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Energy separation in a vortex street

Published online by Cambridge University Press:  21 April 2006

M. Kurosaka ,
J. B. Gertz ,
J. E. Graham ,
J. R. Goodman ,
P. Sundaram ,
W. C. Riner ,
H. Kuroda  and
W. L. Hankey
M. Kurosaka
Affiliation:
Massachusetts Institute of Technology, Cambridge, MA 02139, USA Present address: The University of Tennessee Space Institute, Tullahoma, Tennessee 37388.
J. B. Gertz
Affiliation:
Massachusetts Institute of Technology, Cambridge, MA 02139, USA Present address: Pratt & Whitney Aircraft, Hartford, Connecticut 06108.
J. E. Graham
Affiliation:
Air Force Wright Aeronautical Laboratories, Wright Patterson Air Force Base OH 45433, USA
J. R. Goodman
Affiliation:
The University of Tennessee Space Institute, Tullahoma, TN 37388, USA
P. Sundaram
Affiliation:
The University of Tennessee Space Institute, Tullahoma, TN 37388, USA
W. C. Riner
Affiliation:
The University of Tennessee Space Institute, Tullahoma, TN 37388, USA Present address: Teledyne Brown Engineering, Huntsville, Alabama 35807.
H. Kuroda
Affiliation:
The University of Tennessee Space Institute, Tullahoma, TN 37388, USA Present address: Japan Defense Academy, Yokosuka, Japan.
W. L. Hankey
Affiliation:
The Wright State University, Dayton, OH 45433, USA
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Abstract

When a bluff body is placed in a crossflow, the total temperature in its wake can become substantially less than the incoming one, as manifested by the fact that the recovery factor R on its rearmost surface takes negative values at high subsonic flow: this is the phenomenon referred to here as the Eckert-Weise effect. Although a vortex street has been a suspected cause, the issue of whether this is so, and what the mechanism is, has remained unsettled. In this experimental and theoretical investigation, we first examine the cause of the Eckert-Weise effect by enhancing the vortex shedding through acoustic synchronization: resonance between the vortex shedding and transversely standing acoustic waves in a wind tunnel. At the lowest synchronization, where a ringing sound emanates from the wind tunnel, R at the rearmost section of the cylinder is found to become negative even at a Mach number of 0.2; the base pressure (Cpb) takes dips correspondingly, indicative of the intensification of the vortex street. At this lowest acoustic resonance, the decrease of R and Cpb, uniform along the span, agrees with the expectation based on the spanwise uniformity of the lowest standing wave. At the next acoustic resonance where the standing wave now varies along the span, the corresponding dips in R and Cpb, non-uniform along the span, reveals an interesting ‘strip-theory’-like behaviour of the vortex intensities in the vortex street. These results correlating the change in R with Cpb confirm that the Eckert-Weise effect is indeed caused by the vortex shedding, the mechanism of which is examined theoretically in the latter half of the paper.

A simple theoretical argument, bolstered by a full numerical simulation, shows that the time-varying static pressure field due to the vortex movement separates the instantaneous total temperature into hot and cold spots located around vortices; once time-averaged, however, the total temperature distribution conceals the presence of hot spots and takes the guise of a colder wake, the Eckert-Weise effect. Therefore the correct explanation of the Eckert-Weise effect, a time-averaged phenomenon, emerges only out of, and only as a superposition of, instantaneous total temperature separation around vortices. Such a separation is not confined to the outside of vortex cores; every vortex in its entirety becomes thermally separated. Nor is it limited to the far downstream equilibrium configuration of the Kármán vortex street but applies to the important near-wake vortices, and to any three-dimensional vortical structure as well. For low subsonic flows in particular, this dynamical explanation also leads to a similar separation of total pressure; these features may thus be potentially exploited as a general marker to identify and quantify vortices.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 178 , May 1987 , pp. 1 - 29
Copyright
© 1987 Cambridge University Press

