Matter Dispersion Due to Boundary Layers in Oscillatory and Rotating Fluid

Abstract

Matter dispersion due to the shear effect of currents is investigated theoretically as one of the mixing dilution processes. The shear is generated in the boundary layer as Stokes or Ekman layer which is given by motion equations. Dispersion of suspended matter with its own settling velocity is also analyzed besides that of passive matter. Both kinds of matter are strongly dispersed only in the boundary layers at the initial stage. As the time proceeds, the dispersion coefficient of passive matter gets inversely proportional to the water depth in the oscillatory current, while that of suspended one with a certain settling velocity is independent of the depth and fairly larger than that of passive one. However the dispersion coefficient of suspended matter gets slightly larger with increase of the water depth although that of passive one is not so dependent on it as suspended one.