Dummies Guide to Min/Max Mass Flow Constraints?

In the online help manual, we are given the following definition;

[quote]The application of a mass-concentration boundary condition can be limited by a minimum and/or maximum mass flow set as a constraint. If the flow at the node exceeds a set maximum, the concentration boundary condition is converted into a well condition with the value of the maximum mass-flow constraint. If the mass-flow falls below a specified minimum mass-flow, a well condition with the minimum value is applied.[/quote]

What is meant by a 'well condition'?


And, in the example seawater interface, why are these constraints placed on the seaward boundary?

Mass nodal sink/source BC can be also considered as a "Well condition" for the mass species. However, I agree that using the name Well condition might be a bit misleading in this context.  The help manual refers to a Mass nodal sink/source BC which is the complementary form of the Mass-concentration BC.

Let me anser your second question: Those constraints are put as FEFLOW does not require a fixed-concentration BC when water flows out of the system at a boundary. Thus it is good practise to apply the fixed-concentration BC only for water inflow - and this is what the constraint with a value of 0 does.

Fantastic.

My thanks for both of your responses!