Creating and Editing Diffusive Mass Flux Links

In addition to the Definition tab, Cell pathway elements in GoldSim have three additional tabs at the top of their editing dialog: Inflows, Outflows, and Diffusive Fluxes:

The Inflows and Outflows tabs are used to create advective and several special purpose mass flux links.

The Diffusive Fluxes tab is used to create diffusive flux links involving the current pathway.

To create a new Diffusive Flux (a mass flux link from the current pathway to another pathway), do the following:

3. Press the Add Flux button. This will bring up a browser showing all of the other pathways (or Containers with pathways) in the model.

5. GoldSim will then display the dialog for selecting the media involved in the mass flux link:

If you change your mind or have selected the wrong pathway, press the Select… button to change the pathway.

The two fields labeled Fluid in this dialog are drop lists containing all of the fluids in the corresponding pathways. (If the mass flux link involves a Pipe, External or Network pathway, the medium involved in the link must be the Reference Fluid, and this will be the only choice in the list.)

The default Link Type for a Diffusive Flux between Cells is Coupled (and, by definition, it cannot be changed). The default Link Type for a Diffusive Flux to a non-Cell pathway is Normal (and, by definition, it cannot be changed to Coupled).

6. You will then be returned to the Diffusive Fluxes tab. Move your cursor to the Properties of Selected Diffusive Flux section and enter the Lengths for the two sides of the link. The value must be non-negative. At least one of the lengths must be non-zero.

7. Select the porous medium on each side of the link. The drop-list will include all solids located in the pathway. You do not have to select a porous medium (the default is "none").

9. If you wish to save the mass flux Final Values or Time Histories for the link, select one or both of the checkboxes.

Note: If the diffusive flux link involves a non-Cell pathway, the Length and Porous Medium will be grayed out for that side of the connection and set to 0 and none, respectively, since GoldSim assumes that there is no diffusive resistance on the non-Cell side of a diffusive mass flux link.

After a diffusive flux is created, you can always change the properties of the flux (i.e., the lengths, diffusive areas, porous media, and whether or not results are to be saved) by selecting the diffusive flux in the top of the dialog (by clicking on the appropriate row in the List of Diffusive Fluxes) and editing the properties in the lower section of the dialog (Properties of Selected Diffusive Flux).

The Diffusive Fluxes tab only displays the pathway name, and does not indicate where the pathway exists in the model. If, however, you hold your cursor over a pathway in the list, a tooltip displays the full containment path for the pathway.

Note: Once a Diffusive Flux is created, you cannot change the fluids which are involved. The only way to change the fluids is to delete the Diffusive Flux and recreate it.

A Diffusive Flux is deleted by selecting it in the top of the dialog (by clicking on the appropriate row in the List of Diffusive Fluxes) and pressing the Delete Flux button.

When you create a diffusive mass flux link, the link automatically appears in the Diffusive Fluxes tab of both pathways. The properties of the mass flux link can be edited from either location.

Note: The Diffusive Fluxes tab is only available for a non-Cell pathway after a diffusive link has been made to it. Furthermore, the Add Flux button is disabled for non-Cell pathways, preventing you from creating new diffusive flux links (i.e., you can only create new diffusive flux links from Cell pathways).