Oxford Theoretical Physics
Condensed Matter Theory: Soft and Biological Matter
Julia Yeomans
Lecture Courses:
Research:
Vacancies:
Group Members:
- Rodrigo Ledesma Aguilar
- Miha Ravnik
- Lisa Moevius
- Ioannis Zacharoudiou
- Irwin Zaid
- Mitya Pushkin
- Henry Shum
Links:
- Oxford University
- Oxford Physics
- Theoretical Physics
- Condensed Matter Theory
- Theory of Soft and Biological Matter
- Oxford Argentine Tango Portal
Collaborators:
- Anna Balazs
- Issam Ali
- Davide Marenduzzo
- Enzo Orlandini
- Olivier Pierre-Louis
Back to current research interest
Low Reynolds number swimming
Microscopic organisms, such as bacteria and ciliated protozoa, swim in the low Reynolds number regime. This is analogous to humans trying to move in a very viscous liquid like treacle. Inertia is unimportant: once the swimmer ceases to move it stops instantly. The Stokes equations, which govern the zero Reynolds number limit, are invariant under time reversal and this means that to move at all the microswimmer must have a swimming stroke which is non-reciprocal in time.
We are using simple model swimmers to understand the hydrodynamics of swimming and the interactions that occur between organisms. One aim is to explore possible designs for fabricated microswimmers which could be used to carry payloads such as drugs. Another is to understand the statistics of the flow fields set up by swimming bacteria.
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Left: E-coli bacteria swimming.
Right: a man-made microswimmer [1]. The head is a red blood cell; the tail a string of magnetic colloids. [1] Dreyfus et al., Nature 437, 862 (2005). |
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Left: Swimming stroke of a model low Reynolds number swimmer Right: Trajectories of two swimmers for different initial relative positions: the paths deviate from linear because of hydrodynamic interactions between the swimmers. |
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Recent Publications:
1. Levy fluctuations and mixing in dilute suspensions of algae and bacteria, J. R. Soc. Interface 8, 1314 (2011). [arxiv]
2. Hydrodynamic synchronization at low Reynolds number, Soft Matter 7, 3074 (2011).3. Hydrodynamic interactions between two swimmers at low Reynolds number, Phys. Rev. Lett. 99, 228103 (2007) [arxiv]