### Session AJ: Bubbles I: Cavitation

8:00 AM–9:57 AM, Sunday, November 22, 2009
Room: 101I

Chair: Roger Arndt, University of Minnesota

Abstract ID: BAPS.2009.DFD.AJ.8

### Abstract: AJ.00008 : Cavitation induced by high speed impact of a solid surface on a liquid jet

9:31 AM–9:44 AM

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#### Authors:

Mohamed Farhat
(Ecole Polyechnique Federale de Lausanne)

Marc Tinguely
(Ecole Polyechnique Federale de Lausanne)

Mathieu Rouvinez
(Ecole Polyechnique Federale de Lausanne)

A solid surface may suffer from severe erosion if it impacts a liquid jet at high speed. The physics behind the erosion process remains unclear. In the present study, we have investigated the impact of a gun bullet on a laminar water jet with the help of a high speed camera. The bullet has a flat front and 11 mm diameter, which is half of jet diameter. The impact speed was varied between 200 and 500 ms$^{-1}$. Immediately after the impact, a systematic shock wave and high speed jetting were observed. As the compression waves reflect on the jet boundary, a spectacular number of vapour cavities are generated within the jet. Depending on the bullet velocity, these cavities may grow and collapse violently on the bullet surface with a risk of cavitation erosion. We strongly believe that this transient cavitation is the main cause of erosion observed in many industrial applications such as Pelton turbines.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2009.DFD.AJ.8