Effects of Schmidt Number on Turbulent Mass Transfer Around a Rotating Circular Cylinder

Characteristics of turbulent mass transfer around a rotating circular cylinder have been investigated by Direct Numerical Simulation. The concentration field was computed for three different cases of Schmidt number, Sc = 1, 10 and 100 at Re* = 336. Our results confirm that the thickness of the Nernst diffusion layer decreases as Sc increases. Wall-limiting behavior within the Nernst diffusion layer was examined and compared with those of channel flow. Concentration fluctuation was found to be time-scaled with (r⁺)² while the time scale ratio equals the Schmidt number throughout the Nernst diffusion layer. Scalar modeling closure constants were determined, and turned out to vary considerably within the diffusion layer.