Velocity fields of vortex flow inside cross streamlined semi-cylindrical groove

Authors

DOI:

https://doi.org/10.20535/2521-1943.2019.86.172754

Keywords:

half-cylindrical groove, wind tunnel, boundary layer, hot-wire anemometer, vortex structure

Abstract

Background. Mechanisms of vortex structures generation in geometric inhomogeneities of streamlined surfaces as the basis for the development of low-cost control methods for hydromechanical and thermophysical characteristics of technical devices, aircraft and water vehicles.

Objective. Studying the features of the formation and interaction of vortex formations inside and near a cross streamlined semi-cylindrical groove on a flat surface, as well as the structure, kinematic and dynamic characteristics of the boundary layer using statistical analysis.

Methods. Experimental investiganions in a wind tunnel of the fields of averaged and fluctuation velocity components in  semi-cylindrical groove and its near wake on a hydraulically smooth flat surface by hot-wire measurements in the range of Reynolds numbers calculated along the plate length to the front edge of the recess Rex=U0x/n  from 3,8×104 up to  6,9×105.

Results. According to measurements in the mid-section of the groove of the fields of actual velocities, the probability density functions of the longitudinal velocity fluctuations, their coefficients of asymmetry and excess are obtained. The profiles of the averaged longitudinal velocity and the isotaches of the averaged and fluctuation velocity components inside the groove are constructed. The regions of formation of the reverse flow in the groove, the velocity field in the shear layer, and the features of its interaction with the stern wall of the groove were found. In the transition from the laminar flow regime of a groove with a low vortex formation intensity to a turbulent one, at first an intense flow is formed in the near-bottom region of the cavity, directed towards the direction of the main flow. That is the reason of generation of the large-scale vortex structures that are periodically ejected out from the groove. As a result of the transition, the intensities of the vortex motion and the circulation flow in the groove volume are significantly increased, and in the near wake there is a separation region with intense velocity fluctuations. It has been established that in the boundary layer above the groove, the law of the probability density distribution of the longitudinal velocity fluctuations is close to normal one, but in the recess to the Maxwellian one. With the deep of semi-cylindrical groove the asymmetry and excess coefficients increase.

Conclusions. A complex vortex flow that forms inside a half-cylindrical cavity leads to a change in the structure of the boundary layer above the plate. In the transition and turbulent flow regimes in the boundary layer on the plate, the features and regularities of both the generation of large-scale vortex structures inside the groove and their ejection out from the groove into the near wake are revealed. Thus, the conditions are established under which the transversely streamlined semi-cylindrical groove can serve as an effective generator of vortices, which can be used to control hydroaerodynamic drag and heat and mass transfer processes in structural elements of vehicles, power machines and apparatuses.

Author Biographies

V. N. Turick, Institute of Mechanical Engineering of National Technical University of Ukraine «Kyiv Polytechnic Institute»

PhD, professor

Applied hydroaeromechanics and mechatronic department

V. A. Voskoboinick, Інститут гідромеханіки НАН України

Відділ гідробіоніки і керування примежовим шаром, д.т.н., провідний науковий співробітник

O. A. Voskoboinick, Інститут гідромеханіки НАН України

Відділ технічної гідромеханіки, к.т.н., старший науковий співробітник

A. V. Voskoboinick, Інститут гідромеханіки НАН України

Відділ гідробіоніки і керування примежовим шаром, к.т.н., старший науковий співробітник

