DIMPLE GENERATOR OF VORTEX STRUCTURES

  • A. V. Voskobijnyk Institute of hydromechanics NASU, Kyiv, Ukraine
  • V. M. Turick NTUU “Igor Sikorsky Kyiv Polytechnic Institute”, Kyiv, Ukraine
  • O. A. Voskoboinyk Institute of hydromechanics NASU, Kyiv, Ukraine
  • V. A. Voskoboinick Institute of hydromechanics NASU, Kyiv, Ukraine
Keywords: hemispherical dimple, visualization, velocity and pressure fluctuations, vortex structures, correlation, spectrum

Abstract

The paper presents the results of experimental studies of the space-time characteristics of the velocity and pressure field inside a hemispherical dimple on a flat surface. The features of the formation and development of vortex structures generated inside the dimple, as well as their interaction with the streamlined surface of the dimple and the boundary layer were established. Integral, spectral and correlation characteristics of the field of velocity, dynamic and wall pressure fluctuations were obtained. The velocities and directions of transfer of large-scale vortex structures and small-scale vortices inside the dimple were determined. The frequencies of rotations and ejections of large-scale vortices, the frequencies of oscillations of the vortex flow inside the dimple and self-oscillations of the vortex structures of the shear layer, their subharmonics and harmonics of higher orders were established.

References

Leontiev A.I., Kiselev N.A., Vinogradov Yu.A., et al. Experimental investigation of heat transfer and drag on surfaces coated with dimples of different shape. International Journal of Thermal Sciences. 2017. Vol. 118. P. 152–167.

Isaev S.A., Leontiev A.I., Baranov P.A., Usachov A.E. Bifurcation of vortex turbulent flow and intensification of heat transfer in a hollow. Doklady Physics. 2000. Vol. 45, № 8. P. 389–391. https://doi.org/10.1134/1.1310729

Voskoboinick V.A., Grinchenko V.T., Makarenkov A.P. Correlation characteristics of a wall pressure fluctuation field in a turbulent boundary layer induced by a longitudinal flow along a flexible extended cylinder. International Journal of Fluid Mechanics Research. 2003. Vol. 30, № 6. P. 644–650.

Voskoboinick V.A., Voskoboinick A.A., Turick V.N., Voskoboinick A.V. Space and time characteristics of the velocity and pressure fields of the fluid flow inside a hemispherical dimple generator of vortices. J. Eng. Physics and Thermophysics. 2020. Vol. 93, № 5. P. 1205–1220. https://doi.org/10.1007/s10891-020-02223-3

Voskoboinick V., Kornev N., Turnow J. Study of near wall coherent flow structures on dimpled surfaces using unsteady pressure measurements. Flow Turbulence Com-bust. 2013. Vol. 90, № 4. P. 709–722. https://doi.org/10.1007/s10494-012-9433-9

Voskoboinick V.A., Turick V.N., Voskoboinyk O.A. et al. Influence of the Deep Spherical Dimple on the Pressure Field under the Turbulent Boundary Layer. Advances in Computer Science for Engineering and Education. ICCSEEA 2018. Ad-vances in Intelligent Systems and Computing. 2019. Vol 754. P. 23–32. https://doi.org/10.1007/978-3-319-91008-6_3

Terekhov V.I., Kalinina S.V., Mshvidobadze Yu.M. Heat Transfer Coefficient and Aerodynamic Resistance on a Surface with a Single Dimple. Journal of Enhanced Heat Transfer. 1997. Vol. 4, № 4. P. 131–145.

Voskoboinick V., Voskoboinick A., Voskoboinyk O., Turick V. Dimple generators of longitudinal vortex structures. Theory, Applications and Numerical Methods. IntechOpen: London, 2019. P. 1–12. https://doi.org/10.5772/intechopen.83518

Published
2021-07-21