Free-vortex filament methods for the analysis of helicopter rotor wakes

Journal of Aircraft

Volumn 39, Issue 5, 2002, Pages 759-775

  Leishman, J Gordon ^a   Bhagwat, Mahendra J ^a   Bagai, Ashish ^a  

^a UNIVERSITY OF MARYLAND   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ALGORITHMS; APPROXIMATION THEORY; BOUNDARY CONDITIONS; FINITE DIFFERENCE METHOD; FLIGHT DYNAMICS; HELICOPTER ROTORS; INTERPOLATION; NAVIER STOKES EQUATIONS; NUMERICAL METHODS; ORDINARY DIFFERENTIAL EQUATIONS; PARTIAL DIFFERENTIAL EQUATIONS;

FINITE DIFFERENCE APPROXIMATION; FREE-VORTEX FILAMENT METHODS; ROTOR WAKES;

WAKES;

EID: 0036757422     PISSN: 00218669     EISSN: 15333868     Source Type: Journal    
DOI: 10.2514/2.3022     Document Type: Article

References (82)

1. Leishman, J. G., Principles of Helicopter Aerodynamics, Cambridge Univ. Press, New York, 2000, Chap. 10.
2. Shrinivasan, G. R., and Baeder, J. D., "TURNS: A Free-Wake Euler Navier-Stokes Numerical Method for Helicopter Rotors," AIAA Journal, Vol. 31, No. 5, 1993, pp. 959-962.
3. Landgrebe, A. J., "New Directions in Rotorcraft Computational Aerodynamics Research in the U.S.," CP-552, Aerodynamics and Acoustics of Rotorcraft, AGARD, 1994.
4. McCroskey, W. J., "Vortex Wakes of Rotorcraft," AIAA Paper 95-0530, Jan. 1995.
5. Tang, L., and Baeder, J. D., "Improved Euler Simulation of Hovering Rotor Tip Vortices with Validation," Proceedings of the 55th Annual Forum of the American Helicopter Society International, May 1999.
6. Lewis, R. I., Vortex Element Methods for Fluid Dynamic Analysis of Engineering Systems, Cambridge Univ. Press, Cambridge, England, U.K., 1991.
7. Cottet, G.-H., and Koumoutsakos, P. D., Vortex Methods: Theory and Practice, Cambridge Univ. Press, Cambridge, England, U.K., 2000.
8. Crimi, P., "Theoretical Prediction of the Flow in the Wake of a Helicopter Rotor," Cornell Aeronautical Lab., Rept. BB-1994-5-1, Buffalo, NY, Sept. 1965.
9. Landgrebe, A. J., "The Wake Geometry of a Hovering Rotor and its Influence on Rotor Performance," Journal of the American Helicopter Society, Vol. 17, No. 4, 1972, pp. 2-15.
10. Kocurek, J. D., and Berkovitz, L. F., "Velocity Coupling: A New Concept for Hover and Axial Flow Wake Analysis and Design," CP-334, Prediction of Loads on Rotorcraft, AGARD, May 1982.
11. Beddoes, T. S., "A Wake Model for High Resolution Airloads," Proceedings of the 2nd International Conference on Basic Rotorcraft Research, Univ. of Maryland, College Park, MD, Feb. 1985.
12. Clark, D. R., and Leiper, A. C., "The Free Wake Analysis-A Method for Prediction of Helicopter Rotor Hovering Performance," Journal of the American Helicopter Society, Vol. 15, No. 1, 1970, pp. 3-11.
13. Scully, M. P., "A Method of Computing Helicopter Vortex Wake Distortion," Massachusetts Inst. of Technology, Rept. ASRL TR 138-1, Cambridge, MA, June 1967.
14. Scully, M. P., "Computation of Helicopter Rotor Wake Geometry and Its Influence on Rotor Harmonic Airloads," Massachusetts Institute of Technology, Rept. ASRL TR 178-1, Cambridge, MA, March 1975.
15. Sadler, S. G., "A Method for Predicting Helicopter Wake Geometry, Wake-Induced Inflow and Wake Effects on Blade Airloads," Proceedings of the 27th Annual American Helicopter Society Forum, May 1971.
16. Miller, R. H., "A Simplified Approach to the Free Wake Analysis of a Hovering Rotor," Vertica, Vol. 6, 1982, pp. 89-95.
17. Johnson, W., "A Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics, Part I: Analytical Development," NASA TM 81182, 1980.
18. Lezius, D. K., "Analytical Solution for Inviscid Vortex Rollup from Elliptically Loaded Wings," Journal of Aircraft, Vol. 12, No. 11, 1975, pp. 911-914.
19. Krasny, R., "Computation of Vortex Sheet Roll-Up in the Trefftz Plane," Journal of Fluid Mechanics, Vol. 184, 1987, pp. 123-155.
20. Rule, J. A., and Bliss, D. B., "Prediction of Viscous Trailing Vortex Structure from Basic Loading Parameters," AIAA Journal, Vol. 36, No. 2, 1998, pp. 208-218.
