Experimental Fluid Dynamics
Cavitation, Biophysics, and Microfluidics

Asst Prof Claus-Dieter Ohl
School of Physical and Mathematical Sciences (SPMS)
Division of Physics and Applied Physics (PAP)
Nanyang Technological University (NTU), Singapore
Adjunct Prof with IHPC, A*STAR

Controlled cavitation in microfluidics

by Ed Zwaan, Severine Le Gac, Kinko Tsuji, and Claus-Dieter Ohl

The manuscript has bee published in Physical Review Letters. Here, we want to share some more information and movies on this work. For contact please email to me.

Bubble generation

A laser pulse focused from below in a microfluidic device (20 microns high, PDMS=polydimethylsiloxane) creates a pan-cake shaped and short lived bubble.

A picture of a microfluidic system

A picture of two identical systems on the rubber like substrate (PDMS). The holes are reservoirs for filling the lines.

Example of flow patterns: Radial flow

Vapor bubble dynamics in a large chamber with no nearby boundaries. The bubble essentially oscillates radially and the flow stops shortly after the bubble collapse. The movie is taken with 1 million frames/s, and the image width is 140microns.

Non-radial flow close to a boundary

The above example shows the flow close to single boundary. The bubble develops a liquid jetting flow towards the boundary. The bubble breaks up into two and creates two counter-rotating vortices. Please note that the flow doesn't stop after the bubble collapse but two persisting vortex rings are created. The movie is taken with 1 million frames/s, and the image width is 140microns.

In more complex geometries

In a channel (left) vorticity is transported the walls. In a triangular structure three jets are created and in a diamond a four 4-leafed clover is formed by four jets.