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(HELP!!!) Integration coupling variables problem

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integration coupling variables->boundary variables problem

I am simulating a fluid flow using Poisson's equation in a 2d environment(2d square).
Fluid is taken as it is entering from the top boundary and exits from the bottom.
And there is not pressure on the side walls so no fluid flows through side walls.

In the simulation the fluid is supplying nutrients to cells, nutrient supply is modeled by the convection and diffusion equation.

I want to find the mean velocity, Ud at y=d, at the top boundary(boundary 3) with an expression k*Py and destination to be the sub domain 1.

I entered these values in "integration coupling variables->boundary variables". When I solve for the initial concentration of Nutrients (solution of the convection and diffusion) I am getting an error.

Please help me!

3 Replies Last Post 19 lug 2015, 09:35 GMT-4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 9 years ago 17 lug 2015, 02:58 GMT-4
Hi

it would be easier for us to understand if you join in the model too ;)

--
Good luck
Ivar
Hi it would be easier for us to understand if you join in the model too ;) -- Good luck Ivar

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Posted: 9 years ago 17 lug 2015, 03:34 GMT-4
Thank you for the reply

Attached is the comsol file(I am using comsol 3.5),

I want to find the initial value of N.

These are the steps I followed, Solver manager->initial value expression + use setting from initial value frame

then in the "solve for" tab solve "heat equation"

I got an error when solving this, But when I take out the mean velocity term it worked.
Thank you for the reply Attached is the comsol file(I am using comsol 3.5), I want to find the initial value of N. These are the steps I followed, Solver manager->initial value expression + use setting from initial value frame then in the "solve for" tab solve "heat equation" I got an error when solving this, But when I take out the mean velocity term it worked.


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Posted: 9 years ago 19 lug 2015, 09:35 GMT-4
anyone there?
anyone there?

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