Spreading and sedimentation from bottom-propagating particle-bearing jets

Laboratory experiments are conducted to examine the evolution of and sedimentation from a particle-bearing jet advancing along a horizontal or downward-sloping boundary underlying a uniform-density ambient fluid. The jet front advances along the bottom while exhibiting a self-similar profile. As the jet propagates downstream, particles settle out, resulting in a teardrop-shaped sediment bed whose geometric parameters are measured non-intrusively using a light attenuation technique. The bed shape is well represented by the theory that assumes a Gaussian radial profile of velocity within the jet and accounts for the bedload transport of particles after they settle. In particular, the bed length is given by , in which is the source momentum flux, is the reduced gravity of the particles and is the particle diameter. The corresponding scale for the sediment depth captures the anticipated order of magnitude for the maximum depth of deposit, but the measurements indicate additional dependence upon , suggesting that the morphology of the bed non-negligibly influences particle settling.