Hostname: page-component-cd9895bd7-fscjk Total loading time: 0 Render date: 2024-12-22T11:14:32.299Z Has data issue: false hasContentIssue false
  • English
  • Français

Impinging jets in cross-flow

Published online by Cambridge University Press:  04 July 2016

K. Knowles ,
D. Bray ,
P. J. Bailey  and
P. Curtis
K. Knowles
Affiliation:
Aeromechanical Systems Group Royal Military College of Science
D. Bray
Affiliation:
Aeromechanical Systems Group Royal Military College of Science
P. J. Bailey
Affiliation:
Logico Systems Ltd East Horsley
P. Curtis
Affiliation:
Aerodynamics DepartmentBritish Aerospace Military Aircraft LtdKingston-upon-Thames
Get access Rights & Permissions [Opens in a new window]

Abstract

The flow-fields associated with single and twin jets impinging in cross-flows have been studied. Parameters which affect the position of the ground vortex have been investigated: cross-flow-to-nozzle velocity ratio, cross-flow boundary layer thickness, nozzle height, nozzle pressure ratio, vector angle and nozzle splay with both fixed and moving ground planes. Results show that the ground vortex moves away from the nozzle centre-line as the ratio of cross-flow velocity to nozzle exit velocity is decreased; the rate of change of position, however, depends on other parameters (including the precise definition of nozzle exit velocity). Increasing nozzle height above the ground appears to cause little consistent variation in vortex position for a single jet but a marked forward movement of ground sheet separation point in the case of twin jets. For all cases there is an increase in penetration with increasing nozzle pressure ratio up to choking, with the subsequent behaviour dependent on the definition of nozzle equivalent velocity and cross-flow velocity ratio. The effect of the moving ground plane is to reduce vortex penetration significantly; this suggests that a moving ground plane simulation (or moving model) is essential when testing design configurations in ground effect in wind-tunnels. It is also shown that rig design can produce a blockage effect which moves the ground vortex significantly and can change other apparent parametric effects. Self-similarity laws are proposed for the ground vortex and the wall jet.

Type
Research Article
Information
The Aeronautical Journal , Volume 96 , Issue 952 , February 1992 , pp. 47 - 56
Copyright
Copyright © Royal Aeronautical Society 1992 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Abbott, W. A. Studies of Flow Fields Created by Vertical and Inclined Jets When Stationary or Moving Over a Horizontal Surface. ARC CP No. 911, October 1964.Google Scholar
2. Colin, P. E. and Olivari, D. The Impingement of a Circular Jet Normal to a Flat Surface With and Without Cross-Flow, European Research Office, AD 688-953, January 1969.Google Scholar
3. Webber, H. A. and Gay, A. VTOL Reingestion Model Testing of Fountain Control and Wind Effects, AIAA Paper No. 75-1217, AIAA/SAE 11th Propulsion Conf., September/October 1975.Google Scholar
4. Schwantes, E. The Recirculation Flow Pattern of a VTOL Lifting Engine, NASA TT F-14912, June 1973.Google Scholar
5. Stewart, V. R., Kuhn, R. E. and Walters, M. M.Characteristics of the Ground Vortex Developed by Various V/STOL Jets at Forward Speed, AIAA Paper No. 83-2494, AIAA Aircraft Design, Systems and Technology Meeting, Ft. Worth, TX, October 1983.Google Scholar
6. Cimbala, J. M., Stinebring, D. R., Treaster, A. L. and Billet, M. L. Experimental Investigation of a Jet Impinging on a Ground Plane in the Presence of a Cross-Flow, App. Res. Lab., Penn. State Univ., Contractor's Rept. to NADC, February 1987.Google Scholar
7. Bray, D. and Knowles, K. Normal Impinging Jet in Crossflow - a Parametric Investigation, AIAA Paper No. 89-2957, AIAA/ ASME/SAE/ASEE 25th Joint Propulsion Conf., Monterey, CA, July 1989.Google Scholar
8. Green, L. Private Communication, British Aerospace pic, November 1988.Google Scholar
9. Stott, M. R. Private Communication, British Aerospace pic, November 1988.Google Scholar
10. Ing, D. N. and Bailey, P. J. Private Communication, Logico Systems Ltd., June 1989.Google Scholar
11. Knowles, K. and Bray, D. Unpublished work, RMCS, 1990.Google Scholar
12. Stratford, B. S. The calculation of the discharge coefficient of profiled choked nozzles and the optimum profile for absolute air flow measurement, Aeronaut J, April 1964, 68.Google Scholar
13. Knowles, K. and Carpenter, P. W. A study of the time dependant method for calculating transonic flows in convergent nozzles, in: Numerical Methods In Laminar and Turbulent Flow, ed. Taylor, C. et al, pp 1455–1464. Pineridge Press, Swansea, 1985.Google Scholar
14. Verhoff, A. The 2-D Turbulent Wall Jet With and Without an External Stream, Rept. 626, Princeton Univ., 1963.Google Scholar
15. Ing, D. N. Effects of Nozzle Pressure on Ground Jet Entrainment, British Aerospace pic Rpt No. BAe-KAD-R-RES-3109, June 1985.Google Scholar
16. McGuirk, J. J. Private Communication, Imperial College, London, Mech. Eng. Dept., 1989.Google Scholar
17. Barata, J. M. M., Durao, D. F. G. and McGuirk, J. J. Numerical study of single impinging jets through a crossflow, J Aircraft, November 1989, 26 (11), pp 1002–1008.Google Scholar
18. Donaldson, C. P., du and Snedeker, R. S. A study of free jet impingement, Part 1, mean properties of free and impinging jets, / Fluid Mech, 1971, 45 (2), pp 281–319.Google Scholar
19. Tidball, I. C. V/STOL Aerodynamics - Development of Experimental Facilities, RMCS 42 degree course Aero. Eng. project rept., May 1990.Google Scholar
20. Knowles, K. and Bray, D. High Mach number impinging jets in cross-flow - comparison of computation with experiment, in: Numerical Methods in Laminar and Turbulent Flow vol. 6, ed. Taylor, C. et al, pp 1389–1398. Pineridge Press, Swansea, 1989.Google Scholar
21. Bray, D. and Knowles, K. Numerical Modelling of Impinging Jets in Cross-Flow, AIAA Paper No. 90-2246, AIAA/ASME/ SAE/ASEE 26th Joint Propulsion Conf., Orlando, Florida, 16- 18 July, 1990.Google Scholar