Microscale fluid flow induced by thermoviscous expansion along a traveling wave.
The thermal expansion of a fluid combined with a temperature-dependent viscosity introduces nonlinearities in the Navier-Stokes equations unrelated to the convective momentum current. The couplings generate the possibility for net fluid flow at the microscale controlled by external heating. This novel thermomechanical effect is investigated for a thin fluid chamber by a numerical solution of the Navier-Stokes equations and analytically by a perturbation expansion. A demonstration experiment confirms the basic mechanism and quantitatively validates our theoretical analysis.
Applied Physics and Center for NanoScience, Department of Physics, Ludwig-Maximilians-Universität München, Amalienstrasse 54, 80799 München, Germany.
Franz M
FM
Weinert
Jonas A
JA
Kraus
Thomas
T
Franosch
Dieter
D
Braun