Modelling Heat transfer between stack and gas in Thermoacoustic
 

Hello,

I am trying to simulate thermoacoustic phenomenon in FLUENT.

For that the geometry is as shown in fig. 1. Enlarged view of stack portion is shown in fig.2

Stack wall is given the known steady (with respect to time) temp gradient from 700 K to 300 K from left to right using UDF.

Heat transfer coefficient between stack wall and gas is 50 W/m2 K.

Now I am able to give temperature gradient using UDF but simultaneously how can I give heat transfer coefficient condition.

I am facing problem in define this boundary condition in FLUENT.

Can any one guide me about this..????????

Thanking you in anticipation....