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A Parametric Study of Vane and Air-jet Vortex Generators

By Tim P. Bray

Abstract

An experimental parametric sturdy of vane and air-jet vortex generators in a turbulent boundary layer has been carried out. Experiments were carried out in two facilities, one with a free-stream velocity of 20 m/s and a boundary layer thickness (6) of 41.5 mm, and one in a high speed facility at free-stream Mach numbers of between 0.45 and 0.75 and a boundary layer thickness of 20 mm. Cross-stream data were measured at a number of downstream locations using a miniature five-hole pressure probe, such that local cross-stream velocity vectors could be derived. Streamwise vorticity was calculated using the velocity vector data. In the low speed study, vortex generator parameters were as follows: " Vane vortex generators: thin rectangular vanes with a vane aspect ratio of unity (2h/c = 1), free-stream velocity 20 m/s, incidence (cc = 10', 15', 18', 20'), height-to-boundary- layer- thickness-ratio (h/8 0.554,0.916,1.27,1.639), and strearnwise distance from the vortex generator (x/6 = 3.855,12.048,19.277,26.506). " Air-jet vortex generators: circular jet nozzles, free-stream velocity = 20 m/s, jet nozzle pitch and skew angles (cc, P= 30', 45', 60'), hole diameter-to-boundary-layer-thickness-ratio (D/5 = 0.098,0.193,0.289), jet-to-free-stream-velocity ratio (VR = 0.7,1.0,1.3,1.6,2.0), and strearnwise distance from the vortex generator (x/8 = 3.855,12.048,19.277,26.506). In the high-speed study, the vortex generator parameters were as follows: Vane vortex generators: thin rectangular vanes with an aspect ratio of unity, incidence ((X 1505 20'), he i ght-to- boundary- I ayer-th i ckne s s-rati o (h/8 = 0.75), strearnwise distance from the vortex generator (x/6 = 8.755 16.25,23.75), and free-stream Mach numbers of 0.45,0.6 and 0.75. Air-jet vortex generators: jet pitch ((x = 30', 45'), jet skew angle (P = 30', 45', 60'), hole diameter-to-boundary-layer-thickness-ratio (D/8 = 0.15,0.3), j et-to- free- strearn-ve loc ity ratio (VR = 1.6), and strearnwise distance from the vortex generator (x/6 = 8.75,16.25,23.75, 31.25), and free-stream Mach numbers of 0.50,0.6 and 0.75. Streamwise vorticity data from the experiment was used to generate prediction techniques that would allow the vorticity profiles, downstream of vane or air-jet vortex generators, to be predicted. Both techniques are based on the approximation of the experimental cross-stream vorticity data to Gaussian distributions of vorticity through the vortex centre. The techniques, which are empirically derived, are simple equations that give the peak vorticity and vortex radius based on the vortex generator parameters. Use of these descriptors allows the assembly of the Gaussian vorticity equation. Both techniques are compared with the experimental data set and were seen to produce peak vorticity results to within 12% and 20% (for the vanes and air-jets respectively), 15% for the radius of the vortex, and 15% and 20% in vortex circulation (for the vanes and air-jets respectively). The two simple prediction techniques allow good prediction of the vortex structure at extremely low computational effort

Publisher: Cranfield University
Year: 1998
OAI identifier: oai:dspace.lib.cranfield.ac.uk:1826/3569
Provided by: Cranfield CERES

