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# How to set interior pollustion source?

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I add two point sources at two nodes in RMA4. one node(No.11) locates at the bounary nodestring(rma2) as indicated in the attached pic, and the other node(No.101) locates at interior of the rectangular area.

However when RMA4 runing, only one Node (N0.11) can be identified and calculated.

The .ot3 file said "There are 1 active node boundary condition for time=..."

Computation results shows that the boundary condition was not taken into consideration.

If I only set a node boundary condition at a interior area, it also doesnot work. Countour map shows that the concentration in each point equal to zero. No mass was injected into the caculation area.

So, What's the matter?

What I want to do is to set one pollution source or several pollustion sources in caculation area.

What's intersting is that I had produced a case that there is an interior source in the caculation area and it can run.(see interior source.jpg attached.)

Thanks!

result.bmp

mesh and boundary.bmp

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If I use nodal concentration boundary condition , how I know how much mass was inject to the river

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If I use nodal concentration boundary condition , how I know how much mass was inject to the river

The latest version of RMA4 does not support the BLN (nodal boundary conditions) anymore. If you have done it in the past it was with an older version.

The units for a nodal boundary condition is mass/sec. If you want to know how much mass is in the model, just multiply the boundary condition value by length of simulation.

Cheers,

Cameron

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The latest version of RMA4 does not support the BLN (nodal boundary conditions) anymore. If you have done it in the past it was with an older version.

The units for a nodal boundary condition is mass/sec. If you want to know how much mass is in the model, just multiply the boundary condition value by length of simulation.

Cheers,

Cameron

Thank you Carmeron.

I have another question.:-)

What is the difference between concentration boundary condition and mass loading boundary condition in SMS?

In my view, mathmatically speaking, the former is the 1st kind of boundary condition so that the problem can be defined as boundary value problem in PDE.

However, the latter is not a boundary condition from mathematical point of view, but a Source term in ADE equation.

Thanks.

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