Rotorwash Operational Footprint Modeling

Abstract : Wind or rotorwash generated by rotors, ducts, or jets effect the operational suitability and utility of future Vertical Takeoff and Landing (VTOL) aircraft. As the aircraft s physical size, weight, and disk loading increases beyond the range of current systems, the risk increases that rotorwash operational impact(s) may compromise an aircraft s ability to satisfy the Warfighter's needs. Early definition of anticipated rotorwash conditions will permit an assessment of operational suitability and determine whether specific design changes are warranted and/or if acceptable operational tactics, techniques, and procedures can be established. This report documents the assessment process, environmental limits, rotorwash modeling, and output display supporting the rotorwash operational footprint model. These elements graphically combine to display the rotorwash operational impact assessment on the ground environment as contour plots or footprints. The tools developed are for the single main rotor helicopter, tandem helicopter, and tiltrotor configurations, but they can be extended to encompass additional configurations. The rotorwash operational footprint displays the effect of winds generated by rotor thrust on the surrounding environment. These footprints can be used to evaluate compliance with aircraft performance specifications, verify safe separation distances, or inform design trade studies.

[1]  Jon A. Peterka,et al.  Wind Uplift Model for Asphalt Shingles , 1999 .

[2]  Dylan Thomas,et al.  Numerical Prediction of Panel Dent Resistance Incorporating Panel Forming Strains , 2001 .

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

[4]  D. C. Dugan,et al.  The XV-15 tilt rotor research aircraft , 1980 .

[5]  R. Bellamy,et al.  THE PHYSICS AND BIOPHYSICS OF WOUND BALLISTICS , 2007 .

[6]  Richard P. White,et al.  STUDY OF THE VTOL DOWNWASH IMPINGEMENT PROBLEM , 1960 .

[7]  S. W. Ferguson,et al.  Empirical wake turbulence model of tiltrotor aircraft , 2005 .

[8]  Russell O Stanton.  Suitability of a Drag Sphere Anemometer for Measurement of VTOL Aircraft Downwash , 1970 .

[9]  V. Plank,et al.  Fog Modification by Use of Helicopters , 1970 .

[10]  Donald L. Loving.  Aerodynamic measurements made during Navy investigation of human tolerance to wind blasts , 1947 .

[11]  Richard E. Kuhn,et al.  Jet-Induced Effects: The Aerodynamics of Jet- And Fan-Powered V/STOL Aircraft in Hover and Transition , 2006 .

[12]  Grady W. Leese.  UH-1H Downwash Velocity Measurements , 1972 .

[13]  E. C. Poulton,et al.  The effects of wind on people; New criteria based on wind tunnel experiments , 1976 .

[14]  Wolfgang Rodi,et al.  The turbulent wall jet , 1979 .

[15]  D. Nixon,et al.  Unsteady three-dimensional simulations of a VTOL upwash fountain , 1986 .

[16]  H. Newhouse,et al.  VTOL DOWNWASH IMPINGEMENT STUDY , 1961 .

[17]  G W Leese.  HELICOPTER DOWNWASH BLAST EFFECTS STUDY , 1964 .

[18]  T. A. Wyatt,et al.  A model of wind-borne debris damage , 2002 .

[19]  Sarah Catherine Jordan.  An investigation of the slipstreams and wakes of trains and the associated effects on trackside people and objects , 2008 .

[20]  Emil Simiu,et al.  Tornado‐Borne Missile Speed Probabilities , 1983 .

[21]  R. E. Turner,et al.  Terrestrial environment (climatic) criteria guidelines for use in aerospace vehicle development , 1982 .

[22]  E. Kisielowski,et al.  INVESTIGATION OF THE DOWNWASH ENVIRONMENT GENERATED BY V/STOL AIRCRAFT OPERATING IN GROUND EFFECT , 1968 .

[23]  Samuel W. Ferguson.  Rotorwash Analysis Handbook. Volume 2. Appendixes , 1994 .

[24]  Wolfgang Rodi,et al.  The Turbulent Wall Jet Measurements and Modeling , 1983 .

