Hostname: page-component-cd9895bd7-8ctnn Total loading time: 0 Render date: 2024-12-19T12:24:21.404Z Has data issue: false hasContentIssue false
  • English
  • Français

Time-depeiident and time-averaged turbulence structure near the nose of a wing-body junction

Published online by Cambridge University Press:  26 April 2006

William J. Devenport  and
Roger L. Simpson
William J. Devenport
Affiliation:
Department of Aerospace and Ocean Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
Roger L. Simpson
Affiliation:
Department of Aerospace and Ocean Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
Get access Rights & Permissions [Opens in a new window]

Abstract

The behaviour of a turbulent boundary layer on a flat surface as it encounters the nose of a cylindrical wing mounted normal to that surface is being investigated. A three-component laser anemometer has been developed to measure this highly turbulent three-dimensional flow. Measurements of all the non-zero mean-velocity and Reynolds-stress components have been made with this instrument in the plane of symmetry upstream of the wing. These data have been used to estimate some of the component terms of the turbulence kinetic energy equation. Histograms of velocity fluctuations and short-time cross-correlations between the laser anemometer and a hot-wire probe have also been measured in the plane of symmetry. In all, these results reveal much of the time-dependent and time-averaged turbulence structure of the flow here.

Separation occurs in the plane of symmetry because of the adverse pressure gradient imposed by the wing. In the time mean the resulting separated flow consists of two fairly distinct regions: a thin upstream region characterized by low mean backflow velocities and a relatively thick downstream region dominated by the intense recirculation of the mean junction vortex. In the upstream region the turbulence stresses develop in a manner qualitatively similar to those of a two-dimensional boundary layer separating in an adverse pressure gradient. In the vicinity of the junction vortex, though, the turbulence stresses are much greater and reach’ values many times larger than those normally observed in turbulent flows. These large stresses are associated with bimodal (double-peaked) histograms of velocity fluctuations produced by a velocity variation that is bistable. These observations are consistent with large-scale low-frequency unsteadiness of the instantaneous flow structure associated with the junction vortex. This unsteadiness seems to be produced by fluctuations in the momentum and vorticity of fluid from the outer part of the boundary layer which is recirculated as it impinges on the leading edge of the wing. Though we would expect these fluctuations to be produced by coherent structures in the boundary layer, frequencies of the large-scale unsteadiness are substantially lower than the passage frequency of such structures. It therefore seems that only a fraction of the turbulent structures are recirculated in this way.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 210 , January 1990 , pp. 23 - 55
Copyright
© 1990 Cambridge University Press

