Register now After registration you will be able to apply for this opportunity online.
Bubbles in turbulence: PIV-PTV measurements of bubble and carrier-fluid velocity
Bubbles are entrained under the ocean surface when waves break at sea. While submerged, they enhance the transfer of gases between the atmosphere and ocean. When they rise back to the surface, they eventually burst, ejecting small aerosol particles into the atmosphere which impact mass, momentum, and energy transfer and serve as condensation nuclei for clouds. Understanding the bubbles' dynamics in the turbulent environment beneath the surface is important to modelling their eventual effects on these processes. This project will consider the dynamics of bubbles in a turbulent flow and will focus on the dynamics of small bubbles (whose rise velocities in quiescence are on the order of, or are smaller than, the typical turbulent velocities).
Particularly, questions to address include:
- How does the turbulence impact the bubbles’ average rising velocity?
- How do bubbles preferentially sample the turbulent flow?
- Which mechanisms of rise speed modification (non-linear drag, fast-tracking, loitering, etc.) are significant at different conditions?
The student will work with a microfluidic bubble injector placed inside the 2 m^3 water tank in Prof. Dr. Filippo Coletti’s laboratory, in which 128 water pumps are operated in a random sequence in order to produce a turbulent flow with nearly zero mean flow. Building off previous work carried out on a similar project project, the student will first optimize a microfluidic chip such that it reliably produces bubbles of a small, uniform size. Then, concurrent particle image velocimetry (PIV) and particle tracking velocimetry (PTV) will be carried out. PIV will yield the velocity field within a 2-D plane of the turbulence, while PTV will yield the 3-D trajectories of bubbles rising through the flow. Combining the two datasets, the student will use the co-located bubble and water velocity measurements to characterize the bubble behavior in turbulence.
The student will work with a microfluidic bubble injector placed inside the 2 m^3 water tank in Prof. Dr. Filippo Coletti’s laboratory, in which 128 water pumps are operated in a random sequence in order to produce a turbulent flow with nearly zero mean flow. Building off previous work carried out on a similar project project, the student will first optimize a microfluidic chip such that it reliably produces bubbles of a small, uniform size. Then, concurrent particle image velocimetry (PIV) and particle tracking velocimetry (PTV) will be carried out. PIV will yield the velocity field within a 2-D plane of the turbulence, while PTV will yield the 3-D trajectories of bubbles rising through the flow. Combining the two datasets, the student will use the co-located bubble and water velocity measurements to characterize the bubble behavior in turbulence.
- Optimize a microfluidic device (both the device itself and the housing which supports it) which will inject small bubbles
- Characterize the sizes and rate of production of bubbles produced by the injector using backlit high-speed imaging
- Set up and carry out a synchronized 2-D PIV, 3-D PTV experiment capturing bubble trajectories and the
- Develop Python code to analyze the bubbles’ dynamics in turbulence, focusing on their coupling to the surrounding instantaneous flow
- Optimize a microfluidic device (both the device itself and the housing which supports it) which will inject small bubbles - Characterize the sizes and rate of production of bubbles produced by the injector using backlit high-speed imaging - Set up and carry out a synchronized 2-D PIV, 3-D PTV experiment capturing bubble trajectories and the - Develop Python code to analyze the bubbles’ dynamics in turbulence, focusing on their coupling to the surrounding instantaneous flow
2025_Spring_bubble_project_advertisement.pdf
