External Pathway Example: Single Flux Links to/from Cell Pathway

The external pathway provides access to GoldSim's External element for Contaminant Transport constituents. External pathways are extremely flexible. You determine the manner in which the External Pathway operates on the contaminant mass it receives: the External Pathway may be a simple one-dimensional representation, or could be a complex three-dimensional model.

In this model, 1 g/yr of Species1 is discharged into the Source Cell, which flushes immediately into the External pathway. The external pathway provides access to a function in a DLL. In this case, the function simply multiplies the incoming mass by the first optional input argument (in this case, 3) and passes it out with no delay.

You also define the manner in which the External Pathway is linked to the rest of the GoldSim pathway network by specifying the input mass flux links (i.e., the pathway(s) which discharge mass to the External Pathway) and the output mass flux links (i.e., the pathway(s) to which the External Pathway discharges mass). GoldSim then automatically calls the function representing the External Pathway at the appropriate times, passing the appropriate information back and forth between GoldSim and the function.

Integrating external contaminant transport pathways into GoldSim requires that you develop a "wrapper" (or "shell") around your existing function, and compile it into a DLL. In most cases, this will require only a limited number of programming modifications. GoldSim supports both 32-bit and 64-bits DLLs.

To Open the Model File:

1. Start GoldSim
2. Click on the File and select Open Example...
3. Browse to General Examples --> Contaminant Transport Examples
4. Select the file called ExternalPathway.gsm