[25]  H. H. Heyson.  Theoretical study of the effect of ground proximity on the induced efficiency of helicopter rotors , 1977 .

[27]  Peter Richards,et al.  Numerical calculation of the three-dimensional motion of wind-borne debris , 2008 .

[28]  David C. Burnham,et al.  Flight Test Investigation of Rotorcraft Wake Vortices in Forward Flight. , 1996 .

[29]  Richard L. Campbell,et al.  Flight-Test Experience Of A Helicopter Encountering An Airplane Trailing Vortex , 1976 .

[30]  R. W. Hale,et al.  EXPERIMENTAL STUDY OF PILOT VISIBILITY FROM A VTOL AIR/SEA CRAFT NEAR THE OCEAN SURFACE. , 1967 .

[31]  Nathan L. Wright,et al.  Assessment of Human Performance in a Simulated Rotorcraft Downwash Environment , 2007 .

[32]  Thomas C. O'Bryan,et al.  A BRIEF EVALUATION OF HELICOPTER WAKE AS A POTENTIAL OPERATIONAL HAZARD TO AIRCRAFT , 1962 .

[33]  Chris Letchford,et al.  Wind loads on rectangular signboards and hoardings , 1999 .

[34]  W. P. Schane.  EFFECTS OF DOWNWASH UPON MAN , 1967 .

[35]  Curtis L. Meyerhoff,et al.  Rotorwash Wind Sensor Evaluation , 1993 .

[36]  Paul A. Kremer,et al.  Effects of Missile Size and Glass Type on Impact Resistance of “Sacrificial Ply” Laminated Glass , 2002 .

[37]  P. Miller,et al.  Wall jets created by single and twin high pressure jet impingement , 1993, The Aeronautical Journal (1968).

[38]  Christopher Baker.  The debris flight equations , 2007 .

[39]  Jon A. Peterka,et al.  Comparison of pedestrian wind acceptability criteria , 1990 .

[40]  Bernard A. Niemeier,et al.  HAILSTONE RESPONSE OF BODY PANELS--REAL AND SIMULATED , 1978 .

[41]  Ning Lin.  Simulation of windborne debris trajectories , 2005 .

[42]  David H. Dickson,et al.  Helicopter Downwash Applied to Fog Clearing: A Status Summary , 1972 .

[43]  B. Cushman-Roisin,et al.  Cratering by a subsonic jet impinging on a bed of loose particles , 2006 .

[44]  Hongchao Zhu.  C-130 testings on low-rising buildings , 2006 .

[45]  R. E. Kuhn,et al.  Ground effects on v/stol and stol aircraft , 1985 .

[46]  Richard L. Campbell,et al.  Helicopter Response to an Airplane's Trailing Vortex , 1977 .

[47]  Ojars Skujins.  AN EXPERIMENTAL INVESTIGATION OF ROTOR FORCES AND FLOW FIELD IN THE VICINITY OF A STEP GROUND PLANE , 1970 .

[48]  P. G. Knott.  The Ground Environment Created by High Specific Thrust Vertical Land Aircraft , 1987 .

[49]  G. W. Stinnett,et al.  Hazard criteria for wake vortex encounters , 1975 .

[50]  O. Michaelsen.  A comparison of outflows from a helicopter, tilt wing and jet lift hovering aircraft , 1971 .

[51]  Daniel A. Wachspress,et al.  A Physics-Based Model of Rotorcraft Brownout for Flight Simulation Applications , 2006 .

[52]  Samuel W Ferguson.  Evaluation of Rotorwash Characteristics for Tiltrotor and Tiltwing Aircraft in Hovering Flight , 1990 .

[53]  R W James,et al.  Hurricane Related Window Glass Damage in Houston , 1984 .

[54]  Keith R Marsh.  RESEARCH ON VTOL WATER HOVER EFFECTS, INCLUDING THE EFFECTS OF WIND AND WAVES , 1968 .

[55]  Sarah Jordan,et al.  Evaluating and modelling the response of an individual to a sudden change in wind speed , 2008 .

[56]  C. W. Tillman,et al.  Aerodynamic Devices for Mitigation of Wind Damage Risk , 2008 .

