Journal article

Publication year: 1996

Pages: 163-168

Journal: Microgravity Science and Technology

Volume number: 9

Issue number: 3

ISSN: 0938-0108

Publisher: Springer

Abstract: 
Coupled thermocapillary and buoyant convection in NaNO3 floating zones (FZs vertical cylindrical liquid bridge) was studied experimentally. Neutrally buoyant tracer particles or very small ones with double density were suspended in the transparent NaNO3 melt for flow visualization. Tracer particles which initially were suspended homogeneously in the liquid volume accumulated in regions which were determined by the convection pattern. These tracer particle accumulation structures are determined by the convection pattern and on the other hand are outlining it. At slightly supercritical conditions (Ma > Ma(c), where Ma(c) is the critical Marangoni number for the onset of oscillatory thermocapillary flow) the existence of azimuthally travelling waves in the floating zone could be confirmed as these became directly visible due to a specific structure of tracer particle bunching. It was also found that a net flow in azimuthal direction can be present when Ma > Ma(c). These feature of oscillatory thermocapillary convection are new and are not well understood.

Harvard Citation style: Schwabe, D., Hintz, P. and Frank, S. (1996) New features of thermocapillary convection in floating zones revealed by tracer particle accumulation structures (PAS), Microgravity Science and Technology, 9(3), pp. 163-168

APA Citation style: Schwabe, D., Hintz, P., & Frank, S. (1996). New features of thermocapillary convection in floating zones revealed by tracer particle accumulation structures (PAS). Microgravity Science and Technology. 9(3), 163-168.