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References

Ackeret, J. 1954 Mitteilungen aus dem Institute für Aerodynamik No. 21. ETH, Zürich.
Bearman, P. W. & Graham, J. M. R. 1980 J. Fluid Mech. 99, 225–245.
Berger, E. & Willie, R. 1972 Ann. Rev. Fluid Mech. 4, 313–340.
Bishop, R. E. D. & Hassan, A. Y. 1964 Proc. R. Soc. Lond. A277, 51–75.
Bloor, M. S. 1964 J. Fluid Mech. 19, 290–304.
Cantwell, B. & Coles, D. 1983 J. Fluid Mech. 136, 321–374.
Chakroun, W. M., Ng, W. F. & Kurosaka, M. 1987 Ann. Tech. Rep. (1986) for AFOSR-83-0049. U.S. Air Force Office of Scientific Research.
Chen, C. F. & Mangione, B. J. 1969 AIAA J. 7, 1211–1212.
Cumpsty, N. A. & Whitehead, D. S. 1971 J. Sound Vib. 18, 353–369.
Davies, M. E. 1976 J. Fluid Mech. 75, 209–231.
Davis, R. W. & Moore, E. F. 1982 J. Fluid Mech. 116, 475–506.
Dean, R. C. 1959 Trans. ASME 81, 24–28.
Eckert, E. R. G. 1984 Mech. Engng 106, 58–65.
Eckert, E. R. G. & Weise, W. 1943 Forschg. Ing. Wesen 13, 246–254.
Gertz, J. B. 1985 Unsteady design-point flow phenomena in transonic compressors. Ph.D. thesis, MIT.
Goldstein S. (ed.) 1965 Modern Developments in Fluid Dynamics, vol. II, p. 561. Dover.
Goldstein, R. J., Behbahani, A. I. & Heppelman, K. K. 1986 Intl J. Heat Mass Transfer 29, 1227–1235.
Griffin, O. M. & Ramberg, S. E. 1974 J. Fluid Mech. 66, 553–576.
Griffin, O. M. & Ramberg, S. E. 1975 J. Fluid Mech. 69, 721–728.
Hiramoto, M., Kaji, S., Okazaki, T. & Kishimoto, K. 1972 Trans. JSME 38, 1353–1361 (in Japanese).
Kirde, K. 1962 Ing. Arch. 31, 385–404.
Kurosaka, M. 1982 J. Fluid Mech. 124, 139–172.
Kurosaka, M. & Sundaram, P. 1986 Phys. Fluids 29, 3474–3477.
Lamb, H. 1932 Hydrodynamics, 6th edn, p. 225. Dover.
Liepmann, H. W. & Roshko, A. 1957 Elements of Gas Dynamics, p. 190. Wiley.
Maccormack, R. W. 1969 AIAA Paper 69–354.
Minchin, L. T. 1951 In Proc. of the General Discussion on Heat Transfer, Sept. 1951, p. 485. The Institution of Mechanical Engineers and the American Society of Mechanical Engineers.
Parker, R. 1966 J. Sound Vib. 4, 62–72.
Preston, J. H. 1961 Aero. Quart. 12, 343–360.
Roshko, A. 1955 J. Aero. Sci. 22, 124–132.
Ryan, L. F. 1951 Experiments in aerodynamic cooling. Ph.D. thesis, ETH, Zürich.
Saffman, P. G. & Schatzmann, J. C. 1982 J. Fluid Mech. 122, 467–486.
Schaefer, J. W. & Eskinazi, S. 1959 J. Fluid Mech. 6, 241–260.
Schultz-Grunow, F. 1960 Theory and Fundamental Research in Heat Transfer. In Proc. the Annual Meeting of ASME (ed. J. A. Clark), pp. 87–103. Pergamon.
Shang, J. S. 1982 AIAA Paper 82–0098.
Stansby, P. K. 1976 J. Fluid Mech. 74, 641–665.
Taneda, S. 1965 J. Phys. Soc. Japan 20, 1714–1721.
Taneda, S. & Honji, H. 1967 Rep. Res. Inst. for Appl. Mech., vol. 15, No. 50, pp. 83–92.
Thomann, H. 1959 FFA Report 84. Stockholm.
Toebes, G. H. 1969 Trans. ASME D. J. Basic Engng 91, 493–505.
Wu, C. H. 1953 Trans. ASME 75, 802.