Transport Phenomena - Delft University of Technology

Sorted by YearSorted by First Author

High-Speed Visualization and Piv Measurements of Cavitating Flows Around a Semi-Circular Leading-Edge Flat Plate and Naca0015 Hydrofoil

High-Speed Visualization and Piv Measurements of Cavitating Flows Around a Semi-Circular Leading-Edge Flat Plate and Naca0015 Hydrofoil, A. Yu. Kravtsova, D. M. Markovich, K. S. Pervunin, M. V. Timoshevskiy, and K. Hanjalic. International Journal of Multiphase Flow 2014, 60 , 119–134.

Download

[DOI] 

Abstract

Cavitating flows around a flat plate with semi-circular leading edge and a NACA0015 hydrofoil at attack angles ranging from 0 degrees to 9 degrees and with varying cavitation number are investigated using high-speed-imaging visualization (HIV) and particle-imaging velocimetry (Ply). Several known types of cavitation common to both foils, but also some different patterns, were observed. At small angles of incidence (less than 3 degrees), cavitation on the plate begins in the form of a streak array (bubble-band) whereas on the hydrofoil as traveling bubbles. For the regimes with developed cavitation on the NACA0015 hydrofoil, the scattered and discontinuous bubble streaks branch and grow but subsequently merge into bubble clouds forming a remarkably regular lattice pattern. Once the incidence angle increased to 9 degrees, the cavitation on the hydrofoil changed to a streaky pattern like that on the plate at small attack angles, whereas the regime on the plate showed no significant changes. The PIV method proved to be usable for measuring the instantaneous velocity also in the gas-vapor phase, albeit with reduced accuracy that was evaluated and accounted for on the basis of the effective (validation-surviving) number of imaging samples. The time-averaged velocity and turbulence moments show that the incipience of cavitation is governed by the development of the carrier-fluid flow around the foil leading edges, but the subsequent flow pattern depends strongly on the cavitation regime displaying markedly different distributions compared to the non-cavitating case. The main cavitation parameters: the maximum cavity length, the cloud cavity streamwise dimensions and the cloud shedding Strouhal number are analyzed and presented in function of the cavitation number and the attack angle in different scaling. The measurements confirm qualitatively the trends reported in the literature, but show also some quantitative differences, notably between the two foils considered. (C) 2013 Elsevier Ltd. All rights reserved.

BibTeX

@article{ ISI:000332821700010,
Author = {Kravtsova, A. Yu. and Markovich, D. M. and Pervunin, K. S. and Timoshevskiy, M. V. and Hanjalic, K.},
Title = {High-Speed Visualization and Piv Measurements of Cavitating Flows Around a Semi-Circular Leading-Edge Flat Plate and Naca0015 Hydrofoil},
Journal = {International Journal of Multiphase Flow},
Year = {2014},
Volume = {60},
Pages = {119-134},
Month = {},
Abstract = {Cavitating flows around a flat plate with semi-circular leading edge and a NACA0015 hydrofoil at attack angles ranging from 0 degrees to 9 degrees and with varying cavitation number are investigated using high-speed-imaging visualization (HIV) and particle-imaging velocimetry (Ply). Several known types of cavitation common to both foils, but also some different patterns, were observed. At small angles of incidence (less than 3 degrees), cavitation on the plate begins in the form of a streak array (bubble-band) whereas on the hydrofoil as traveling bubbles. For the regimes with developed cavitation on the NACA0015 hydrofoil, the scattered and discontinuous bubble streaks branch and grow but subsequently merge into bubble clouds forming a remarkably regular lattice pattern. Once the incidence angle increased to 9 degrees, the cavitation on the hydrofoil changed to a streaky pattern like that on the plate at small attack angles, whereas the regime on the plate showed no significant changes. The PIV method proved to be usable for measuring the instantaneous velocity also in the gas-vapor phase, albeit with reduced accuracy that was evaluated and accounted for on the basis of the effective (validation-surviving) number of imaging samples. The time-averaged velocity and turbulence moments show that the incipience of cavitation is governed by the development of the carrier-fluid flow around the foil leading edges, but the subsequent flow pattern depends strongly on the cavitation regime displaying markedly different distributions compared to the non-cavitating case. The main cavitation parameters: the maximum cavity length, the cloud cavity streamwise dimensions and the cloud shedding Strouhal number are analyzed and presented in function of the cavitation number and the attack angle in different scaling. The measurements confirm qualitatively the trends reported in the literature, but show also some quantitative differences, notably between the two foils considered. (C) 2013 Elsevier Ltd. All rights reserved.},
DOI = {10.1016/j.ijmultiphaseflow.2013.12.004},
ISSN = {0301-9322},
EISSN = {1879-3533},
ResearcherID-Numbers = {Markovich, Dmitriy/K-2247-2014},
Unique-ID = {ISI:000332821700010},
}

Generated by bib2html.pl (written by Patrick Riley ) on Fri Jul 28, 2017 13:53:01


Last modified: July 28 2017. © Delft University of Technology - TP group 2012