Longitudinal Thermocapillary Flow over a Dense Bubble Mattress

Interactive actuation of multiple opto-thermocapillary flow-addressed bubble microrobots

Opto-thermocapillary flow-addressed bubble (OFB) microrobots are a potential tool for the efficient transportation of micro-objects. This microrobot system uses light patterns to generate thermal gradients within a liquid medium, creating thermocapillary forces that actuate the bubble microrobots. An interactive control system that includes scanning mirrors and a touchscreen interface was devel...

High friction on a bubble mattress.

Reducing the friction of liquid flows on solid surfaces has become an important issue with the development of microfluidics systems, and more generally for the manipulation of fluids at small scales. To achieve high slippage of liquids at walls, the use of gas as a lubricant--such as microbubbles trapped in superhydrophobic surfaces--has been suggested. The effect of microbubbles on the effecti...

Why bumpy is better: The role of the dissipation distribution in slip flow over a bubble mattress

It has been observed that the amount of effective slip for transverse flow over a bubble mattress is maximum for bubbles that protrude somewhat in the channel flow. In this paper we provide an explanation for this characteristic feature by analyzing the spatial distribution of viscous dissipation for bubbles of varying protrusion angles. Bubbles protruding in the channel act as obstacles and re...

Thermocapillary Flow Near a Cold Wall

The thermocapillary feedback mechanism important at the edge of weld pools and other materials processes is examined through a model problem A pool of liquid with a at horizontal free surface is bounded on one side by a vertical solid wall which is maintained at a cold temperature to unit depth and at a warmer temperature below far away the uid is at the warmer temperature Surface tension is a ...

Fundamental effects in nanoscale thermocapillary flow