Discretization of gradient vector - unstructured mesh

Dapb · June 14, 2012, 05:28

Hello,

I have an unstructured triangular mesh that has two different zones (on bottom: zone1, on top: zone2). To impose the boundary condition at the interface, I have these equations:

a [grad(T)*n]1 + b = c [grad(T)*n]2 + d
Tf1 = Tf2 = Tf (interface values)

where the indices 1 and 2 designate the zone and a, b, c and d are constant.

I would like to know how can I descretize the scalar product grad(T)*n at the interface (if it was a structured mesh, I could use (Tf-T1)/ds and (T2-Tf)/ds, but this is not the case) to can impose the value of Tf at the interface.

Thanks in advance

Dapb · June 15, 2012, 04:54

Another question:

Instead of imposing the value of Tf, is there a way to impose directly the flux at both interfaces (interface and interface_SHADOW) even in this situation:

flux(interface) = a [grad(T)*n]1 = c [grad(T)*n]2 + d - b

flux(interface_SHADOW) = c [grad(T)*n]2 = a [grad(T)*n]1 + b - d

I tried to do it using C_T_G(c,t) in the function DEFINE_PROFILE(name,t,i) to calculate grad(T) in the zones 1 and 2, but Fluent pointed out an error.

June 14, 2012, 05:28	Discretization of gradient vector - unstructured mesh	#1
Dapb New Member Join Date: Jun 2012 Posts: 5 Rep Power: 14	Hello, I have an unstructured triangular mesh that has two different zones (on bottom: zone1, on top: zone2). To impose the boundary condition at the interface, I have these equations: a [grad(T)n]1 + b = c [grad(T)n]2 + d Tf1 = Tf2 = Tf (interface values) where the indices 1 and 2 designate the zone and a, b, c and d are constant. I would like to know how can I descretize the scalar product grad(T)n at the interface (if it was a structured mesh, I could use (Tf-T1)/ds and (T2-Tf)/ds, but this is not the case) to can impose the value of Tf at the interface. Thanks in advance Pravaah likes this. Last edited by Dapb; June 15, 2012 at 04:55.*

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June 15, 2012, 04:54		#2
Dapb New Member Join Date: Jun 2012 Posts: 5 Rep Power: 14	Another question: Instead of imposing the value of Tf, is there a way to impose directly the flux at both interfaces (interface and interface_SHADOW) even in this situation: flux(interface) = a [grad(T)n]1 = c [grad(T)n]2 + d - b flux(interface_SHADOW) = c [grad(T)n]2 = a [grad(T)n]1 + b - d I tried to do it using C_T_G(c,t) in the function DEFINE_PROFILE(name,t,i) to calculate grad(T) in the zones 1 and 2, but Fluent pointed out an error.