Linear Reduced-Order Model for Unsteady Aerodynamics of an L-Shaped Gurney Flap

The purpose of the work is to investigate the mechanism that underlies the development of unsteady loads by a novel L-shaped Gurney flap conceived to perform vibration control on rotorcraft blades. The device is combination of a spoiler with a Gurney flap. Exploiting the capabilities of a Reynolds-averaged Navier–Stokes flow solver employing the overset mesh approach, several numerical simulations are carried out at low Mach number. These simulations are used to develop a physically based linear reduced-order model in the frequency domain for the unsteady lift and pitching moment of a NACA 0012 airfoil, considering as input the pitch and plunge harmonic oscillations of the airfoil, together with the oscillations of the L-shaped Gurney flap. The aerodynamic assessment of the L-tab shows that the behavior of the loads can be predicted using an equivalent flat-plate model to represent the airfoil composed by three segments: the first representing the fixed part of the airfoil, the second representing the lon...

[1]  Russell M. Cummings,et al.  Numerical Investigation of an Airfoil with a Gurney Flap , 1998 .

[2]  Ashok Gopalarathnam,et al.  Drag Reduction on Aircraft Configurations with Adaptive Lifting Surfaces , 2008 .

[3]  J. G. Leishman,et al.  Unsteady aerodynamics of a flapped airfoil in subsonic flow by indicial concepts , 1995 .

[4]  Li Liu,et al.  Computational Study of Microflaps with Application to Vibration Reduction in Helicopter Rotors , 2011 .

[5]  Lawrence Lee,et al.  Effect of Gurney Flap on Unsteady Wake Vortex , 2007 .

[6]  R. Liebeck.  Design of Subsonic Airfoils for High Lift , 1976 .

[7]  Earl P. N. Duque,et al.  Numerical Investigation on the Aerodynamics of Oscillating Airfoils with Deployable Gurney Flaps , 2010 .

[8]  Tim Lee,et al.  Lift enhancement and flow structure of airfoil with joint trailing-edge flap and Gurney flap , 2011 .

[9]  Israel J Wygnanski,et al.  Dynamic Stall Control by Periodic Excitation, Part 2: Mechanisms , 2001 .

[10]  Lakshmi N. Sankar,et al.  Aerodynamic Evaluation of Miniature Trailing-Edge Effectors for Active Rotor Control , 2010 .

[11]  E. A. Gillies,et al.  Alleviation of Airfoil Dynamic Stall Moments via Trailing-Edge-Flap Flow Control , 2004 .

[12]  Jose Palacios,et al.  Active Gurney Flaps: Their Application in a Rotor Blade Centrifugal Field , 2014 .

[13]  Inderjit Chopra,et al.  Robust individual blade control algorithm for a dissimilar rotor , 2002 .

[14]  George N. Barakos,et al.  Assessment of CFD methods against experimental flow measurements for helicopter flows , 2012 .

[15]  Bruce L. Storms,et al.  Lift enhancement of an airfoil using a Gurney flap and vortex generators , 1993 .

[16]  Olivier A. Bauchau,et al.  A CFD–CSD coupled-analysis of HART-II rotor vibration reduction using gurney flaps , 2010 .

[17]  Jinjun Wang,et al.  Gurney flap—Lift enhancement, mechanisms and applications , 2008 .

[18]  Earl H. Dowell,et al.  Aerodynamic Flow Control of an Airfoil with Small Trailing-Edge Strips , 2006 .

[19]  Aaron Anthony Cusher,et al.  A design and analysis approach for drag reduction on aircraft with adaptive lifting surfaces , 2008 .

[20]  J. Kentfield,et al.  The potential of Gurney flaps for improving the aerodynamic performance of helicopter rotors , 1993 .

[21]  P. Spalart.  A One-Equation Turbulence Model for Aerodynamic Flows , 1992 .

[22]  Friedrich K. Straub,et al.  Rotors with Trailing Edge Flaps: Analysis and Comparison with Experimental Data , 1998 .

[23]  George A. Lesieutre,et al.  Miniature trailing-edge effectors for rotorcraft performance enhancement , 2007 .