21. Bhagwat, M. J., and Leishman, J. G., "Correlation of Helicopter Tip Vortex Measurements," AIAA Journal, Vol. 38, No. 2, 2000, pp. 301-308.
22. Ananthan, S., Leishman, J. G., and Ramaswamy, M., "The Role of Filament Stretching in the Free-Vortex Modeling of Rotor Wakes," Proceedings of the American Helicopter Society 58th Annual National Forum, June 2002
23. Crouse, G. L., Jr., and Leishman, J. G., "A New Method for Improved Rotor Free Wake Convergence," 31st AIAA Aerospace Sciences Meeting, AIAA Paper 93-0872, Reno, NV, Jan. 1993.
24. Bagai, A., and Leishman, J. G., "Rotor Free-Wake Modeling Using a Relaxation Technique-Including Comparisons with Experimental Data," Journal of the American Helicopter Society, Vol. 40, No. 3, 1995, pp. 29-41.
25. Bhagwat, M., and Leishman, J. G., "Stability, Consistency and Convergence of Time Marching Free-Vortex Rotor Wake Algorithms," Journal of the American Helicopter Society, Vol. 46, No. 1, 2001, pp. 59-71.
26. Lee, D. J., and Na, S. U., "Predictions of Airloads and Wake Geometry for Slowly Starting Rotor Blades in Hovering Flight by Using Time Marching Free Vortex Blob Method," Proceedings of the 52nd Annual American Helicopter Society Forum, May 1996.
27. Bliss, D. B., and Miller, W. O., "Efficient Free Wake Calculations Using Analytical/Numerical Matching," Journal of the American Helicopter Society, Vol. 38, No. 2, 1993, pp. 53-60.
28. Johnson, W., "A General Free Wake Geometry Calculation For Wings and Rotors," Proceedings of the 51st Annual American Helicopter Society Forum, May 1995.
29. Bhagwat, M., and Leishman, J. G., "Accuracy of Straight-Line Segmentation Applied to Curvilinear Vortex Filaments," Journal of the American Helicopter Society, Vol. 46, No. 2, 2001, pp. 166-169.
30. Bliss, D. B., Quackenbush, T. R., and Bilanin, A. J., "A New Methodology for Helicopter Free-Wake Analyses," Proceedings of the 39th Annual Forum of the American Helicopter Society, May 1983.
31. Bliss, D. B., Dadone, L., and Wachspress, D. A., "Rotor Wake Modeling for High Speed Applications," Proceedings of the 43th Annual American Helicopter Society Forum, May 1987.
32. Quackenbush, T. R., Wachspress, D. A., and Boschitsch, A. H., "Computation of Rotor Aerodynamic Loads with a Constant Vorticity Contour Free Wake Model," AIAA Paper 91-3229, Sept. 1991.
33. Kaufmann, W., "Uber die Ausbreitung kreiszlindrischer Wirbel in zahen Flussigkeiten," Ingenieur Archiv, Vol. 31, No. 1, 1962, p. 1.
34. Ogawa, A., Vortex Flow, CRC Series on Fine Particle Science and Technology, CRC Press, Boca Raton, FL, 1993.
35. Miller, W. O., and Bliss, D. B., "Direct Periodic Solutions of Rotor Free Wake Calculations," Journal of the American Helicopter Society, Vol. 38, No. 2, 1993, pp. 53-60.
36. Bagai, A., and Leishman, J. G., "Rotor Free-Wake Modeling Using a Psuedoimplicit Relaxation Algorithm," Journal of Aircraft, Vol. 32, No. 6, 1995, pp. 1276-1285.
37. Bhagwat, M. J., and Leishman, J. G., "Stability Analysis of Rotor Wakes in Axial Flight," Journal of the American Helicopter Society, Vol. 45, No. 3, 2000, pp. 165-178.
38. Leishman, J. G., and Bagai, A., "Challenges in Understanding the Vortex Dynamics of Helicopter Rotor Wakes," AIAA Journal, Vol. 36, No. 7, 1998, pp. 1130-1140.
39. Quackenbush, T. R., Bliss, D. B., and Wachspress, D. A., "Computational Analysis of Hover Performance using a New Free Wake Method," 2nd International Conference on Rotorcraft Basis Research, Univ. of Maryland, College Park, Feb. 1988.
40. Miller, W. O., and Bliss, D. B., "Direct Periodic Solutions of Rotor Free Wake Calculations," Proceedings of the 46th Annual American Helicopter Society Forum, May 1990.
41. Bagai, A., and Leishman, J. G., "Free-Wake Analysis of Tandem, Tilt-Rotor and Coaxial Rotor Configurations," Journal of the American Helicopter Society, Vol. 41, No. 3, 1996, pp. 196-207.
