Register now After registration you will be able to apply for this opportunity online.
This opportunity is not published. No applications will be accepted.
Cylindrical cavitation bubble dynamics between two flat plates
The goal of this project is to experimentally study cylindrical bubble dynamics. The student will quantify the effects of the test cell geometry on the bubble dynamics using laser-induced cavitation bubbles and high-speed imaging. Experiments will be conducted in water and other more complex fluids.
Keywords: cavitation, bubble dynamics, rheology
Lately, cavitation rheology has been increasingly attracting the attention of the scientific community. This experimental technology consists in observing cavitation bubble dynamics in a liquid and deducing its rheological properties by fitting the observed results to theory. This is convenient as spherical bubble dynamics generated in a laboratory agree very well with the spherical Rayleigh theory without any fitting parameters. By doing so, it allows researchers to probe extreme shear-rates that are not accessible to conventional rheometers.
However, in the case of opaque liquids, observations of such bubbles are not possible. This is where cylindrical cavitation bubbles may have a role to play. They are generally generated between two flat transparent boundaries and can be observed when they contact the plates. Although the dynamics are similar for these bubbles, the cylindrical Rayleigh model requires a fitted parameter to define the finite radius at which the fluid no longer “feels” the bubble dynamics. Furthermore, due to the friction at the boundaries, the interface between the gas-liquid phases tends to get incurved, resulting in non-perfectly cylindrical bubbles.
Lately, cavitation rheology has been increasingly attracting the attention of the scientific community. This experimental technology consists in observing cavitation bubble dynamics in a liquid and deducing its rheological properties by fitting the observed results to theory. This is convenient as spherical bubble dynamics generated in a laboratory agree very well with the spherical Rayleigh theory without any fitting parameters. By doing so, it allows researchers to probe extreme shear-rates that are not accessible to conventional rheometers.
However, in the case of opaque liquids, observations of such bubbles are not possible. This is where cylindrical cavitation bubbles may have a role to play. They are generally generated between two flat transparent boundaries and can be observed when they contact the plates. Although the dynamics are similar for these bubbles, the cylindrical Rayleigh model requires a fitted parameter to define the finite radius at which the fluid no longer “feels” the bubble dynamics. Furthermore, due to the friction at the boundaries, the interface between the gas-liquid phases tends to get incurved, resulting in non-perfectly cylindrical bubbles.
The goal of this project is to generate laser-induced cylindrical cavitation in a confined test chamber and to compare results in water with another fluid. Effects of fluid containment size will be analyzed. Their effect on the fitted parameter of the cylindrical Rayleigh theory will also be quantified. For this, a rheological test chamber will be designed and built. A setup capable of generating laser-induced cavitation bubbles will be put in place. The cylindrical bubble dynamics will be visualized using high-speed imaging. The experimental observations will be compared with theory, which we aim to improve for fluid characterization purposes.
The goal of this project is to generate laser-induced cylindrical cavitation in a confined test chamber and to compare results in water with another fluid. Effects of fluid containment size will be analyzed. Their effect on the fitted parameter of the cylindrical Rayleigh theory will also be quantified. For this, a rheological test chamber will be designed and built. A setup capable of generating laser-induced cavitation bubbles will be put in place. The cylindrical bubble dynamics will be visualized using high-speed imaging. The experimental observations will be compared with theory, which we aim to improve for fluid characterization purposes.
For additional information, the candidates can contact Guillaume Bokman via email (bokmang@ethz.ch)
For additional information, the candidates can contact Guillaume Bokman via email (bokmang@ethz.ch)