Visualization and measurements of shock waves in cavitating flow

Petkovšek, Martin (author), Hočevar, Marko (author), Dular, Matevž (author)

Upon cavitation cloud collapse an omnidirectional shock wave is emitted. It then travels through the flow field, causing a cascade of events resulting in erosion, noise, vibration and the cavitation shedding process. Despite that the accumulated data points evidently to the presence of the shock waves, the direct measurements hardly exist - and even then, they are very expensive and time consuming to perform. In the present paper, the possibility of detecting shock waves inside cavitating flow is shown. The methodology bases on using two conventional high speed cameras. With the first one cavitating flow from a distance is observed, determining the position of the wave, while the second camera with a microscopic lens enables a close-up view to determine the number and size change of air bubbles as a shock wave passed them. By calibration and reference measurements the amplitude of the shock waves was determined. This relatively simple approach enabled the first observation of shockwaves which occur at the cavitation cloud collapse (downstream of the attached cavity). Several examples of shock wave dynamics are shown and how they influence the general cavitation cloud behaviour. Shock wave front velocities and local pressure waves caused by cloud collapse were estimated from visualization, reaching values to more than 700 m/s and over 5 MPa respectively.

• Language: English
• Keywords: cavitation, shock waves, high speed video, cloud collapse
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2020
• Number of pages: 10 str.
• Numbering: Vol. 119, art. 110215
• PID: 20.500.12556/RUL-117685
• UDC: 532.528(045)
• ISSN on article: 0894-1777
• DOI: 10.1016/j.expthermflusci.2020.110215
• COBISS.SI-ID: 23172099
• Publication date in RUL: 21.07.2020

Record is a part of a journal

• Title: Experimental thermal and fluid science
• Shortened title: Exp. therm. fluid sci.
• Publisher: Elsevier
• ISSN: 0894-1777
• COBISS.SI-ID: 170523

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: kavitacija, udarni valovi, visokofrekvenčno snemanje, kolaps kavitacijskega oblaka