42. Egolf, T. A., and Landgrebe, A. J., "Helicopter Rotor Wake Geometry and its Influence in Forward Flight, Vol. 1-Generalized Wake Geometry and Wake Effects in Rotor Airloads and Performance," NASA CR-3726, Oct. 1983.
43. Jain, R., and Conlisk, A. T., "Interaction of Tip-Vortices in the Wake of a Two-Bladed Rotor in Axial Flight," Journal of the American Helicopter Society, Vol. 45, No. 3, 2000, pp. 157-164.
44. Coyne, A. J., Bhagwat, M. J., and Leishman, J. G., "Investigation into the Rollup and Diffusion of Rotor Tip Vortices using Laser Doppler Velocimetry," Proceedings of the 53rd Annual American Helicopter Society Forum, May 1997.
45. Vatistas, G. H., "New Model for Intense Self-Similar Vortices," Journal of Propulsion and Power, Vol. 14, No. 4, 1998, pp. 462-469.
46. Vatistas, G. H., Kozel, V., and Mih, W. C., "A Simpler Model for Concentrated Vortices," Experiments in Fluids, Vol. 11, 1991, pp. 73-76.
47. Bagai, A., and Leishman, J. G., "Flow Visualization of Compressible Vortex Structures Using Density Gradient Techniques," Experiments in Fluids, Vol. 15, 1993, pp. 431-442.
48. Bhagwat, M. J., and Leishman, J. G., "On the Relationship between the Blade Lift and the Tip Vortex Characteristics," Proceedings of the 54th Annual American Helicopter Society Forum, May 1998.
49. Squire, H. B., "The Growth of a Vortex In Turbulent Flow," Aeronautical Quarterly, Vol. 16, Aug. 1965, pp. 302-306.
50. McAlister, K. W., Schuler, C. A., Branum, L., and Wu, J. C., "3-D Wake Measurements Near a Hovering Rotor for Determining Profile and Induced Drag," NASA TP-3577, 1995.
51. Mahalingam, R., and Komerath, N. M., "Measurements of the Near Wake of a Rotor in Forward Flight," Paper AIAA 98-0692, 1998.
52. Bhagwat, M. J., and Leishman, J. G., "Viscous Vortex Core Models for Free-Vortex Wake Calculations," Proceedings of the 58th Annual Forum of the American Helicopter Society International, June 2002.
53. Wood, D. H., and Mayer, C., "Two New Methods for Calculating Velocities Induced by a Constant Diameter Far Wake," Journal of Aircraft, Vol. 28, No. 8, 1991, pp. 526-531.
54. Radcliff, T. D., Burggraf, O. R., and Conlisk, A. T., "Axial Core Flow Effects on the Interaction of a Rotor-Tip Vortex with an Airframe," AIAA Paper 97-0658, Jan. 1997.
55. Clark, D. R., and Leiper, A. C., "The Free Wake Analysis: A Method for the Prediction of Helicopter Hovering Performance," Proceedings of the American Helicopter Society 25th Annual National Forum, May 1969.
56. Egolf, T. A., "Rotor Wake Modeling for High Speed Applications," Proceedings of the 44th Annual American Helicopter Society Forum, May 1988.
57. Brooks, T. F., Boyd, D. D., Burley, C. L., and Jolly, R. J., "Aeroacoustic Codes for Rotor Harmonic and BVI Noise-CAMRAD: Mod1/HIRES," AIAA Paper 96-1735, 1996.
58. Bagai, A., and Leishman, J. G., "Adaptive Grid Sequencing and Interpolation Schemes for Rotor Free-Wake Analyses," AIAA Journal, Vol. 36, No. 9, 1998, pp. 1593-1602.
59. Ghee, T. A., and Elliott, J. W., "The Wake of a Small-Scale Rotor Model in Forward Flight Using Flow Visualization," Journal of the American Helicopter Society, Vol. 40, No. 3, 1995, pp. 52-65.
60. Dingeldein, R. C., "Wind Tunnel Studies of the Performance of a Multirotor Configurations," NACA TN 3236, 1954.
61. Stepniewski, W. Z., "A Simplified Approach to the Aerodynamic Rotor Interference of Tandem Helicopter," Proceedings of the American Helicopter Society West Coast Region Meeting, Sept. 1955.
62. Sweet, G. E., "Hovering Measurements for Twin-Rotor Configurations with and Without Overlap," NASA TN D-534, 1960.
63. Stepniewski, W. Z., and Keys, C. N., Rotary-Wing Aerodynamics, Vol. 2, Dover, New York, 1984, Chap. 5.
64. Bagai, A., and Leishman, J. G., "Free-Wake Analysis of Tandem, Tilt-Rotor and Coaxial Rotor Configurations," Journal of the American Helicopter Society, Vol. 40, No. 3, 1995, pp. 196-207.
