The Onset of Viscoelastic Rayleigh-Benard Convection

Rayleigh-Benard convection in aqueous solutions of polyacrylamide is visualized using holographic interferometry. The results confirm and extend earlier findings of the present authors which showed that the critical Rayleigh-number Rac for the onset of free convection in viscoelastic fluids can be significantly increased as compared to Newtonian fluids depending on the properties of the polymer and the polymer solution. The present results were obtained in an improved test chamber with well defined electrical conductivity of the solvent.