Numerical investigation of helicopter rotors in ground effect

This study intends to proof the capability of URANS computations to simulate the helicopter flight in the ground effect flow regime. Hover as well as forward flight cases are computed and compared to experimental data. For both flight conditions several parameter variations, such as ground distance, collective pitch and normalized advance ratio, were examined. Overall a good representation of the flow field structure could be obtained, as well as a satisfying approximation for the thrust coefficient. Furthermore, conclusions could be drawn regarding unsteady effects in the wake and their influence on the brown-out phenomenon. Especially the dynamic fluid movement around the Flow Separation Point is a considerable source of unsteadiness and energy introduced in the brown-out particle movement.

[1]  Narayanan Komerath,et al.  Development of Unsteadiness in a Rotor Wake in Ground Effect , 2003 .

[2]  P. F. Sheridan,et al.  Aerodynamics of Heli-copter Flight near the Ground , 1977 .

[3]  A. T. Conlisk,et al.  The Structure of the Rotor Wake in Ground Effect , 2003 .

[4]  Balakrishnan Ganesh.  Unsteady Aerodynamics of Rotorcraft at Low AdvanceRatios in Ground Effect , 2006 .

[5]  A Betz,et al.  The ground effect on lifting propellers , 1937 .

[6]  Catriona Phillips,et al.  Eulerian Simulation of the Fluid Dynamics of Helicopter Brownout , 2009 .

[7]  Ewald Krämer,et al.  CFD Calculation of a Helicopter Rotor Hovering in Ground Effect , 2013 .

[8]  J. S. Light,et al.  Tip vortex geometry of a hovering helicopter rotor in ground effect , 1993 .

[9]  Mao Sun,et al.  Simulated Flowfields in Near-Ground Operation of Single- and Twin-Rotor Configurations , 2000 .

[10]  David A. Peters,et al.  AN ANALYSIS OF PARTIAL GROUND EFFECT ON THE AERODYNAMICS OF A HELICOPETR ROTOR , 2000 .

[11]  Harry H. Heyson.  Ground Effect for Lifting Rotors in Forward Flight , 1960 .

[12]  James S. Hayden,et al.  The Effect Of The Ground On Helicopter Hovering Power Required , 1976 .

[13]  Devi Prasad Pulla,et al.  A study of helicopter aerodynamics in ground effect , 2006 .

[14]  A. Jameson,et al.  Numerical solution of the Euler equations by finite volume methods using Runge Kutta time stepping schemes , 1981 .

[15]  Rajagopalan,et al.  Rotorwash Prediction Using an Applied Computational Fluid Dynamics Tool , 2004 .

[16]  A. Jameson.  Time dependent calculations using multigrid, with applications to unsteady flows past airfoils and wings , 1991 .

[17]  Richard B. Green,et al.  The flow around a model helicopter main rotor in ground effect , 2012 .

[18]  R. B. Green,et al.  Flow visualisation of the helicopter brown-out phenomenon , 2009, The Aeronautical Journal (1968).

[19]  Baeder,et al.  CFD Validation of Micro Hovering Rotor in Ground Effect , 2010 .

[20]  Ewald Krämer,et al.  Impact of Modelling Approaches on the Prediction of Ground Effect Aerodynamics , 2009 .

[21]  Glen R. Whitehouse,et al.  Modelling Rotor Wakes in Ground Effect , 2004 .

[22]  J. Gordon Leishman,et al.  Predictions of Rotor Performance in Ground Effect Using a Free-Vortex Wake Model , 2005 .

[23]  Nita Darshini Nathan.  The rotor wake in ground effect and its investigation in a wind tunnel , 2010 .

[24]  H. C. Curtiss,et al.  Rotor Aerodynamics in Ground Effect at Low Advance Ratios. , 1984 .

[25]  J. Gordon Leishman,et al.  Fluid Dynamics of Interacting Blade Tip Vortices With a Ground Plane , 2010 .