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Citations

  1. (1972). 1. Experiments on a Turbulent Jet in a Cross-Flow. doi
  2. (1953). A Preliminary Investigation of Aerodynamic Characteristics of Small Inclined Air Outlets at Transonic Mach Numbers.
  3. (1960). A preliminary Note on a Modified Type of Air Jet for Boundary Layer Control.
  4. (1952). A Transonic Investigation of the Aerodynamic Characteristics of Plate- and Bell-Type Outlets for Auxiliary Air.
  5. (1990). Aerodynamics for Engineering Students. Third Edition. (Edward Arnold,
  6. (1988). An Experimental Investigation of the Use of Air Jet Vortex Generators to Control Shock Induced Boundary Layer Separation.
  7. (1992). Application of Computational Fluid Dynamics to the Study of Vortex Flow Control for the Management of Inlet Distortion. doi
  8. Aspects of Vortex Breakdown. doi
  9. (1983). Augustine's Laws and Major Systems Development Programs.
  10. Axial Flow in Trailing Line Vortices. doi
  11. (1998). Calibration of the DERA Bedford 4" Wind Tunnel. DERA/AS/HWA/WP97513/1.01,
  12. (1995). Chapter I of Fluid vortices, doi
  13. (1994). Computational Analysis of Co- and Contra- Rotating Streamwise Vortices in a Turbulent Boundary Layer. doi
  14. Corporate Development Advisor,
  15. (1952). Effects of Some Primary Variables of Rectangular Vortex Generators on the Static-Pressure Rise through a Short Diffuser.
  16. ESDU Transonic Data Memorandum 93024 - Vortex Generators for Control of Shock-Induced Separation, Part 1: Introduction and Aerodynamics.
  17. (1994). ESDU Transonic Data Memorandum 93025 - Vortex Generators for Control of Shock-Induced Separation, Part 2: Guide to Use of Vane Vortex Generator,
  18. (1987). Experiments about the Air Jet Vortex Generator.
  19. Exploring Corporate Strategy. Forth Edition,
  20. Flowfield Produced by Trailing Vortices in the Vicinity of the Ground. Technical note from: doi
  21. Forced Mixing in Boundary Layers. doi
  22. (1993). Inclined Air-Jets used as Vortex Generators to Suppress Shock-Induced Separation.
  23. (1992). Interaction of a Longitudinal Vortex with a Three-dimensional Turbulent Boundary Layer. doi
  24. (1995). Investigation of the Effects of a Vortex Generator Jet on a Turbulent Boundary Layer at High Subsonic Speed. MSc Thesis, College of Aeronautics,
  25. (1995). Inviscid Theory Applied to Vortex-Induced Mixing.
  26. Inviscid to Turbulent Transition of Trailing Vortices. doi
  27. (1972). Item Number 70015. Fluid Forces and Moments on Flat Plates.
  28. (1990). Jet Vortex Generators for Turbulent Flow Separation Control. doi
  29. (1992). Longitudinal Vortex Control - Techniques and Applications. The 32 nd Lanchester Lecture. Aeronautical Journal,
  30. Longitudinal Vortices Imbedded in Turbulent Boundary Layers. Part 1: Single Vortex. doi
  31. (1984). Means for Maintaining Attached Flow of a Flowing Medium.
  32. (1996). Measurement & Instrumentation Systems (Newnes,
  33. Measurements and Modelling of Flow Structure in the Wake of a Low Profile "Wishbone" Vortex Generator. doi
  34. (1995). Numerical Calculations for Air-Jet Vortex Generators in Turbulent Boundary Layers.
  35. (1963). Part 11 of Laminar Boundary Layers
  36. (1985). Preliminary Tests at Low Speeds on the Vorticity Produced by Air-Jet Vortex Generators. Research Memo Aero 85/01,
  37. (1997). Presentation on Advanced Compact Inlets,
  38. (1961). Shock Induced Separation and its Prevention by Design and Boundary Layer Control. doi
  39. Streamwise Vortex Production by Pitched and Skewed Jets in a Turbulent Boundary Layer. doi
  40. (1965). The Calculation of the Paths of Vortices from a System of Vortex Generators,
  41. (1947). The Elimination of Diffuser Separation by Vortex Generators.
  42. (1984). The Generation and Decay of Vorticity. Geophys. Fluid Dynamics, doi
  43. (1996). The Modelling of Symmetric Airfoil Vortex Generators. doi
  44. The Round Turbulent Jet in a Cross-Wind. doi
  45. The Structure and Development of Streamwise Vortex Arrays Embedded in a Turbulent Boundary Layer. doi
  46. Vortex Breakdown in Swirling Conical Flows. doi
  47. (1994). Vortex Flow Control for the Management of Intake Distortion -
  48. Vortex Generator Jets -A Means for Passive and Active Control of Boundary Layer Separation. doi
  49. (1954). Vortex Generators: their Design and their Effects on Turbulent Boundary Layers. Preliminary Report.
  50. (1986). Vortex Modelling of Single and Multiple Dilution Jet Mixing in a Cross Flow. doi
  51. Vortex/Boundary-Layer Interactions. doi
  52. (1974). Vorticity Associated with a Jet in a Cross Flow. doi
  53. (1989). Vorticity Generation and Transport. Keynote Paper KS-3, presented at the 10 th Australian Fluid Mechanics Conference,

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