References

  1. Gortyshov, Yu.F., Popov, I.A., Olimpiev, V.V. and dr. (2009), Teplogidravlicheskaya effektivnost’ perspektivnykh sposobov intensifikatsii teplootdachy v kanalakh teploobmennogo oborudovaniya [Heat-hydraulic efficiency of perspective methods of intensification of heat emission in the channels of heat-exchange equipment], Tcentr innovatcionnykh tekhnologii, Kazan’, Russia.
  2. Liu J., Xie, G. and Simon, T.W. (2015), “Turbulent flow and heat transfer enhancement in rectangular channels with novel cylindrical grooves”, Int. J. Heat and Mass Transfer, vol. 81, pp. 563 – 577, https://doi.org/10.1016/j.ijheatmasstransfer.2014.10.021
  3. Voskoboinick, V.A. and Voskoboinick, A.V. (2014), “Coherent vortex structures inside the cross-streamlined oval dimple”, Science-Based Technologies, vol. 23, no. 3, pp. 352–358, https://doi.org/10.18372/2310-5461.23.7416
  4. Voskoboinick, V.A. and Voskoboinick, A.V. (2016), “Velocity field and vortex motion inside the semi-cylindrical trench”, Industrial heat engineering, vol. 38, no. 4, pp. 11 – 20.
  5. Тurick, V.N., Voskoboinick, V.A. and Voskoboinick, A.V. (2018), “Vortex motion inside cross streamlined trench”, Mechanics and Advanced Technologies, vol. 83, no. 2, pp. 64 – 71.
  6. Tay, C.M., Chew, Y.T., Khoo, B.C. and Zhao, J.B. (2014), “Development of flow structures over dimples”, Experimental Thermal and Fluid Science, vol. 52, pp. 278 – 287.
  7. Turick, V.N., Voskoboinick, V.A. and Voskoboinick, A.V. (2017), “Influence of the local cross-streamlined obstacles on a velocity and pressure fluctuations”, Naukovi visti NTUU “KPI”, no. 1, pp. 106 – 114.
  8. Blake, W.K. (1986), Mechanics of flow-induced sound and vibration: in 2 vol., Academic Press, NY, USA.
  9. Voskoboinick, V.A., Grinchenko, V.T. and Makarenkov, A.P. (2005), “Pseudo-sound behind an obstacle on a cylinder in axial flow”, Intern. J. Fluid Mech., vol. 32, no. 4, pp. 488 – 510.
  10. Vencel’, E.S. and Ovcharov, L.A. (2000), Teorija sluchainykh processov i eje inzhenernye prilozhenija [Theory of random processes and its engineering applications], Vyshch. schk., Moscow, Russia.
  11. Bendat, J. and Pirsol, A. (1989), Prikladnoi analiz sluchainykh dannykh, per. s angl. [Random Data], Mir, Moscow.
  12. Voskoboinick, V., Kornev, N. and Turnow, J. (2013), “Study of near wall coherent flow structures on dimpled surfaces using unsteady pressure measurements”, Flow Turbulence Combust., vol. 90, no. 4, pp. 709 – 722.
  13. Voskoboinick, V.A., Turick, V.N. and Voskoboinyk, O.A. and dr. (2019), “Influence of the Deep Spherical Dimple on the Pressure Field under the Turbulent Boundary Layer”, in Hu, Z., Petoukhov, S., Dychka, I., He, M. (ed.), Advances in Computer Science for Engineering and Education, ICCSEEA 2018. Advances in Intelligent Systems and Computing, Springer, Cham., vol. 754. pp. 23 – 32.
  14. Kamruzzaman, M., Djenidi, L., Antonia, R.A. and Talluru, K.M. (2015), “Scale-by-scale energy budget in a turbulent boundary layer over a rough wall”, Int. J. Heat and Fluid Flow, vol. 55, pp. 2 – 8.
  15. Terekhov, V.I., Kalinina, S.V. and Mschvidobadze, Yu.M. (1992), “Experimental research flow evolution inside channel with semispherical cavity”, Sib. Phys.-techn. J., no. 1, pp. 77 – 86.

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Published

2019-11-23

How to Cite

[1]
V. N. Turick, V. A. Voskoboinick, O. A. Voskoboinick, and A. V. Voskoboinick, “Velocity fields of vortex flow inside cross streamlined semi-cylindrical groove”, Mech. Adv. Technol., no. 2(86), pp. 84–92, Nov. 2019.

Issue

No. 2(86) (2019)

Section

Up-to-date machines and the technologies of mechanical engineering

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