CONVECTION-DIFFUSION OF SEDIMENT IN NONUNIFORM FLOWS BY THE FINITE-ELEMENT METHOD

In connection with the mechanics of sedimentary ripples and dunes in alluvial channels, the convection-diffusion of suspended sediment in nonuniform flows is solved using the finite-element method. The fluid motion is modeled as a rotational inviscid flow field. The finite-element formulation for the convection-diffusion problem allows one to specify either the diffusive flux or the sum of the finite-element result with the finite-difference result and with an analytical solution of a test problem shows good agreement. The convection-diffusion of suspended sediment over an actual dune is also analyzed and compared with the field data. Comparison shows good agreement.