[24]  V. Venkatakrishnan,et al.  IMPLICIT METHOD FOR THE COMPUTATION OF UNSTEADY FLOWS ON UNSTRUCTURED GRIDS , 1995 .

[25]  Joseph Katz,et al.  AERODYNAMICS OF RACE CARS , 2006 .

[26]  Kevin Standish,et al.  Two-Dimensional Wind Tunnel and Computational Investigation of a Microtab Modified Airfoil , 2005 .

[27]  J. Gordon Leishman,et al.  Principles of Helicopter Aerodynamics , 2000 .

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

[29]  Tim Lee,et al.  Oscillating Wing Loadings with Trailing-Edge Strips , 2006 .

[30]  Roy Y. Myose,et al.  An experimental investigation of Gurney flaps on a GA(W)-2 airfoil with 25 percent slotted flap , 1996 .

[31]  C. P. van Dam,et al.  Computational Analysis of a Microtab-Based Aerodynamic Load Control System for Rotor Blades , 2005 .

[32]  W. Zhang,et al.  Experimental investigations on the application of lift enhancement devices to forward-swept aircraft model , 2006 .

[33]  Inderjit Chopra,et al.  Wind-Tunnel Testing of Rotor with Individually Controlled Trailing-Edge Flaps for Vibration Reduction , 2008 .

[34]  I. H. Abbott,et al.  Theory of Wing Sections , 1959 .

[35]  Roy Y. Myose,et al.  Gurney Flap Experiments on Airfoils, Wings, and Reflection Plane Model , 1998 .

[36]  Peipei Zhang,et al.  Numerical Simulation of Gurney Flap on RAE-2822 Supercritical Airfoil , 2011 .

[37]  B. V. Leer,et al.  Towards the ultimate conservative difference scheme V. A second-order sequel to Godunov's method , 1979 .

[38]  Lance W. Traub,et al.  Exploratory Investigation of Geometry Effects on Gurney Flap Performance , 2007 .

[39]  Walid Khier,et al.  CFD prediction of air flow past a full helicopter configuration , 2012 .

[40]  David W. Hurst,et al.  Aerodynamics of Gurney Flaps on a Single-Element High-Lift Wing , 2000 .

[41]  T. Theodorsen.  General Theory of Aerodynamic Instability and the Mechanism of Flutter , 1934 .

[42]  Giuseppe Gibertini,et al.  Experimental investigation of a trailing edge L-shaped tab on a pitching airfoil in deep dynamic stall conditions , 2014 .

[43]  Mark D. Maughmer,et al.  Experimental Investigation of Gurney Flaps , 2008 .

[44]  H G Kussner,et al.  The oscillating wing with aerodynamically balanced elevator , 1941 .

[45]  Mark D. Maughmer,et al.  Unsteady Aerodynamics of Miniature Trailing-Edge Effectors Based on Indicial Methods , 2011 .

[46]  Earl H. Dowell,et al.  Aerodynamic Loading for an Airfoil with an Oscillating Gurney Flap , 2007 .

[47]  James G. Coder,et al.  Experimental Investigation into the Effect of Gurney Flaps on Various Airfoils , 2013 .

[48]  Kai Richter,et al.  Experimental investigation of trailing-edge devices at transonic speeds , 2002 .

[49]  Jinjun Wang,et al.  Influences of Mounting Angles and Locations on the Effects of Gurney Flaps , 2003 .

[50]  B. V. Leer,et al.  Towards the ultimate conservative difference scheme. IV. A new approach to numerical convection , 1977 .

[51]  Inderjit Chopra,et al.  Swashplateless Helicopter Rotor System with Trailing-Edge Flaps for Flight and Vibration Controls , 2006 .

[52]  Guy Dumas,et al.  Gurney flap effects and scaling for low-speed airfoils , 1995 .

[53]  Jun Wang,et al.  Experimental investigations on the effects of divergent trailing edge and Gurney flaps on a supercritical airfoil , 2007 .

[54]  Tianshu Liu,et al.  Thin-Airfoil Theoretical Interpretation for Gurney Flap Lift Enhancement , 2007 .