Regensburg 2016 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 50: Wetting, Nano- and Microfluidics I (joint session CPP/DY, organized by CPP)
CPP 50.7: Talk
Thursday, March 10, 2016, 11:30–11:45, H42
Hydrodynamic cavitation in Stokes flow of anisotropic fluids — •Tillmann Stieger1, Hakam Agha2, Martin Schoen1, Marco G. Mazza2, and Anupam Sengupta3 — 1TU Berlin — 2MPIDS Göttingen — 3Massachusetts Institute of Technology
Cavitation is ubiquitous in fluid dynamics, and has significant effects on a wide range of industrial and biomedical applications. Investigations in anisotropic fluids are scarce, and till date, no systematic attempt has been made to study them. Here we report flow-induced cavitation in an anisotropic fluid, studied by combining microfluidic experiments and nonequilibrium molecular dynamics (MD) simulations. Cavitation domains nucleate due to sudden drop in pressure upon flow past a micron-sized obstacle in microchannels, which over time, progressively grows in volume after attaching at the downstream obstacle surface. The inception and growth of cavitation domain ensue in Stokes flow regime. Using MD simulations we study the physical principles governing the cavitation phenomena in nematic liquid crystals (LC), and identify a critical value of Reynolds number Recr for the cavitation inception that scales inversely with the characteristic order parameter of the LC. Strikingly, the critical Recr can be as low as ∼ 50% of the cavitation threshold in isotropic fluids. Corresponding results for the LC in the isotropic phase and for a Lennard–Jones fluid reveal that the drop in Recr is a consequence of the long range ordering in anisotropic fluids. The findings suggest that long range ordering, and its tunability, can be potentially applied as a novel control parameter to modulate cavitation inception in anisotropic fluids.