Investigation of the Development of Localized Disturbances in the Boundary Layer of a Flat Plate under Conditions of Moderate Degree of the Incoming Flow Turbulence behind the Surface Step
https://doi.org/10.25205/2541-9447-2021-16-1-65-80
Abstract
In a wind tunnel on a flat plate in a separated flow behind a rectangular step, the emergence and development of localized disturbances generated by low-frequency impulse deviations of the local surface section under conditions of low and moderate degrees of the incoming flow turbulence is studied. The results were obtained by hot-wire anemometry at low subsonic flow velocity. It was found that impulse deviations of the wall generate disturbances, which are socalled Streaky structures and wave packets of oscillations. The separation of the laminar boundary layer accelerates the growth of wave packets with subsequent turbulization of the near-wall flow. The specific features of the behavior of localized disturbances under conditions of moderate degree of free-stream turbulence are revealed.
Keywords
boundary layer,
flow separation,
transition to turbulence,
streaky structures,
wave packets,
moderate free-stream turbulence level
Supporting agencies: This work was partially carried out within the framework of the Program of Basic Scientific Research of State Academies of Sciences for 2013–2020 (project AAAA-A17-117030610128-8) and with state support for scientific research conducted under the guidance of leading scientists in Russian universities, agreement No. 075-15-2019-1923
About the Authors
I. A. Sadovsky
Khristianovich Institute of Theoretical and Applied Mechanics SB RAS
Russian Federation
Russian Federation
Ivan A. Sadovsky, Graduate Student, Senior Аssistant
Novosibirsk
M. M. Katasonov
Khristianovich Institute of Theoretical and Applied Mechanics SB RAS
Russian Federation
Russian Federation
Mikhail M. Katasonov, Doctor of Science (Physics and Mathematics), Leading Researcher
Novosibirsk
A. M. Pavlenko
Khristianovich Institute of Theoretical and Applied Mechanics SB RAS
Russian Federation
Russian Federation
Alexander M. Pavlenko, PhD, Senior Researcher
Novosibirsk
References
1. Landahl M. T. A note on an algebraic instability of in viscid parallel shear flows. J. Fluid Mech., 1980, vol. 98, p. 243−251.
2. Schmid P. J., Henningson D. S. Stability and Transition in Shear Flows. New York, Springer, 2001, 558 p.
3. Reshotko E. Transient growth: A factor in bypass transition. Phys. Fluids, 2001, vol. 13, no. 5, p. 1067–1075.
4. Chernorai V. G., Spiridonov A. N., Katasonov M. M., and Kozlov V. V. Generation of perturbations by a localized vibrator in the boundary layer of a nonswept wing. Journal of Applied Mechanics and Technical Physics, 2001, vol. 42, no. 5, p. 765–772.
5. Gorev V. N., Katasonov M. M. Origination and development of precursors on the fronts of streaky structures in the boundary layer on a nonswept wing. Thermophys. and Aeromech., 2004, vol. 11, no.3. p. 391–403.
6. Gorev V. N., Katasonov M. M., Kozlov V. V. Wave precursors on longitudinal structures on nonswept and swept wings. Doklady Physics, 2006, vol. 51, no. 9, p. 513–516.
7. Gorev V. N., Katasonov M. M., Kozlov V. V. Wave forerunners of streamwise structures in a sweptwing boundary layer. Fluid Dynamics, 2007, vol. 42, no. 5, p. 732–739.
8. Gorev V. N., Katasonov M. M., Scherbakov V. A. Experimental study of the origin and development of wave packets – forerunners of localized disturbances in two-dimensional and three-dimensional boundary layers. Siberian Journal of Physics, 2007, vol. 2, no. 4, p. 49–54.
9. Gorev V. N., Katasonov M. M., Kozlov V. V. Specific features of unsteady processes in the front regions of streaky structures in the boundary layer on a nonswept wing. Thermophysics and Aeromechanics, 2008, vol. 15, no. 3, p. 415–425.
10. Katasonov M. M., Motyrev P. A., Sboev D. S., Kozlov V. V., Evers Q. B. Development of the wave packets – forerunners at the straight wing boundary layer. Siberian Journal of Physics, 2012, vol. 7, no. 1, p. 28–37.
11. Schlichting H. Boundary-layer theory. New York, McGraw-Hill, 1955, 535 p.
12. Taghavi H., Wazzan A. R. Spatial stability of some Falkner-Skan profiles with reversed flow. Phys. Fluids, 1974, vol. 17, p. 2181−2183.
13. Nayfeh A. H., Ragab S. A., Al-Maaitah A. A. Effect of bulges on the stability of boundary layers. Phys. Fluids, 1988, vol. 31, no. 4, p. 796−806.
14. Michalke A. On the inviscid instability of wall-bounded velocity profiles close to separation. Z. Flugwiss. Weltraumforsch, 1990, vol. 14, p. 24−31.
15. Boiko A. V., Grek G. R., Dovgal A. V., Kozlov V. V. The Origin of Turbulence in Near-Wall Flows. Berlin, Springer, 2002, 267 p.
16. Grek G. R., Katasonov M. M., Kozlov V. V., Chernorai V. G. Modeling of "puff" structures in two-and three-dimensional boundary layers. Preprint no. 2, Novosibirsk, ITAM SB RAS, 1999, 26 p. (in Russ.)
Review
For citations:
Sadovsky I.A., Katasonov M.M., Pavlenko A.M. Investigation of the Development of Localized Disturbances in the Boundary Layer of a Flat Plate under Conditions of Moderate Degree of the Incoming Flow Turbulence behind the Surface Step. SIBERIAN JOURNAL OF PHYSICS. 2021;16(1):65-80. (In Russ.) https://doi.org/10.25205/2541-9447-2021-16-1-65-80
Views:
165
Email this article 