Abstract
An experimental investigation was made of the initial-section flow of axisymmetric helium, air, and freon-12 jets in a parallel air flow for two different velocity profiles at the nozzle exit near the boundary of the jet. In one case, the velocity profile was determined by boundary layers on the nozzle walls; in the other case, it was produced artificially by means of a honeycomb of tubes of variable length. Measurements were made of the profiles of the mean and the pulsation velocity and the temperature. The flow was also photographed. The investigations showed that, depending on the initial conditions, the intensity of mixing of the jets in the initial section at Reynolds numbers Re ≥ 104 (calculated using the jet diameter) can change from the level determined by molecular diffusion to the level characteristic of developed turbulent flow. The flow structure in the annular mixing layer also depends strongly on the initial conditions. The observed ordered structures in the mixing layer are related to a section of development of perturbations near the nozzle. The ordered structures are strongly influenced by the effect on the jet of acoustic vibrations from an external source. When the initial velocity profile is produced by the honeycomb, the transition to developed turbulence may be due to the development of long-wavelength perturbations or to the development of small-scale turbulence generated by the flow over the end of the honeycomb.
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Literature cited
O. I. Navoznov and A. A. Pavel'ev, “Mixing of parallel gas jets”, Izv. Akad. Nauk SSSR, Energ. Transp., No. 2 (1968).
O. I. Navoznov and A. A. Pavel'ev, “Wake behind a plate formed by the coalescence of two flows of incompressible fluids with different densities,” Izv. Akad. Nauk SSSR, Energ. Transp., No. 6 (1969).
O. I. Navoznov and A. A. Pavel'ev, “On the transition to turbulence in wakes,” Izv. Akad. Nauk SSSR, Mekh. Zhidk. Gaza, No. 6 (1969).
O. I. Navoznov, A. A. Pavel'ev, and A. V. Yatsenko, “On the transition to turbulence in immersed jets and wakes,” Izv. Akad. Nauk SSSR, Mekh. Zhidk. Gaza, No. 4 (1972).
G. L. Brown and A. Roshko, “On density effects and large structure in turbulent mixing layers,” J. Fluid Mech.,64, No. 4 (1974).
V. M. Ievlev, Turbulent Motion of High-Temperature Continuous Media [in Russian], Nauka, Moscow (1975).
B. E. Launder and D. B. Spalding, Lectures on Mathematical Models of Turbulence, Academic Press, London-New York (1972).
A. A. Pavel'ev, “Development of lattice turbulence in a flow with constant velocity gradient,” Izv. Akad. Nauk SSSR, Mekh. Zhidk. Gaza, No. 1 (1974).
V. G. Lushchik, A. A. Pavel'ev, and A. E. Yakubenko, “Three-parameter model of shear turbulence,” Izv. Akad. Nauk SSSR, Mekh. Zhidk. Gaza, No. 3 (1978).
S. I. Bekritskaya, “Experimental investigation of small-scale turbulence in a shear flow” Izv. Akad. Nauk SSSR, Mekh. Zhidk. Gaza, No. 4 (1977).
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Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 4, pp. 18–24, July–August, 1980.
We thank V. M. levlev and K. I. Artamonov for assistance and for discussing the work.
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Navoznov, O.I., Pavel'ev, A.A. Influence of the initial conditions on axisymmetric jets in a parallel flow. Fluid Dyn 15, 488–493 (1980). https://doi.org/10.1007/BF01089604
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DOI: https://doi.org/10.1007/BF01089604