Posted Fri, 20 Oct 2017 07:57:04 GMT by Alex Costall PhD Student

What do I need to set in order to allow mass-concentration to expand past the mesh limit?


In the picture below, the mass-concentration boundary node is clearly prohibiting the 'normal' movement of the seawater.

The node is currently set to a mass-concentration of 200 mg/L. The plume is about 20000 mg/L.

I'm sure this is related to the min/max mass-flow constraints, but I can't work out the right parameters :(

[img width=140 height=200][/img]
Posted Thu, 26 Oct 2017 06:58:14 GMT by Björn Kaiser
Could you please attach the picture to your post?
Posted Fri, 27 Oct 2017 04:47:26 GMT by Alex Costall PhD Student
Done - sorry. Didn't see the option on the first pass.
Posted Tue, 07 Nov 2017 09:19:56 GMT by Björn Kaiser
If I understand you correctly, you want to allow mass flowing out of the system (model domain) and prohibit mass entering the system. If this is true, you can use a fixed mass Boundary Condition (type Dirichlet) on top of a flow Boundary Condition. Then, you may constraint the mass Boundary Condition with a minimum mass flow of 0 g/d as you already indicated. In this configuration, the Boundary Condition for mass is only active as long as water is entering the system. If water leaves the system, mass is transported out by the advective mass transport component (convective formulation of the transport equation).

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