[57]  John M. Cimbala,et al.  Experimental Investigation of a Jet Impinging on a Ground Plane in the Presence of a Cross Flow , 1987 .

[58]  P. Tanner.  Photogrammetric Characterization of a Brownout Cloud , 2011 .

[59]  Yukio Tamura,et al.  Tachikawa number: A proposal , 2006 .

[60]  Joel D Stitzel,et al.  Determination of significant parameters for eye injury risk from projectiles. , 2005, The Journal of trauma.

[61]  Hua-Chu Shih,et al.  Effects of Material Bending and Hardening on Dynamic Dent Resistance , 2003 .

[62]  Mirko Bolanovich,et al.  Experimental Downwash Velocity, Static Pressure, and Temperature Distributions in Ground Effect for a 75‐Foot Jet Driven Rotor , 1959 .

[63]  Kishor C. Mehta,et al.  Guide to the use of the wind load provisions of ASCE 7-02 , 1998 .

[64]  Shuzo Murakami,et al.  New criteria for wind effects on pedestrians , 1981 .

[65]  D. Migdal,et al.  Development of Theoretical Models for Jet-Induced Effects on V/STOL Aircraft , 1976 .

[66]  Shikha Jain.  Wind Effects on a Full-Scale Frame , 2002 .

[67]  Max F. Platzer,et al.  Prediction methods for jet V/STOL propulsion aerodynamics , 1976 .

[68]  Dennis W. Riddle,et al.  Flight measured downwash of QSRA , 1988 .

[69]  Samuel W Ferguson,et al.  Analysis and Recommendation of Separation Requirements for Rotorcraft Operation at Airports and Heliports , 1986 .

[70]  R. Wernicke.  Prediction of tilt rotor outwash , 1981 .

[71]  A. A. Perlmutter,et al.  DOWNWASH IMPINGEMENT DESIGN CRITERIA FOR VTOL AIRCRAFT , 1964 .

[72]  W. Wiesner,et al.  Tail Rotor Performance in Presence of Main Rotor, Ground, and Winds , 1974 .

[73]  G. Koch,et al.  Dynamic Denting of Autobody Panels , 1976 .

[74]  Robert D Smith,et al.  SAFE HELIPORTS THROUGH DESIGN AND PLANNING. A SUMMARY OF FAA RESEARCH AND DEVELOPMENT , 1994 .

[75]  Philip F Sheridan.  Interactional Aerodynamics of the Single Rotor Helicopter Configuration. Volume V. Harmonic Analyses of Hub Wake. , 1978 .

[76]  Xin Zhang,et al.  Ground effect aerodynamics , 2010 .

[77]  J. Leishman,et al.  Comparisons of Predicted Brownout Dust Clouds with Photogrammetry Measurements , 2011 .

[78]  Anjing Bi,et al.  Probabilistic assessment of wind loads on a full scale low rise building , 2006 .

[79]  John P. Dear,et al.  Impact damage processes in composite sheet and sandwich honeycomb materials , 2005 .

[80]  Wesley J. Cantwell,et al.  THE DAMAGE THRESHOLD OF LAMINATED GLASS STRUCTURES , 1998 .

[81]  Robert Lake,et al.  AV-8B-408 External Environment Outwash Flow Speed and Temperature Survey , 2000 .

[82]  Gloria K. Yamauchi,et al.  Investigating Tiltrotor Formation Flight via 1/48-Scale Wind Tunnel Experiment , 2006 .

[83]  W. A. Johnson,et al.  Analysis of vortex wake encounter upsets , 1974 .

[84]  Samuel W Ferguson.  Analysis of Rotorwash Effects in Helicopter Mishaps , 1991 .

[85]  V. Rossow.  Effect of ground and ceiling planes on shape of energized wakes , 1993 .

[86]  A comprehensive numerical model of wind-blown sand , 2009, 0901.0270.

[87]  J B Mckinley.  EVALUATING WIND FLOW AROUND BUILDINGS ON HELIPORT PLACEMENT , 1984 .

[88]  Rosanne M Weiss.  Analysis of Heliport Environmental Data; Intracoastal City , 1990 .

