FROUDE VERSUS FROUDE IN FISH LADDER DESIGN

Abstract

Hydrodynamic modelling is based on the similitude theory and the dimensional analysis. The complexity of flows in different geometric environments and fluids, requires the use of the similarity criteria in both the construction of a physical model and a numerical simulation model. That is why expressing a criterion of similarity is important. In modelling of open channel flows, the Froude similarity criterion is used. By definition, as a ratio between the force of the inertia and the weight mass, the Froude number is dependent on the square of the velocity. And yet, there are situations in which the Froude number expression is preferred as linear speed dependence. The paper shows that the way of expressing the Froude number is especially important when we scale and design a fish ladder or fish passage.

Keywords

• the Froude number
• hydrodynamic modelling
• fish ladder