EFFECTS OF VORTEX SHEDDING ON THE BENTHIC OXYGEN TRANSFER - A COMPARISON BETWEEN ANALYTICAL CALCULATION AND EXPERIMENT -

A laboratory experiment regarding diffusive oxygen transfer rate at rough sediment surface was conducted to compare with the analytical calculation, considering vortex shedding in the benthic boundary layer and biochemical reactions in the sediment. The reproducibility of the experimental results by analytical calculation was considerably improved by including terms for vortex shedding frequency in the diffusive boundary layer between the roughness elements and for non-steady variations in the diffusive oxygen transfer rate due to instantaneous changes in oxygen concentration in the flushed region. A simple method to estimate enhancement effect for Stanton number, which is a non-dimensional diffusive transfer rate relative to the mean velocity, the mean concentration in the bulk region, and the mean concentration at the sediment-water interface, caused by occurrences of vortex shedding was also presented.