Convective Velocity Field in the Rayleigh-Bénard Instability: Experimental Results

We used the frequency analysis of the light scattered from a fluid to study the convective velocities in the Rayleigh-Bénard instability. The spatial dependence of the velocity is in agreement with theory. The behavior of the convective flow with the temperature seems to reach the predicted theoretical one only for $R>\mathrm{}1.5\mathrm{}{R}_c$.