[89]  Robert D. Smith.  Heliport/Vertiport Design Deliberations 1997 - 2000 , 2001 .

[90]  Keyi Wang.  Flying debris behavior , 2003 .

[91]  John F. Ebersole.  Obscuration By Helicopter-Produced Snow Clouds , 1983 .

[92]  John G. Morrow,et al.  Analysis of Helicopter Environmental Data: Indianapolis Downtown Heliport, Wall Street Heliport. Volume 1. Summary , 1988 .

[93]  R. O. Schade,et al.  Ground interference effects , 1960 .

[94]  Coleman duP. Donaldson,et al.  A study of free jet impingement. Part 1. Mean properties of free and impinging jets , 1971, Journal of Fluid Mechanics.

[95]  Robert J. Hayduk,et al.  An Analytical Evaluation of the Denting of Airplane Surfaces by Hail , 1969 .

[96]  Samuel W. Ferguson,et al.  Rotorwash Computer Model (User's Guide) , 1991 .

[97]  M. J. Siclari,et al.  Stagnation Line and Upwash Formation of Two Impinging Jets , 1981 .

[98]  M. F. Shi,et al.  Static and Dynamic Dent Resistance Performance of Automotive Steel Body Panels , 1997 .

[99]  Sriram Sadagopan,et al.  Formability Characterization of a New Generation High Strength Steels , 2003 .

[100]  Randolph W. Spratt,et al.  Ground Environment Characterization of STOVL Fighter Propulsion Systems , 1990 .

[101]  W. J. Cosgrove,et al.  Empirically determined wind and scale effects on hot gas recirculation characteristics of jet V/STOL aircraft , 1969 .

[103]  William G. Hill,et al.  Investigation of VTOL Upwash Flows Formed by two Impinging Jets , 1977 .

[104]  Bharath Madapusi Govindarajan.  Evaluation of Particle Clustering Algorithms in the Prediction of Brownout Dust Clouds , 2011 .

[105]  Richard E Kuhn.  Height of Spray Produced by Vertical Takeoff and Landing (VTOL) Aircraft , 1979 .

[106]  Paul A. Kremer,et al.  Breakage Prediction of Laminated Glass Using the "Sacrificial Ply" Design Concept , 2004 .

[107]  M. J. Siclari,et al.  Fountain and Upwash Flowfields of Multijet Arrangements , 1978 .

[108]  William F Putman.  AN EXPERIMENTAL INVESTIGATION OF GROUND EFFECT ON A FOUR-PROPELLER TILT- WING V/STOL MODEL , 1968 .

[109]  P. Hrycak,et al.  Experimental flow characteristics of a single turbulent jet impinging on a flat plate , 1970 .

[110]  Xiaohong Hu.  Wind loading effects and equivalent static wind loading on low-rise buildings , 2006 .

[111]  John G. Morrow,et al.  ANALYSIS OF HELIPORT ENVIRONMENTAL DATA: INDIANAPOLIS DOWNTOWN HELIPORT, WALL STREET HELIPORT. VOLUME 3. INDIANAPOLIS DOWNTOWN HELIPORT DATA PLOTS , 1989 .

[112]  Scott A. Bole,et al.  Investigation of the Mechanics of Windborne Missile Impact on Window Glass , 1999 .

[113]  Chris P. Pantelides,et al.  Postbreakage Behavior of Heat Strengthened Laminated Glass under Wind Effects , 1993 .

[114]  J. E. Minor,et al.  Windborne debris and the building envelope , 1994 .

[115]  Ning Lin,et al.  Investigations of plate-type windborne debris—Part II: Computed trajectories , 2006 .

[116]  M. Finn,et al.  Static and dynamic denting of paint baked AA6111 panels: Comparison of finite element predictions and experiments , 2001 .

[117]  Navair,et al.  CH-47D Tandem Rotor Outwash Survey , 2011 .

[118]  J. D. Holmes,et al.  Trajectories of spheres in strong winds with application to wind-borne debris , 2004 .

[119]  C. C. Higgins,et al.  Dynamic pressure and thrust characteristics of cold jets discharging from several exhaust nozzles designed for vtol downwash suppression , 1964 .

