Three-dimensional calculation of scour around a cylinder

# Three-dimensional calculation of scour around a cylinder

## Abstract

The flow of water around a cylinder was calculated by a numerical model. The model used
a finite volume method to solve the non-transient Navier-Stokes equations for three
dimensions on a general non-orthogonal grid. The k-e turbulence model was used to
solve the Reynolds-stress term. The flow field gave the shear stress on the boundaries,
which was used to calculate sediment concentration for the bed elements.
The diffusion/convection equation for the sediment concentration was solved and continuity
for the sediment concentration gave changes in the bed elevation. Using the modified bed,
a new flow field was calculated, and also a new sediment concentration. This sequence
was repeated until the depth of the calculated scour hole was identical to the depth of
the scour hole from a physical model study. The rest of the geometry of the resulting
scour hole compared well with the measured scour hole from the experimental study.
Also other flow characteristics given by the numerical model were found to be in agreement
with observations from the experimental study.