Hostname: page-component-848d4c4894-sjtt6 Total loading time: 0 Render date: 2024-06-29T16:30:03.606Z Has data issue: false hasContentIssue false
  • English
  • Français

Measurements in subsonic and supersonic free jets using a laser velocimeter

Published online by Cambridge University Press:  19 April 2006

Jark C. Lau ,
Philip J. Morris  and
Michael J. Fisher
Jark C. Lau
Affiliation:
Lockheed-Georgia Company, Marietta, Georgia
Philip J. Morris
Affiliation:
Lockheed-Georgia Company, Marietta, Georgia
Michael J. Fisher
Affiliation:
Institute of Sound and Vibration Research, University of Southampton, England
Get access Rights & Permissions [Opens in a new window]

Abstract

Velocity measurements in a 51 mm diameter turbulent jet are presented. The measurement programme is conducted in two parts. The first part is devoted to the validation of laser velocimeter (LV) data. This consists of comparative measurements with the LV and a hot-wire anemometer. The second part consists of a survey of the jet flow field at Mach 0·28, 0·90, and 1·37 under ambient temperature conditions. Radial and centre-line distributions of the axial and radial, mean and fluctuating velocities are obtained. The distributions indicate a decrease in the spreading rate of the mixing layer with increasing Mach number and a corresponding lengthening of the potential core. The results further indicate that these two parameters vary with the square of the jet Mach number. Radial distributions collapse when plotted in terms of ση*, where σ = 10.7/(1 - 0.273 MJ2) and η* = (r − r0·5)/x. This is true for distributions in planes located as far downstream as two potential core lengths. The collapsed data of mean velocity can be approximated by a Görtler error function profile: \[ U/U_J = 0.5[1-{\rm erf}(\sigma\eta^{*})]. \] Centre-line distributions at various Mach numbers also collapse if plotted in terms of x/xc, xc being the potential core length. A general equation for the collapsed data of mean velocity is given by: U/UJ = 1 - exp{1.35/(1 - x/xc)}, for the range of Mach numbers 0·3-1·4, where xc = 4.2 + 1.1 MJ2.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 93 , Issue 1 , 12 July 1979 , pp. 1 - 27
Copyright
© 1979 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

Barnett, D. O. & Giel, T. V. 1976 Arnold Engineering Development Center Report no. AEDCTR-76–36, Arnold Air Force Base.
Berman, N. S. 1972 N.A.S.A. CR-124254.
Birch, S. F. & Eggers, J. M. 1972 N.A.S.A. Conf. Proc. on Free Turbulent Shear Flows, vol. 1, N.A.S.A. SP-321, pp. 11–40.
Bradshaw, P., Ferris, D. H. & Johnson, R. H. 1964 J. Fluid Mech. 19, 591–624.
Brown, G. L. & Roshko, A. 1974 J. Fluid Mech. 64, 775–816.
Carey, B. B. 1954 Ph.D. thesis, University of Maryland.
Champagne, F. H. & Sleicher, C. A. 1967 J. Fluid Mech. 28, 177–182.
Davies, P. O. A. L. 1966 A.I.A.A. J. 4, 1971–1978.
Görtler, H. 1942 Z. angew. Math. Mech. 22, 244–254.
Halleen, R. M. 1964 A literature review on subsonic free turbulent shear flow. AFOSRTN-5444, U.S.A.F. (available from DDC as AD606 756).
Jerome, F. E., Guitton, D. E. & Patel, R. P. 1971 Aero. Quart. 23, 119.
Kleinstein, G. 1964 J. Spacecraft 1, 403–408.
Knott, P. & Mossey, P. 1975 Air Force Aero Propulsion Lab. TR-76–68, vol. II, pp. 390–416.
Kolpin, M. A. 1964 J. Fluid Mech. 18, 529–548.
Korst, H. H. & Chow, W. L. 1962 University of Illinois, Urbana, Mechanical Eng. TN 393–2.
Lau, J. C. 1971 Ph.D. thesis, University of Southampton.
Lau, J. C. 1979 To be published in Proc. Roy. Soc.
Lau, J. C. & Fisher, M. J. 1975 J. Fluid Mech. 67, 299–337.
Laufer, J. 1974 University of Southern California, Los Angeles, Rep. USCAE 125.
Liepmann, H. & Laufer, J. 1947 N.A.C.A. Tech. Note 1257.
Mclaughlin, D. K. & Tiederman, W. G. 1973 Phys. Fluids 16, 2082–2088.
Melling, A. 1971 Imperial Coll. Sci. & Techn. Rep. ET/TN/B/7.
Mollo-Christensen, E., Kolpin, M. A. & Martuccelli, J. R. 1964 J. Fluid Mech. 18, 285–301.
Morris, P. J. 1976 A.I.A.A. J. 14, 1468–1475.
Nagamatsu, H. T., Sheer, R. E. & Horvay, G. 1969 N.A.S.A. Conf. Washington, D.C., N.A.S.A. SP-207.
Perry, A. E. & Morrison, G. L. 1971 J. Fluid Mech. 47, 765–777.
Samuel, A. E. & Perry, A. E. 1974 Proc. 5th Australasian Conf. Hydraul. Fluid Mech., Christchurch, N.Z., vol. 1, pp. 368–375.
Smith, D. M. & Meadows, D. M. 1974 Proc. 2nd Int. Workshop Laser Velocimetry, vol. 1, pp. 27–44.
Tutu, N. K. & Chevray, R. 1975 J. Fluid Mech. 71, 785–800.
Whiffen, M. C. 1975 Proc. Minnesota Symp. Laser Anemometry, pp. 589–590.
Whiffen, M. C., Lau, J. C. & Smith, D. M. 1978 Proc. 3rd Int. Workshop Laser Velocimeter. Purdue University.
Whiffen, M. C. & Meadows, D. M. 1974 Proc. 2nd Int. Workshop Laser Velocimetry, vol. 1, pp. 1–12.
Witze, P. O. 1974 A.I.A.A. J. 12, 417–418.