Flow visualization of Bénard convection using holographic interferometry.

An application of holographic interferometry to Rayleigh-Bénard flow is reported. A fluid seeded with fine alumina particles is illuminated with sheetlike light, and the light scattered from the plane is recorded in a hologram. The reconstructed images give 2-D full-field velocity information within the volume of moving liquid at any instant in time. The convective rolls are regular and oriented perpendicular to the long side of the cell. The vertical velocity distribution closely approximates a sinusoidal function of the horizontal distance and its maximum is nearly proportional to the half-power of the reduced temperature.