On thermocapillary rings from radioactive particles suspended at the surface of liquids

Abstract

Thermocapillary motion and its significance with regard the thermal behavior of heat sources and with particular reference to radioactive particles suspended in fluids is discussed. It shown that because the heat source, a thermocapillary flow is induced with the viscous liquid flowing outwards from the particle and then with a drag force propelling the surrounding suspended material away with the formation of a diffusive ring. Utilizing a simplified physical model, it was found a power-law for the concentration of particles surrounding the hot particle. The formation of such a ring may be important as a visual simple way to detect or unveil the presence of radioactive particles suspended in lakes, rivers, ponds or aquifers after,say, an accidental atmospheric release, a new method for detection under controlled conditions or in geophysical science. Computational Fluid Dynamics (CFD) simulations were performed which agree qualitatively and quantitatively well with the analytical model.