# GfsSourcePipe

### From Gerris

GfsSourcePipe implements models for culverts within the GfsRiver Saint-Venant solver. A matching source and sink is added to the cells containing the end points of the pipe. The intensity of this pair is given by a culvert model relating the flow rate through the pipe to the state variables (water depth and momentum) at either ends of the pipe and the characteristics of the pipe (geometry, roughness etc...). Care is taken so that the time-integration of these terms does not lead to undershoots or overshoots of the state variables.

The default model implemented in GfsSourcePipe assumes that the hydraulic radius of the pipe is constant and the flow rate is given by the Gauckler-Manning-Strickler empirical formula, with a constant Gauckler-Manning coefficient of 0.03. Note that this requires SI units to be used in the rest of the model to be consistent.

The syntax is

[ GfsSourceGeneric ] (X1,Y1) (X2,Y2) DIAMETER

where `(X1,Y1)`

and `(X2,Y2)`

are the coordinates of the endpoints and `DIAMETER`

is the diameter of the pipe.