[120]  Leishman,et al.  Investigation of Sediment Entrainment in Brownout Using High-Speed Particle Image Velocimetry , 2009 .

[121]  K. Breder,et al.  Loading rate effects during indentation and impact on glass with small spheres , 1993 .

[122]  David J. Hohler.  AN ANALYTICAL METHOD OF DETERMINING GENERAL DOWNWASH FLOW FIELD PARAMETERS FOR V/STOL AIRCRAFT , 1966 .

[123]  Ning Lin,et al.  Trajectories of Wind-Borne Debris in Horizontal Winds and Applications to Impact Testing , 2007 .

[124]  William G. Hill,et al.  Effect of nozzle spacing on ground interference forces for a two jet V/STOL aircraft , 1979 .

[125]  Grady W Leese,et al.  Helicopter Downwash Data , 1974 .

[126]  Zhongshan Zhao.  Wind flow characteristics and their effects on low-rise buildings , 1997 .

[127]  Daniel,et al.  A High Fidelity Brownout Model for Real-Time Flight Simulations and Trainers , 2009 .

[128]  David L. Kohlman.  Introduction to V/Stol Airplanes , 1981 .

[129]  M. Malin.  PREDICTION OF RADIALLY SPREADING TURBULENT JETS , 1988 .

[130]  Sujit Kumar Dalui,et al.  UNPLEASANT PEDESTRIAN WIND CONDITIONS AROUND BUILDINGS , 2006 .

[131]  R. H. Eustis,et al.  Plane Turbulent Wall Jet Flow Development and Friction Factor , 1963 .

[132]  J. Gordon Leishman,et al.  Understanding Brownout using Near-Wall Dual-Phase Flow Measurements , 2011 .

[133]  Edward J. Hanker,et al.  Parameters Affecting Helicopter Interactional Aerodynamics in Ground Effect , 1985 .

[134]  William G. Hill,et al.  Experimental Investigation of Multiple Jet Impingement Flows Applicable to VTOL Aircraft in Ground Effect. , 1975 .

[135]  M. Glauert.  The wall jet , 1956, Journal of Fluid Mechanics.

[136]  David T. Balch.  Experimental Study of Main Rotor/Tail Rotor/Airframe Interaction in Hover , 1983 .

[137]  John M. Cimbala,et al.  Experiments on the unsteadiness associated with a ground vortex , 1991 .

[138]  David J. Meuleman,et al.  Effect of Steel Strengthening Mechanisms on Dent Resistance of Automotive Body Panels , 1998 .

[139]  Todd R. Quackenbush,et al.  Rotorcraft Interactional Aerodynamics with Fast Vortex/Fast Panel Methods , 2003 .

[140]  L. D. Dzamba,et al.  Analysis of Helicopter Mishaps at Heliports, Airports and Unimproved Sites , 1991 .

[141]  Kerry Mitchell,et al.  Proceedings of the 1985 NASA Ames Research Center's Ground-Effects Workshop , 1987 .

[142]  Henry Liu,et al.  Wind Damage to Airport: Lessons Learned , 1988 .

[143]  Philip F. Sheridan,et al.  Investigation of Operational and Design Factors Resulting from Main Rotor and Tail Rotor Interactions. , 1984 .

[144]  Fuqiang Wu.  Full-scale study of conical vortices and their effects near roof corners , 2000 .

[145]  Gregory A. Kopp,et al.  Evaluation of Quasi-Steady Theory Applied to Windborne Flat Plates in Uniform Flow , 2009 .

[147]  Todd R. Quackenbush,et al.  Rotor design optimization using a free wake analysis , 1993 .

[149]  Boschitsch,et al.  First-Principles Free-Vortex Wake Analysis for Helicopters and Tiltrotors , 2003 .

[150]  D. Migdal,et al.  VTOL in ground effect flows for closely spaced jets. [to predict pressure and upwash forces on aircraft structures] , 1979 .

[151]  Ming F. Shi,et al.  An Evaluation of the Dynamic Dent Resistance of Automotive Steels , 1991 .

