The Limit Deposit Velocity versus the Particle Diameter
The Limit Deposit Velocity is defined as the line speed above which no fixed or sliding bed is present. Below the Limit Deposit Velocity there is either a fixed or a sliding bed. The Limit Deposit Velocity curve is constructed out of 5 curves and is dependent on the concentration. The graph below shows the 5 curves and the resulting curve for a 17.5% volumetric concentration. The 5 curves are:
The LDV has a lower limit based on the transition line speed between the sliding bed regime and the heterogeneous flow regime. This lower limit depends on the sliding friction coefficient (the brown curves).
The Durand Froude Number FL for the Limit Deposit Velocity versus the Particle Diameter
Since in dredging the concentration is not a constant, the Limit Deposit Velocity curves are plotted in the following graph for concentrations of 1% up to 25%. By doing this a lower and an upper limit can be defined for the Limit Deposit Velocity.
The Bed Fraction & Slip Factor versus the Line Speed
Knowing the Limit Deposit Velocity, the slip factor can be constructed and based on the slip factor, the bed fraction or bed height. Also the spatial volumetric concentration Cvs based on a constant delivered volumetric concentration Cvt is shown.