Journal of Fluid Mechanics


An experimental study on thermal circulation driven by horizontal differential heating

a1 Physical Oceanography Lab, Ocean University of China, Qingdao 266003, Shandong, PR China
a2 Department of Physical Oceanography, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA

Article author query
wang w   [Google Scholar] 
huang rx   [Google Scholar] 


Circulation driven by horizontal differential heating is studied, using a double-walled Plexiglas tank $(20 \,{\times}\, 15\,{\times}\, 2.5$cm$^3$) filled with salt water. For instances of heating/cooling from above and below, results indicate that there is always quasi-equilibrium circulation. In contrast to most previous results from experimental/numerical studies, circulation in our experiments appears in the form of a shallow cell adjacent to the boundary of thermal forcing. The non-dimensional stream-function maximum confirms the 1/5-power law of Rossby, $\Psi\,{\sim}\,Ra^{1/5}_L$. Dissipation rate measured in the experiments appears to be consistent with theory.

For cases of heating/cooling from a sloping bottom, circulation is similar to cases with a flat bottom; circulation is strong if heating is below cooling, but it is rather weak if heating is above cooling. Nevertheless, circulation in all cases is visible to the naked eye.

(Published Online September 27 2005)
(Received April 5 2004)
(Revised March 29 2005)