Open this publication in new window or tab >>Faculty of Engineering and Natural Science, Sabanci University, 34956 Tuzla, Istanbul, Turkey, Istanbul; Sabanci University Nanotechnology Research and Application Center, 34956 Tuzla, Istanbul, Turkey, Istanbul.
Advanced NEMS Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Medical Imaging.
School of Engineering, Computing and Mathematics, Oxford Brookes University, College Cl, Wheatley, Oxford OX33 1HX, United Kingdom, College Cl, Wheatley; Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom, Parks Road.
Faculty of Engineering and Natural Science, Sabanci University, 34956 Tuzla, Istanbul, Turkey, Istanbul; Sabanci University Nanotechnology Research and Application Center, 34956 Tuzla, Istanbul, Turkey, Istanbul; Center of Excellence for Functional Surfaces and Interfaces for Nano-Diagnostics (EFSUN), Sabanci University, Orhanli, 34956, Tuzla, Istanbul, Turkey, Orhanli, Tuzla.
Faculty of Engineering and Natural Science, Sabanci University, 34956 Tuzla, Istanbul, Turkey, Istanbul; Sabanci University Nanotechnology Research and Application Center, 34956 Tuzla, Istanbul, Turkey, Istanbul; School of Engineering, Computing and Mathematics, Oxford Brookes University, College Cl, Wheatley, Oxford OX33 1HX, United Kingdom, College Cl, Wheatley; Center of Excellence for Functional Surfaces and Interfaces for Nano-Diagnostics (EFSUN), Sabanci University, Orhanli, 34956, Tuzla, Istanbul, Turkey, Orhanli, Tuzla.
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2024 (English)In: Physics of fluids, ISSN 1070-6631, E-ISSN 1089-7666, Vol. 36, no 9, article id 093335Article in journal (Refereed) Published
Abstract [en]
This study introduces the first experimental analysis of shear cavitation in a microscale backward-facing step (BFS) configuration. It explores shear layer cavitation under various flow conditions in a microfluidic device with a depth of 60 μm and a step height of 400 μm. The BFS configuration, with its unique characteristics of upstream turbulence and post-reattachment pressure recovery, provides a controlled environment for studying shear-induced cavitation without the complexities of other microfluidic geometries. Experiments were conducted across four flow patterns: inception, developing, shedding, and intense shedding, by varying upstream pressure and the Reynolds number. The study highlights key differences between microscale and macroscale shear cavitation, such as the dominant role of surface forces on nuclei distribution, vapor formation, and distinct timescales for phenomena like shedding and shockwave propagation. It is hypothesized that vortex strength in the shear layer plays a significant role in cavity shedding during upstream shockwave propagation. Results indicate that increased pressure notably elevates the mean thickness, length, and intensity within the shear layer. Instantaneous data analysis identified two vortex modes (shedding and wake modes) at the reattachment zone, which significantly affect cavitation shedding frequency and downstream penetration. The wake mode, characterized by stronger and lower-frequency vortices, transports cavities deeper into the channel compared to the shedding mode. Additionally, vortex strength, proportional to the Reynolds number, affects condensation caused by shockwaves. The study confirms that nuclei concentration peaks in the latter half of the shear layer during cavitation inception, aligning with the peak void fraction region.
Place, publisher, year, edition, pages
AIP Publishing, 2024
National Category
Fluid Mechanics
Identifiers
urn:nbn:se:kth:diva-354897 (URN)10.1063/5.0225030 (DOI)001373369400014 ()2-s2.0-85205718930 (Scopus ID)
Note
QC 20241018
2024-10-162024-10-162025-02-09Bibliographically approved