AIAA 2000-2475 Rotorcraft Retreating Blade Stall Control

Abstract * Flow control to avoid or delay rotorcraftretreating blade stall can be an enabling technologyfor future high performance rotorcraft. Aerodynamicexperiments and computations have indicated thatappropriate unsteady excitation can delay boundarylayer separation and stall on airfoils. Work is inprogress to determine the control requirements forhelicopter rotor blades at full scale Mach numbers,Reynolds numbers, and with unsteady pitchingmotions. Compact, powerful, and efficient flowactuation and control systems will be needed. Threeactuation concepts were favorably evaluated duringinitial studies: electromechanical directed syntheticjets (DSJ), periodic flow modulation, and plasmaactuation. Electromechanical DSJ and plasmaactuators are being developed further and will beevaluated in full scale pitching blade sectionexperiments. These experiments will determine therequired control authority, validate the actuatorconcepts, and study open and closed loop controlapproaches. Computational studies are beingperformed of the combined external and actuator flowfields to determine preferred actuation geometries andoperating points. System analyses are being used toquantify the benefits for representative aircraftconfigurations and missions.Copyright y2000 by United TechnologiesCorporation. Published by the American Institute ofAeronautics and Astronautics, Inc., withPermission.

[1]  Thomas F. Brooks,et al.  The Effects of Higher Harmonic Control on Blade-Vortex Interaction Noise and Vibration , 1993 .

[2]  Andrzej Banaszuk,et al.  Adaptive control of combustion instability using extremum-seeking , 2000, Proceedings of the 2000 American Control Conference. ACC (IEEE Cat. No.00CH36334).

[3]  Mukund Acharya,et al.  Control of the dynamic-stall vortex over a pitching airfoil by leading-edge suction , 1993 .

[4]  Israel J Wygnanski,et al.  Parameters affecting dynamic stall control by oscillatory excitation , 1999 .

[5]  Soogab Lee,et al.  Dynamic Stall Control for Advanced Rotorcraft Application , 1995 .

[6]  C. Mayoux,et al.  Experimental and theoretical study of a glow discharge at atmospheric pressure controlled by dielectric barrier , 1998 .

[7]  T. Corke,et al.  Controlled experiments on instabilities and transition to turbulence in supersonic boundary layers , 1997 .

[8]  Peretz P. Friedmann,et al.  Vibration reduction in rotorcraft using active control - A comparison of various approaches , 1995 .

[9]  Steven P. Grohsmeyer.  Numerical investigation of the effect of leading edge geometry on dynamic stall of airfoils , 1991 .

[10]  K. W. Noonan,et al.  Design And Evaluation Of Multi-Element Airfoils For Rotorcraft , 1999 .

[11]  U. Ingard.  On the Theory and Design of Acoustic Resonators , 1953 .

[12]  D. C. McCormick,et al.  BOUNDARY LAYER SEPARATION CONTROL WITH DIRECTED SYNTHETIC JETS , 2000 .

[13]  A. Seifert,et al.  Oscillatory Control of Separation at High Reynolds Numbers , 1999 .

[14]  William G. Bousman,et al.  A Qualitative Examination of Dynamic Stall from Flight Test Data , 1997 .

[15]  Colin R. Theodore,et al.  Effects of Higher Harmonic Control on Rotor Performance , 2000 .

[16]  Miguel Visbal.  Effect of compressibility on dynamic stall of a pitching airfoil , 1988 .

[17]  K. Mcalister,et al.  The effect of a leading-edge slat on the dynamic stall of an oscillating airfoil , 1983 .

[18]  Patrick Reisenthel,et al.  Control of Separated Flows Using Forced Unsteadiness , 1985 .

[19]  Michael Amitay,et al.  Aerodynamic Flow Control Using Synthetic Jet Technology , 1998 .

[20]  L. Carr,et al.  Compressibility effects on dynamic stall , 1996 .

[21]  P. Lorber,et al.  Computational and experimental studies of compressible dynamic stall , 1990 .

[22]  Peter Lorber,et al.  Compressibility effects on the dynamic stall of a three-dimensional wing , 1992 .

[23]  Peter F. Lorber,et al.  Airfoil dynamic stall at constant pitch rate and high Reynolds number , 1987 .