Biotechnology at low Reynolds numbers

Noisy swimming at low Reynolds numbers.

Small organisms (e.g., bacteria) and artificial microswimmers move due to a combination of active swimming and passive Brownian motion. Considering a simplified linear three-sphere swimmer, we study how the swimmer size regulates the interplay between self-driven and diffusive behavior at low Reynolds number. Starting from the Kirkwood-Smoluchowski equation and its corresponding Langevin equati...

Shear layer instability at low reynolds numbers

Optimal swimming at low Reynolds numbers.

Efficient swimming at low Reynolds numbers is a major concern of microbots. To compare the efficiencies of different swimmers we introduce the notion of "a swimming drag coefficient" which allows for the ranking of swimmers. We find the optimal swimmer within a certain class of two-dimensional swimmers using conformal mapping techniques.

Boundary Layer Trips on Airfoils at Low Reynolds Numbers

Three categories of boundary layer trips (single 2-D plain. multiple 2-D plain, and 3-D trips) were tested on the l\106-13-128, E374, and SD7037 airfoils over t he Reynolds numbers of 100,000 to 300,000. Flow visualization and drag data were acquired for a number of trip heights and locations. To facilitate comparisons between airfoils, t rips were located relative to untripped laminar separati...

7 Swimming , Pumping and Gliding at low Reynolds numbers

Simple, linear equations relate microscopic swimmers to the corresponding gliders and pumps. They have the following set of consequences: The swimming velocity of free swimmers can be inferred from the force on the tethered swimmer and vice versa; A tethered swimmer dissipates more energy than a free swimmer; It is possible to swim with arbitrarily high efficiency, but it is impossible to pump ...