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Elliptic jets. Part 1. Characteristics of unexcited and excited jets

  • Fazle Hussain (a1) and Hyder S. Husain (a1)
Abstract

This paper summarizes experimental studies of incompressible elliptic jets of different aspect ratios and initial conditions, and effects of excitations at selected frequencies and amplitudes. Elliptic jets are quite different from the extensively studied plane and circular jets - owing mainly to the fact that the azimuthal curvature variation of a vortical structure causes its non-uniform self-induction and hence complex three-dimensional deformation. Such deformation, combined with properly selected excitation can substantially alter entrainment and other turbulence phenomena, thus suggesting preference for the elliptic shape in many jet applications. The dominance of coherent structures in the jet far field is evident from the finding that switching over of the cross-section shape continues at least up to 100 equivalent diameters De. The locations and the number of switchovers are strongly dependent on the initial condition, on the aspect ratio, and, when excited, on the Strouhal number and the excitation level. We studied jets with constant exit momentum thickness θe, all around the perimeter, thus separating the effects of azimuthal variations of θe, (typical of elliptic jets) and of the shear-layer curvature. Also investigated are the instability characteristics, and enhanced entrainment caused by bifurcation as well as pairing of vortical structures. We discuss shear-layer and jet- column domains, and find the latter to be characterized by two modes : the preferred mode and the stable pairing mode - similar to those found in circular jets -both modes scaling on the newly-defined lengthscale De. The paper documents some time- average measurements and their comparison with those in circular and plane jets.

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Arms, R. J. & Hama, F. R. 1965 Phys. Fluids 8, 553.
Batchelor, G. K. 1967 An Introduction to Fluid Dynamics. Cambridge University Press.
Becker, H. A. & Massaro, T. A. 1968 J. Fluid Mech. 31, 435.
Bevilaqua, P. M. & Lykoudis, P. S. 1978 J. Fluid Mech. 89, 589.
Bradbury, L. J. S. 1965 J. Fluid Mech. 23, 31.
Bradshaw, P. 1966 J. Fluid Mech. 26, 225.
Bridges, J. E. 1984 Effects of initial condition on jet noise. MS thesis, University of Houston.
Bridges, J. E. & Hussain, A. K. M. F. 1987 J. Sound Vib. 117, 289.
Clark, J. A. & Kit, L. 1980 Trans. ASME I: J. Fluids Engng 102, 219.
Coles, D. E. 1962 Rand Corp. Rep. R-403-PR.
Corrsin, S. & Uberoi, M. S. 1950 NACA Rep. 988.
Crighton, D. G. 1973 J. Fluid Mech. 59, 665.
Crow, S. C. & Champagne, F. H. 1971 J. Fluid Mech. 48, 547.
Dhanak, M. R. & Bernardinis, B. 1981 J. Fluid Mech. 109, 189.
Everitt, K. W. & Robins, A. G. 1978 J. Fluid Mech. 88, 563.
Foss, J. F. 1977 Symp. Turb. Shear Flows, p. 11.3. Pennsylvania State University.
Foss, J. F. & Korschelt, J. F. 1983 J. Fluid Mech. 132, 79.
Gutmark, E. & Ho, C. M. 1985 AIAA J. 23, 354.
Gutmark, E. & Wygnanski, I. 1976 J. Fluid Mech. 73, 465.
Hayakawa, M. & Hussain, A. K. M. F. 1985 Turbulent Shear Flows, vol. 5, p. 4.33. Cornell University. (See also J. Fluid Mech. 180 (1987) 193.)
Hernan, M. A. & Jimenez, J. 1982 J. Fluid Mech. 119, 923.
Heskestad, G. 1965 J. Appl. Mech. 32, 721.
Ho, C. M. & Huerre, P. 1984 Ann. Rev. Fluid Mech. 16, 365.
Ho, C. M. & Gutmark, E. 1987 J. Fluid Mech. 179, 383.
Husain, H. S. 1984 An experimental investigation of unexcited and excited elliptic jets. PhD thesis, University of Houston.
Husain, H. S. & Hussain, A. K. M. F. 1983 Phys. Fluids 26, 2763.
Husain, Z. D. 1982 An experimental study of effects of initial and boundary conditions on near and fair fields of jet flows. PhD thesis, University of Houston.
Hussain, A. K. M. F. 1980 Lecture Notes in Physics, vol. 136, p. 252. Springer.
Hussain, A. K. M. F. 1983 Phys. Fluids 26, 2816.
Hussain, A. K. M. F. & Clark, R. 1977 Phys. Fluids 20, 1416.
Hussain, A. K. M. F. & Zaman, K. B. M. Q. 1985 J. Fluid Mech. 159, 85.
Kelly, R. E. 1967 J. Fluid Mech. 27, 667.
Kida, S., Takaoka, M. & Hussain, F. 1989 Phys. Fluids A 1, 630.
Krothapalli, A., Baganoff, D. & Karamcheti, K. 1981 J. Fluid Mech. 107, 201.
Laufer, J. 1983 J. Appl. Mech. 50, 1079.
Maxworthy, T. 1974 J. Fluid Mech. 64, 227.
Melander, M. V. & Hussain, F. 1988 NASA-Stanford CTR Rep. CTR-88, p. 257. (See also Phys. Fluids A 1 (1989) 633.)
Metcalfe, R., Hussain, A. K. M. F. Menon, S. & Hayakawa, M. 1987 Fifth Symp. Turbulent Shear Flow, vol. 5 (ed. F. Durst, B. E. Launder, F. W. Schmidt & J. H. Whitelaw), p. 110, Springer.
Monkewitz, P. A. 1988 J. Fluid Mech. 188, 223.
Morris, P. J. 1986 AIAA paper no. 86–1868, AIAA 10th Aeroacoustics Conf. July 9–11, Seattle, Washington.
Newman, B. G. 1967 Fluid Mechanics of Internal Flow (ed. G. Sorvan), p. 170. Elsevier.
Perry, A. E. & Morrison, G. L. 1971 J. Fluid Mech. 47, 765.
Rockwell, D. O. 1972 Trans. ASME E: J. Appl. Mech. 52, 263.
Sforza, P. M., Steiger, M. H. & Trentacoste, N. 1966 AIAA J. 4, 800.
Takaki, R. & Hussain, A. K. M. F. 1985 Turbulence Shear Flows, vol. 5, p. 3.19, Cornell University.
Tso, J. 1983 Coherent structures in a fully developed turbulent axisymmetric jet. PhD thesis, Johns Hopkins University. (See also J. Fluid Mech. 203 (1989) 425.)
Trentacoste, N. & Sforza, P. M. 1967 AIAA J. 5, 885.
Tsuchiya, Y., Horikoshi, C. & Sato, T. 1984 Turbulence Symp. p. 15.1, University of Missouri-Rolla.
Viets, H. & Sforza, P. M. 1972 Phys. Fluids 15, 230.
Winant, C. D. & Browand, F. K. 1974 J. Fluid Mech. 63, 237.
Wygnanski, I. & Fiedler, H. 1969 J. Fluid Mech. 38, 577.
Wygnanski, I., Champagne, F. & Marasli, B. 1986 J. Fluid Mech. 168, 31.
Zaman, K. B. M. Q. & Hussain, A. K. M. F. 1977 Turb. Shear Flows, p.11.23, Pennsylvania State University.
Zaman, K. B. M. Q. & Hussain, A. K. M. F. 1980 J. Fluid Mech. 101, 449.
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Journal of Fluid Mechanics
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