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Transfer Matrix in an acoustic problem in a Catalytic Converter

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Hi, I'm trying to calculate the Transmission Loss in a Catalytic Converter. I apply an initial value of pressure of 1 Pa and I'm trying to replace the monolith by a transfer matrix. The model I use is 2D axisymmetric.

I define inlet and outlet boundaries with the intention of apply values of pressure and normal velocity on them. The problem is that I want to use every value of pressure and velocity on every node of the boundary, so the average definition doesn't suit for me (I use a monolith radius of 0.15 metres). I tried to define TL and the elements of the transfer matrix (T11, T12, T21 and T22) as global variables, p_inlet=acpr.p_t and v_inlet=acpr.vz as variables on the inlet boundary and p_outlet=acpr.p_t and v_outlet=acpr.vz on the outlet boundary, all of those variables in the component.

Then I think I have to use the normal velocity on the inlet and the outlet boundaries as it follows:

Inlet --> vn=-(T12*p_outlet+T22*v_outlet)
Outlet --> vn=-T21*p_inlet+T11*v_inlet

Am I right?

So, what I would like to know is the way to apply those values of pressure and normal velocity on every node of the inlet and the outlet boundaries, not just using an average value on them.

I hope you understand my problem. Thanks!

0 Replies Last Post 29.05.2016, 06:41 GMT-4
COMSOL Moderator

Hello Carlos Villar

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