[152]  Peter J Unitt.  A Comprehensive Review of V/STOL Downwash Impingement with Emphasis on Wind Induced Recirculation. , 1969 .

[153]  Thomas J. Schmitt.  WIND-TUNNEL INVESTIGATION OF AIR LOADS ON HUMAN BEINGS , 1954 .

[154]  Joel T. Wareing.  Consideration of V/STOL Downwash and the Ground Environment , 1968 .

[155]  Stephen Sargent Visher,et al.  Climatic Atlas of the United States , 2000 .

[156]  J. A. DiCello,et al.  Design Criteria for the Dent Resistance of Auto Body Panels , 1974 .

[157]  Edward Hueske.  Practical Analysis and Reconstruction of Shooting Incidents , 2005 .

[158]  Cesar Farell,et al.  Aerodynamic Considerations for Rooftop Helideck Design , 1996 .

[159]  William J. Steptoe.  Estimated STOVL Strike Fighter Danger Area , 1992 .

[160]  Claire C. Gordon,et al.  2012 Anthropometric Survey of U.S. Army Personnel: Methods and Summary Statistics , 2014 .

[161]  Walter A. Johnson,et al.  A MODEL FOR HUMAN PILOT BEHAVIOR DURING WAKE VORTEX ENCOUNTER UPSETS , 1976 .

[162]  Robert K Souter,et al.  Summary of available hail literature and the effect of hail on aircraft in flight , 1952 .

[163]  Michael R. Dudley,et al.  Full-scale ground effects of twin impinging jets beneath a subsonic tactical V/STOL aircraft , 1986 .

[165]  William G. Hill,et al.  Ground Impingement of a Fan Jet Exhaust Plume , 1978 .

[166]  Comparison of wind load standards , 1995 .

[167]  M. D. Falarski,et al.  Ground effect hover characteristics of a large-scale twin tilt-nacelle V/STOL model , 1981 .

[168]  Samuel W. Ferguson,et al.  Wake Vortex Measurements Of The XV-15 Tiltrotor Using A Mobile Ground-Based LIDAR System , 2001 .

[169]  Grady W Leese,et al.  Materials evaluation for aircraft blast and helicopter downwash protection , 1975 .

[170]  Paul A. Kremer,et al.  Impact Resistance of Laminated Glass Using “Sacrificial Ply” Design Concept , 2000 .

[171]  Richard A. Behr,et al.  Damage probability in laminated glass subjected to low velocity small missile impacts , 1998 .

[172]  Samuel W Ferguson.  Rotorwash Analysis Handbook. Volume 1. Development and Analysis , 1994 .

[173]  B. Z. Jenkins,et al.  Rotor Downwash Velocities about the UH-1M Helicopter - Flight Test Measurements and Theoretical Calculations , 1975 .

[174]  C. A. Grotz.  Simulated VTOL Exhaust Impingement on Ground Surfaces , 1961 .

[175]  W. Lynn Beason,et al.  Designing for Windborne Missiles in Urban Areas , 1978 .

[176]  Ning Lin,et al.  Investigation of plate-type windborne debris. Part I. Experiments in wind tunnel and full scale , 2006 .

[177]  Joseph E. Minor.  Lessons Learned from Failures of the Building Envelope in Windstorms , 2005 .

[178]  John G. Morrow,et al.  ANALYSIS OF HELIPORT ENVIRONMENTAL DATA: INDIANAPOLIS DOWNTOWN HELIPORT WALL STREET HELIPORT. VOLUME 2. WALL STREET HELIPORT DATA PLOTS , 1989 .

[179]  J. C. Ball,et al.  XV-15 Shipboard Evaluation , 1983 .

[180]  H. H. Heyson.  Some wake-related operational limitations of rotorcraft , 1980 .

[181]  Gloria K. Yamauchi,et al.  Wind Tunnel Investigation of the Aerodynamic Interactions Between Helicopters and Tiltrotors in a Shipboard Environment , 2004 .

[182]  Boeing Vertol Co.,et al.  Improved Method Of Predicting Helicopter Control Response And Gust Sensitivity , 1979 .

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

[184]  R B Leahy,et al.  Structural Design Guidelines for Heliports. , 1984 .