In-flight flow visualization and pressure measurements at low speeds on the NASA F-18 high alpha research vehicle

Inflight results from surface and off surface flow visualizations and from extensive pressure distributions document the vortical flow on the leading edge extensions (LEXs) and forebody of the NASA F-18 high alpha research vehicle (HARV) for low speeds and angles of attack up to 50 deg. Surface flow visualization data, obtained using the emitted fluid technique, were used to define separation lines and laminar separation bubbles (LSB). Off surface flow visualization data, obtained by smoke injection, were used to document both the path of the vortex cores and the location of vortex core breakdown. The location of vortex core breakdown correlated well with the loss of suction pressure on the LEX and with the flow visualization results from ground facilities. Surface flow separation lines on the LEX and forebody corresponded well with the end of pressure recovery under the vortical flows. Correlation of the pressures with wind tunnel results show fair to good correlation.

[1]  Russell M. Cummings,et al.  Navier-Stokes predictions of the flowfield around the F-18 (HARV) wing and fuselage at large incidence , 1990 .

[2]  Robert M. Hall,et al.  Influence of Reynolds number on forebody side forces for 3.5-diameter tangent-ogive bodies , 1987 .

[3]  Daniel W. Banks,et al.  Surface flow visualization of separated flows on the forebody of an F-18 aircraft and wind-tunnel model , 1988 .

[4]  Daniel W. Banks,et al.  F-18 high alpha research vehicle surface pressures: Initial in-flight results and correlation with flow visualization and wind-tunnel data , 1990 .

[5]  D. Banks.  Wind-tunnel investigation of the forebody aerodynamics of a vortex-lift fighter configuration at high angles of attack , 1988 .

[6]  R. E. Curry,et al.  An airborne system for vortex flow visualization on the F-18 high-alpha research vehicle , 1988 .

[7]  Lysbeth A. Woolcott,et al.  Reports and Memoranda , 1974 .

[8]  John H. Del Frate,et al.  In-flight flow field analysis on the NASA F-18 high alpha research vehicle with comparisons to ground facility data , 1990 .

[9]  Farhad Ghaffari,et al.  Navier-Stokes solutions about the F/A-18 forebody-LEX configuration. [Leading Edge Extension] , 1989 .

[10]  Russell M. Cummings,et al.  Numerical simulation of high-incidence flow over the F-18 fuselage forebody , 1991 .

[11]  David M. Richwine,et al.  In-Flight Flow Visualization Characteristics of the NASA F-18 High Alpha Research Vehicle at High Angles of Attack , 1989 .

[12]  D. Fisher,et al.  Flight, Wind Tunnel, and Numerical Experiments with a Slender Cone at Incidence , 1982 .

[13]  E. C. Polhamus,et al.  A review of some Reynolds number effects related to bodies at high angles of attack , 1984 .

[14]  R. R. Meyer,et al.  Real-time pilot guidance system for improved flight-test maneuvers , 1983 .

[15]  Daniel W. Banks,et al.  Experimental investigation of the F/A-18 vortex flows at subsonic through transonic speeds , 1989 .

[16]  Stephen A. Whitmore,et al.  Preliminary results from a subsonic high angle-of-attack flush airdata sensing (HI-FADS) system: Design, calibration, and flight test evaluation , 1990 .

[17]  G. E. Erickson.  Water tunnel flow visualization and wind tunnel data analysis of the F/A-18. [leading edge extension vortex effects , 1982 .