A dense cohesive sediment suspension, which contains primarily clay
particles, is a thixotropic non-ideal Bingham fluid with a true yield stress. Its timedependent
rheological behaviour can be described by the structural kinetics theory
in which the yield stress is taken as a measure for the structural parameter. This
theory allows the construction of a more general equation of state, which is
independent of the rate equation. The applicability of the model is demonstrated by
examples of the prediction of constant structure curves and of transient behaviour.
The thixotropy model is incorporated into a Navier-Stokes solver to simulate the
flow behaviour in a Couette viscometer.