Laboratory Modeling of Buoyant Jet in a Rotating Fluid

Abstract

The “late” stage of the spring thermal bar phenomenon in lakes and marginal seas is characterized by formation and offshore propagation of warm buoyant jet (Chubarenko and Demchenko, Acta Geophys 55(1):56–64, 2007). In this work, an investigation of the regularities of warm buoyant jet propagating in a rotating and nonrotating laboratory circular tank with sloping or horizontal bottom is undertaken. To reproduce the warm buoyant jet, a thin circular heating cable belt was used. It was mounted at the top of water layer along a round wall of the tank filled by distilled water. More than 20 experimental runs were performed for various values of specific power supply, q, and Coriolis parameter, f, including f = 0 (nonrotating fluid). It was found that the buoyancy flux and Coriolis parameter are the key variable dimensional parameters influencing the dynamics of the warm buoyant jet in a rotating fluid. The dimensionless parameters governing this process are the flux Rayleigh number Ra, and the Ekman number Ek. The experiments have demonstrated that the nondimensional radial velocity of jet propagation depends on Rayleigh and Ekman numbers in the form of $U/{B^{{1/3}}} = 1.2 \times {10^{{ - 2}}}R{a^{{1/2}}}\user2{Ek}$ for rotating case and on Rayleigh number in the form of $U/{B^{{1/3}}} = 2\, \times {10^{{ - 6}}}R{a^{{1/2}}}$for nonrotating case.