Thermal Convection in a Strongly Stratified Two-Dimensional-Like Fluid
Department of Physics and Astronomy, University of Pittsburgh
Thermal convection in a freely suspended liquid film is created by subjecting the film to a vertical temperature gradient. Despite the stable density stratification, intense velocity and density fluctuations are observed. It is found that velocity field is strongly intermittent in the buoyancy sub-range, which was thought to be nonintermittent. The velocity structure functions Sq(l)(=<| \zeta vlq|>) exhibit self-similar structures and can be described by power laws l\zetaq for 1<q<8. By extending Kolmogorov’s refined similarity hypothesis to our system, an analytical form is derived for the scaling exponent \zetaq and is compared to our measurements. We will also discuss other issues, such as scalar mixing and equipartition of kinetic and potential energy, encountered in the experiment.