This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Jet Efflux Characteristics and their Influence on STOVL Aircraft Propulsion-Induced Effects
Annotation ability available
Sector:
Language:
English
Abstract
The direct relation between subcriticai jet efflux characteristics and propulsion induced changes in STOVL aircraft forces and moments is described in this paper. Subcriticai jets may have core lengths which range up to 6 diameters. The shorter core length jets tend to entrain ambient air more rapidly, inducing larger hover lift losses, and decay more rapidly, reducing adverse ground erosion. In transition flight, shorter core length jets show a decrease in the lift loss. Supercritical pressure ratio jets are also described; they tend to have a longer, higher pressure core. For both subcriticai and supercritical pressure ratio jets, the dynamic pressure decay is similar. In ground effect the supercritical jet induces an oscillating pressure distribution on the ground with reflected shocks and expansions which can increase ground erosion and at low ground heights cause non-monotonic lift loss variations. The limited experimental data available suggest that there is a need for a systematic investigation to more adequately relate supercritical jet decay to hover and transition flight induced aero/propulsion effects.
Recommended Content
Authors
Citation
Margason, R., Arledge, T., Wardwell, D., Hange, C. et al., "Jet Efflux Characteristics and their Influence on STOVL Aircraft Propulsion-Induced Effects," SAE Technical Paper 962250, 1996, https://doi.org/10.4271/962250.Also In
References
- Abramovich, G. N. “The Theory of Turbulent Jets,” The M.I.T. Press Cambridge 1963
- Wishart, D.P. “The Structure of a Heated Supersonic Jet Operating at Design and Off-Design Conditions” The Florida State University FAMU/FSU College of Engineering 1995
- Albertson, M.L. Dai, Y.B. Jensen, R.A. Rouse, H. “Diffusion of Submerged Jets,” Proceedings ASCE Dec. 1948 639 697
- Gentry, G.L. Margason, R.J. “Jet-Induced Lift Losses on VTOL Configurations Hovering In and Out of Ground Effect,” Feb. 1966
- Love, E.S. Grigsby, C.E. Lee, L.P. Woodling, M.J. “Experimental and Theoretical Studies of Axisymmetric Free Jets” 1959
- Shaw, C.S. Margason, R.J. “An Experimental Investigation of a Highly Underexpanded Sonic Jet Ejecting from a Flat Plate into a Subsonic Crossflow,” Dec. 1973
- Morris, P.J. “Turbulence Measurements in Subsonic and Supersonic Axisymmetric Jets in a Parallel Stream,” AIAA J 14 1976 1468 1475
- Johannesen, N.H. “Further Results on the Mixing of Free Axially-Symmetrical Jets of Mach Number 1.40,” 1959 1259 1285
- Warren, W.R. “An Analytical and Experimental Study of Compressible Free Jets,” Princeton University Princeton, NJ
- Troutt, T.R. McLaughlin, D. K. “Experiments on the Flow and Acoustic Properties of a Moderate-Reynolds-Number Supersonic Jet,” Journal of Fluid Mechanics 116 1982 123 156
- Eggers, J.M. “Velocity Profiles and Eddy Viscosity Distributions Downstream of a Mach 2.22 Nozzle Exhausting to Quiescent Air,” Acoustica 12 1962 257 277
- Pitkin, E.T. Glassman, I. “Experimental Mixing Profiles of a Mach 2.6 Free Jet,” Journal of the Aero/Space Sciences 25 1958 791 793
- Sami, S. Carmody, T Rouse, H. “Jet Diffusion in the Region of Flow Establishment,” J. Fluid Mech. 27 1967 231 252
- Kuhlman, J.M. Warcup, R.W. “Experimental Investigation of Jet-Induced Loads on a Flat Plate in Hover Out-of-Ground Effect,” Feb. 1979
- Levin, D.B. Wardwell, D.A. “Jet-Induced Effects on Small-Scale Hover Data in Ground Effect,” Journal of Aircraft 1996
- Kuhlman, J.M. Ousterhout, D.S. Warcup, R.W. “Experimental Investigation of Effect of Jet Decay Rate on Jet-Induced Pressures on a Flat Plate,” April 1978
- Kuhn, R.E. “An Experimental Method for Estimating Jet Induced Lift and Pitching Moment on STOVL Aircraft Out of Ground Effect,” Jan. 1996
- Kuhn, R.E. Stewart, V.R. “Lift and Pitching Moment Induced on Jet STOVL Aircraft in Ground Effect - Data Report,” June 1993
- Margason, R.J. “Propulsion-Induced Effects Caused Out-of-Ground Effect,” Dec. 1987
- Margason, R.J. “Fifty Years of Jet in Cross Flow Research,” April 1993