  Fluid flow along microchannels can be induced by keeping opposite walls at
different temperatures, and placing elongated tilted pillars inside the
channel. The driving force for this fluid motion arises from the anisotropic
thermophoretic effect of the elongated pillars that generates a force parallel
to the walls, and perpendicular to the temperature gradient. The force is not
determined by the thermophilic or thermophobic character of the obstacle
surface, but by the geometry and the thermophoretic anisotropy of the obstacle.
Via mesoscale hydrodynamic simulations, we investigate the pumping properties
of the device as a function of the channel geometry, and pillar surface
properties. Applications as fluidic mixers, and fluid alternators are also
outlined, together with the potential use of all these devices to harvest waste
heat energy. Furthermore, similar devices can be also built employing
diffusiophoresis or electrophoresis.
