Cavitation Control using Mesoscale Surface Structuring in Marine Engineering and Hydraulic Systems
Final Report Abstract
We propose a passive cavitation control method to mitigate undesirable effects, such as structural vibration in the context of marine engineering and hydraulic systems. For this aim, we used different mesoscale surface structures, such as scalloped and sawtooth riblet structures, finned and roughness structures to control the cavitating flow around circular cylinders, and hydrofoils. We performed extensive experiments to investigate the effects of wall roughness and riblet structures on the dynamics of cavitation, cavitation instability and turbulence structures in the cross flow around and in the wake of a circular cylinder, and a hydrofoil at different cavitating regimes and various Reynolds numbers. We used high-speed cameras to visualize the cavitation structure and a Particle Image Velocimetry (PIV) method to measure the velocity fields. In addition, we measured the forces acting on the smooth cylinder and on the cylinders with different mesoscale surface structures, and we also performed an acoustic measurement, using a hydrophone located downstream of the cylinders. Finally, we numerically studied the dynamics of the cavitation flow around a benchmark hydrofoil with and without passive control methods and compared our numerical results with our experimental data. Our results showed that the mesoscale surface structures were very efficient in suppressing or mitigating cavitation. The cavitation-induced vibration exciting forces acting on the cylinders and hydrofoils with riblet structures were significantly reduced compared to the cases without cavitation control. Furthermore, a substantial reduction in the cavitation volume and the sound pressure level in the low- and middle-frequency ranges were observed for the hydrofoils with riblet structures. The large-scale cloud cavity on the hydrofoil with scalloped and sawtooth riblets was changed to a small-scale cavity, which modified the cavitation dynamics on the hydrofoil surface and controlled unsteady cloud cavitation.
Publications
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Experimental study of the influence of mesoscale surface structuring on single bubble dynamics. Ocean Engineering, 260, 111892.
Kadivar, Ebrahim; el Moctar, Ould & Sagar, Hemant J.
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Experimental investigation of the effects of cavitation control on the dynamics of cavitating flows around a circular cylinder. Ocean Engineering, 286, 115634.
Kadivar, Ebrahim; Lin, Yuxing & el Moctar, Ould
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Experimental Study of the Cavitation Effects on Hydrodynamic Behavior of a Circular Cylinder at Different Cavitation Regimes. Fluids, 8(6), 162.
Lin, Yuxing; Kadivar, Ebrahim & el Moctar, Ould
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Cavitation suppression and transformation of turbulence structure in the cross flow around a circular cylinder: Surface morphology and wettability effects. Ultrasonics Sonochemistry, 106, 106875.
Yu. Nichik, Mikhail; Ilyushin, Boris B.; Kadivar, Ebrahim; el Moctar, Ould & Pervunin, Konstantin S.
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Experimental investigation of partial and cloud cavitation control on a hydrofoil using bio-inspired riblets. Physics of Fluids, 36(5).
Lin, Yuxing; Kadivar, Ebrahim; el Moctar, Ould & Schellin, Thomas E.
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Experiments on Cavitation Control around a Cylinder Using Biomimetic Riblets. Journal of Marine Science and Engineering, 12(2), 293.
Kadivar, Ebrahim; Dawoodian, Mazyar; Lin, Yuxing & el Moctar, Ould
