A numerical procedure has been developed for the prediction of the three-dimensional unsteady aerodynamic response of a helicopter rotor during self-generated blade-vortex interactions (BVI). Pertinent vortex wake parameters (e.g., spatial and temporal trajectories, strenghts) were computed using the lifting-line rotor/helicopter trim code CAMRAD/JA. In this code, tracking of the near-field BVI vortex-wake segments were accomplished using a new 'box' technique which involves tracking all tip vortex elements lying inside a user-specified box-like domain which encloses the rotor. Unsteady blade surface pressures were then predicted using a modified version (designated FPRBVI) of the full potential rotor code FPR (v 2.1). Two approaches were used to model vortex-induced effects in the FPRBVI solver; the efficient surface or 'transpiration' approach, and the more comprehensive split potential approach. The numerical procedure was used to predict the unsteady aerodynamic response of the one-seventh scale two-bladed AH-1G OLS model rotor and a United Technologies Corporation 17.5 % scale four-bladed model rotor during self-generated BVI. Accuracy of the numerical procedure was assessed using wind tunnel data.
A consistent approach for modeling the aerodynamics of self-generated rotor blade-vortex interactions
Ein konsistentes Verfahren zur aerodynamischen Modellierung von selbsterzeugten Rotorblatt-Wirbel-Interaktionen
Journal of the American Helicopter Society ; 41 , 2 ; 74-84
1996
11 Seiten, 10 Bilder, 24 Quellen
Article (Journal)
English
Aerodynamics and Acoustics of Rotor Blade-Vortex Interactions
Online Contents | 1995
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