Fluid Memory for Particles in 2D Brownian Motion

S. Wolf, and J. Czerwinska
University of Bern
Bern, Switzerland

Thermal fluctuations of microparticles are an important way of transport in biological cells. While the fluid properties, such as viscosity, cannot always be directly measured, the random path of a microparticle can be observed under microscope. The relation between the diffusion and the fluid viscosity is analytically well described for spherical particles.

Therefore, we have simulated and compared the effects of the shape (circle and triangle) on the flow induced by Brownian motion. We have setup a model that simulates the fluid dynamic around a particle. While the random walk of a particle has no memory, the induced vortices persist for a certain time. Hence, they can be used to measure the dissipation of information.