Comparison between numerical and experimental results on thermoconvective instabilities of a high-Prandtl-number liquid.

The flow structuration of silicon oil (Prandtl number of 10.3) in a open cylindrical pool heated from the center of the surface is investigated numerically. Our purpose is to perform the numerical simulation of experimental results obtained by Favre [Phys. Fluids 9, 1473 (1997)] who observed transitions between steady and axisymmetric flows at sufficiently low values of the Marangoni number (Ma) and various types of instability depending on the height of the fluid. The hydrothermal wave regime has been obtained at critical values of Ma which depend on the Bond number and on the aspect ratio. The numerical results are in good agreement with the experimental ones.