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Hi

you can enter a boundary condition as a value (numerical constant) but also as a function of x, y etc.

If you are in 2D the easiest is to use the default line dimension "s" that COMSOL defines going from 0 to 1 along an edge (in the sens of the arrow seen in edge view mode).

to get a quadratic shape you can write

MyBoundaryCondition = MyMaxValue*s*(1-s)

to normalise it you might want to add a constant such as 4 or 6 depending on what you are looking for (mean or max values)

THis is typically used for laminar flows in a pipe or between two fixed no-slip walls, se the CFD doc

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Good luck
Ivar

Dear Ivar,

Thanks for reply.

I am trying to learn COMSOL because I know this is very good software. I do not know default line dimension. How I am trying to solve this problem, please see attachment for that. I will be very grateful if you help me with this.

Thanks in advance


With regards

Ricky

Hi

you should make a function of the type interpolation, add the data array and call it on the BC data field.

I'm not sure now (would have to test it out and I'm not by my COMSOL computer) how to "send" the dependent variables so either its a myfunct(y) or a myfunction(s)

note that "s" varies from 0 to 1 along the edge in the direction of the arrow so you must normalise the length and your function accordingly. Whyle y takes the value of the element whereever it is positionned along the line

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Good luck
Ivar

Dear Ivar,


Thank you very much.

i will try this method.

with best regards

Ricky