CCHE3D Sediment Transport Model

CCHE3D-SED is a module of the CCHE3D model. Sediment transport is simulated by using the 3D flow variables provided by CCHE3D flow model. The following is the capabilities of the model for pier scour process simulation:

  • Non-equilibrium and non-uniform bed load transport model
  • Non-uniform suspended sediment transport
  • Bed layer sediment composition change
  • Bed elevation change due to erosion and deposition
  • Avalanche module
  • Bed-slope effect for sediment particle entrainment
  • Downflow induced turbulent flow impact to entrain sediment around the pier foot (local scouring).

Bridge Pier Scour Module

Bridge failures are often resulted by local scour around piers, where the turbulent flow takes away sediments or protection materials and cause the pier and the bridge to fail.

3 dimensional models are often used to simulate local scouring problems, in which the sediment transport around in-stream hydraulic structures is affected by highly 3D turbulent flow.

Computational mesh around the cylindrical pier

A photograph of the final scour hole of an experiment

Simulated scourhole profile is compared to the observed one.

The agreement in the front of the pier is very good, but that in the weak zone is less accurate.

Comparison of simulated and measured scour hole depth development.

Simulated flow field in a scour hole at the end of an experiment. The color shading in the horizontal plane indicates the bed elevation. The color shading in the vertical plane indicates the magnitude of the approach flow velocities. The structure and shape of the horse shoe vertex in the scour hole is seen clearly.