to tip vortex distance demonstrate the requirement for improved blade-vortex interaction models. The airload correlations indicate that refined distorted wake methodology has the potential to provide more accurate airload prediction.
Document ID
19850049835
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Egolf, T. A. (United Technologies Research Center East Hartford, CT, United States)
Landgrebe, A. J. (United Technologies Research Center East Hartford, CT, United States)
Date Acquired
August 12, 2013
Publication Date
January 1, 1984
Subject Category
Aerodynamics
Meeting Information
Meeting: American Helicopter Society, Annual Forum