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

Abid, R. & Schmitt, R. 1986 Experimental study of a turbulent horseshoe vortex using a three-component laser velocimeter. AIAA-86-1069, AIAA/ASME 4th Fluid Mechanics, Plasma Dynamics and Lasers Conference, Georgia.
Ahn, S. 1986 Unsteady features of turbulent boundary layers. M.S. thesis, Virginia Polytechnic Institute and State University.
Baker, C. J. 1980 The turbulent horseshoe vortex. J. Wind Engng Indust. Aerodyn. 6, 9–23.Google Scholar
Belik, L. 1973 The secondary flow about circular cylinders mounted normal to a flat plate. Aero Q. 24, 47–54.Google Scholar
Dechow, R. & Felsch, K. O. 1977 Measurements of the mean velocity and of the Reynolds stress tensor in a three-dimensional turbulent boundary layer induced by a cylinder standing on a flat wall In Turbulent Shear Flows Symp., Pennsylvania State University, pp. 9.11–9.20.
Devenport, W. J. & Simpson, R. L. 1986 Some time-dependent features of turbulent appendage—body juncture flows. In 16th Symposium on Naval Hydrodynamics, July 14-18, Berkeley, CA (ed. W. C. Webster), pp. 312–335. National Academic Press.
Devenport, W. J. & Simpson, R. L. 1987 An experimental investigation of the flow past an idealized wing—body junction: data report. Dept. of Aerospace and Ocean Engineering, Virginia Polytechnic Institute and State University.
Devenport, W. J. & Simpson, R. L. 1988 LDV measurements in the flow past a wing—body junction. Fourth Intl Symp. on Applications of Laser Anemometry to Fluid Mechanics, Lisbon, Portugal.
Devenport, W. J. & Simpson, R. L. 1989 Time-dependent structure in wing—body junction flows. Turbulent Shear Flows 6. Springer.
Dickinson, S. C. 1986 An experimental investigation of appendage - flat plate junction flow. Vol. 1, Description. David Taylor Naval Ship Research and Development Center Rep. 86/051.Google Scholar
Durst, F., Melling, A. & Whitelaw, J. H. 1981 Principles and Practice of Laser Dopper Anemometry, Academic.
Echols, W. H. & Young, J. A. 1963 Studies of portable air-operated aerosol generators. NRL Rep. 5929.Google Scholar
Fiedler, H. & Head, M. R. 1966 Intermittency measurements in the turbulent boundary layer. J. Fluid Mech. 25, 719–735.Google Scholar
Harsh, M. D. 1985 Experimental investigation of a turbulent junction vortex. Ph.D. thesis, Virginia Polytechnic Institute and State University.
Hasan, M. A. Z., Casarella, M. J. & Rood, E. P. 1985 An experimental study of the flow and wall-pressure field around a wing—body junction. Shear Flow—Structure Interaction Phenomena (ed. A. Akay & M. Reischman), ASME NCA-1, pp. 89–95.
Kubendran, L. R., McMahon, J. & Hubbart, J. E. 1986 Turbulent flow around a wing—fuselage type juncture. AIAA J. 24, 1447–1452.Google Scholar
Mcmahon, H., Hubbart, J. & Kubendran, L. R. 1983 Mean velocities and Reynolds stresses upstream of a simulated wing—fuselage juncture. NASA CR 3695.Google Scholar
Mehta, R. D. 1984 Effect of wing nose shape on the flow in a wing/body junction. Aeronaut. J. 88, 456–460.Google Scholar
Moore, J. & Furlini, T. J. 1984 A horseshoe vortex in a duct. Trans. ASME J.: J. Engng Gas Turbines and Power 106, 668–676.Google Scholar
Rood, E. P. 1984 Experimental investigation of the turbulent large scale temporal flow in the wing—body junction. Ph.D. dissertation, The Catholic University of America
Sandborn, V. A. & Slogar, R. J. 1955 Study of the momentum distribution of turbulent boundary layers in adverse pressure gradients. NACA Tech. Note 3264.Google Scholar
Schlichting, H. 1968 Boundary-Layer Theory, 6th edn. pp. 511–512. McGraw-Hill.
Schubauer, G. F. & Klebanoff, P. S. 1950 Investigation of separation of the turbulent boundary layer. NACA Tech. Note 2133.Google Scholar
Shabaka, I. M. M. A. & Bradshaw, P. 1981 Turbulent flow measurements in an idealized wing—body junction. AIAA J. 19, 131–132.Google Scholar
Shiloh, K., Shivaprasad, B. J. & Simpson, R. L. 1981 The structure of a separating turbulent boundary layer. Part 3. Transverse velocity measurements. J. Fluid Mech. 113, 75–90.Google Scholar
Simpson, R. L. & Barr, P. W. 1974 Velocity measurements in a separating turbulent boundary layer using sampling spectrum analysis. Proc. Second Intl Workshop on Laser Velocimetry, II (ed. W. H. Stevenson & H. D. Thompson), pp. 15–43. Hemisphere.
Simpson, R. L. & Barr, P. W. 1975 Laser Doppler velocimeter signal processing using sampling spectrum analysis. Rev. Sci. Instrum. 46, 835–837.Google Scholar
Simpson, R. L. & Chew, Y.-T. 1979 Measurements in steady and unsteady separated turbulent boundary layers. Laser Velocimetry and Particle Sizing (ed. H. D. Thompson & W. H. Stevenson), pp. 179–196. Hemisphere.
Simpson, R. L., Chew, Y.-T. & Shivaprasad, B. G. 1980 Measurements of a separating turbulent boundary layer. Southern Methodist University Tech. Rep. SMU-4-PU.Google Scholar
Simpson, R. L., Chew, Y.-T. & Shivaprasad, B. G. 1981 The structure of a separating boundary layer. Part 1. Mean flow and Reynolds stresses. J. Fluid Mech. 113, 23–51.Google Scholar
Strickland, J. H. & Simpson, R. L. 1975 Bursting frequencies obtained from wall shear-stress fluctuations in a turbulent boundary layer. Phys. Fluids 18, 306–308.Google Scholar
Townsend, A. A. 1956 The Structure of Turbulent Shear Flow, pp. 26. Cambridge University Press.
Tree, I. 1986 Laser-Doppler velocimeter measurements in a turbulent junction vortex. Ph.D. thesis, Virginia Polytechnic Institute and State University.
Van Dyke, M. 1982 An Album of Fluid Motion. Stanford: Parabolic.