65. Griffiths, D. A., and Leishman, J. G., "A Study of Dual-Rotor Interference and Ground Effect Using a Free-Vortex Wake Model," Proceedings of the 58th Annual Forum and Technology Display of the American Helicopter Society International, June 2002.
66. Saberi, H. A., and Maisel, M. D., "A Free-Wake Rotor Analysis Including Ground Effect," Proceedings of the 43rd Annual American Helicopter Society Forum, May 1987.
67. Quackenbush, T. R., and Wachspress, D. A., "Enhancements to a New Free Wake Hover Analysis," NASA CR 177523, April 1989.
68. Itoga, N., Nagashima, T., Iboshi, N., Kawakami, S., Prasad, J. V. R., and Peters, D. A., "Numerical Analysis of Ground Effect for a Lifting Rotor Hovering at Close Proximity to Inclined Flat Surface," Proceedings of the American Helicopter Society Specialists' Meeting on Advanced Helicopter Technology and Disaster Relief, April 1999.
69. Sheridan, P. F., and Wiesner, W., "Aerodynamics of Helicopter Flight Near the Ground," Proceedings of the 33rd Annual Forum of the American Helicopter Society, May 1977.
70. Rosen, A., and Isser, A., "A New Model for Rotor Dynamics During Pitch and Roll of a Hovering Helicopter," Journal of the American Helicopter Society, Vol. 40, No. 3, 1995, pp. 17-28.
71. Keller, J. D., and Curtiss, H. C., "Modeling the Induced Velocity of a Maneuvering Helicopter," Proceedings of the 52nd Annual American Helicopter Society Forum, June 1996.
72. Barocela, E., Peters, D. A., Kothapalli, K. R., and Prasad, J. V. R., "The Effect of Wake Distortion on Rotor Inflow Gradients and Off-Axis Coupling," AIAA Flight Mechanics Conf., AIAA Paper 97-3579, July 1997.
73. Theodore, C., and Celi, R., "Flight Dynamic Simulation of Hingeless Rotor Helicopters Including a Maneuvering Free Wake Model," Proceedings of the 54th Annual American Helicopter Society Forum, May 1998.
74. Bagai, A., Leishman, J. G., and Park, J., "Aerodynamic Analysis of a Helicopter in Steady Maneuvering Flight Using a Free-Vortex Rotor Wake Model," Journal of the American Helicopter Society, Vol. 44, No. 2, 1999, pp. 109-120.
75. Drees, J. M., and Hendal, W. P., "The Field of Flow Through a Helicopter Rotor Obtained from Wind Tunnel Smoke Tests," Journal of Aircraft Engineering, Vol. 23, No. 266, 1951, pp. 107-111; also National Luchtvaart Laboratorium, Rept. A.1205, Feb. 1950.
76. Castles, W., Jr., and Gray, R. B., "Empirical Relation Between Induced Velocity, Thrust, and Rate of Descent of a Helicopter Rotor as Determined by Wind-Tunnel Tests on Four Model Rotors," NASA TN-2474, Oct. 1951.
77. Washizu, K., Azuma, A., Koo, J., and Oka, T., "Experiments on a Model Helicopter Rotor Operating in the Vortex Ring State," Journal of Aircraft, Vol. 3, No. 3, 1966, pp. 225-230.
78. Brinson, P., and Ellenrieder, T., "Experimental Investigation of Vortex Ring Condition," Proceedings of the 24st Annual European Rotorcraft Forum, Marseilles, France, Sept. 1998.
79. Wolkovitch, J., "Analytical Prediction of Vortex-Ring Boundaries for Helicopters in Steep Descents," Journal of the American Helicopter Society, Vol. 17, No. 3, 1972, pp. 13-19.
80. Heyson, H. H., "A Momentum Analysis of Helicopters and Autogyros in Inclined Descent, with Comments on Operational Restrictions," NASA TN D-7917, Oct. 1975.
81. Leishman, J. G., Bhagwat, M. J., and Ananthan, S., "The Vortex Ring State as a Spatially and Temporally Developing Wake Instability," Proceedings of the American Helicopter Society International Specialists Meeting on Aerodynamics, Acoustics and Test and Evaluation, Jan. 2002.
82. Leishman, J. G., Bhagwat, M. J., and Ananthan, S., "Free-Vortex Wake Predictions of the Vortex Ring State for Single-Rotor and Multi-Rotor Configurations," Proceedings of the 58th Annual Forum and Technology Display of the American Helicopter Society International, June 2002.