CFP: Conduit Flow Process Pane

The CFP: Conduit Flow Process pane is on the MODFLOW Features tab of the Object Properties dialog box.

This pane is only visible if the Conduit Flow Process is selected and individual conduits are simulated. This pane can only be selected if the object has one X, Y, or Z formulas.

This pane is used to define the properties of individual conduits and nodes. Nodes in the Conduit Flow Process correspond to cells and conduits connect individual nodes. Some of the properties defined here apply to conduits and some apply to nodes.

Formulas for node properties work the same way as any other formula: the formula is evaluated at each cell to find the value at that cell. If there are two objects that define the properties of the same cell the one that is "in front" of the others will determine what value the node receives. For saving flow and head values at nodes (NODE_NUMBERS), if any of the objects that define a node is supposed to have flow and head values saved, they will be saved for that node.

Formulas for conduit properties work a little differently. The formula is evaluated at each cell and the value for each conduit is the average of the values at the two cells that the conduit connects. Because the formulas are evaluated separately for each object, the formulas for one conduit object do not affect the values assigned for other conduit objects. If two conduit objects happen to connect the same nodes, the object that is "in front" of the others will determine what value the conduit receives.

The following properties are defined on this pane

•DIAMETER: This is the diameter of the conduit in the same length units as are used in the rest of the model. There is a hidden data set named PipeDiameter that can be used display values of DIAMETER.

•TORTUOSITY: This accounts for the difference in length between the straight line distance between nodes and the actual length of the conduit. There is a hidden data set named Tortuosity that can be used display values of TORTUOSITY.

•RHEIGHT: The roughness height "can be obtained by sampling and averaging the height of the conduit wall microtopography. The height of the mean microtopography is used to calculate the roughness." There is a hidden data set named RoughnessHeight that can be used display values of RHEIGHT. The roughness height is measured in the same length units as are used in the rest of the model.

•LCRITREY_P and TCRITREY_P: These are the lower and upper critical Reynolds numbers that determine when flow switches between laminar and turbulent. See Shoemaker and others (2007) p. 31 for a discussion of appropriate values for these parameters. There are a hidden data sets name LowerCriticalR and UpperCriticalR that can be used display values of LCRITREY_P and TCRITREY_P.

•K_EXCHANGE: This is either the conduit wall permeability term or the conduit wall conductance depending on SA_EXCHANGE. See Shoemaker and others (2007) p. 31 for a discussion of appropriate values for this parameter. There is a hidden data set named PipeConductanceOrPermeability that can be used display values of K_EXCHANGE.

•ELEVATION: If the conduit node elevation is set individually for each node, ELEVATION is the conduit node elevation. for objects on the top view of the model, you may wish to use the same formula for elevation and for the Z formula. There is a hidden data set named CfpNodeElevation that can be used display values of ELEVATION.

•PIPE_NUMBERS: Checking this check box will cause the Conduit Flow Process to create an output file for all conduits specified by this object at a frequency specified by T_NTS. The files will be named TUBE<N>.OUT where <N> is the node number.

•NODE_NUMBERS: Checking this check box will cause the Conduit Flow Process to create an output file for all nodes specified by this object at a frequency specified by N_NTS. The files will be named NODE<N>.OUT where <N> is the node number.