residuals

fisicas1 · June 5, 2012, 20:32

I have a pipe with heat flux outside and I select for the picture 2 K-epsilon turbulence and the picture 1 Reynolds Stress Turbulence. wath do you think about the Residuals? are it good? or I nedd more iteration? when will I get the best solution? I am new with cfd.

fisicas1 · June 5, 2012, 20:38

I have a pipe with heat flux outside, I have a line of point inside the pipe with a fluid, I should have the temperature the pressure and de Nusselt Number, but for temperature and pressure I have normal result but in the case of Nusselt Number my values are always 0. anyone know what is happening? we can see the pictures.

siara817 · June 6, 2012, 14:32

To make sure which model ( k-epsilon or reynolds ) is proper, you need to evaluate by
1- a real case that exist and you can check some values, such as velocity and compare with the simulation.
2- or check some specific numbers such as drag coefficient in some place of the flow.
What is the reason that the continuity is not converged in the simulation?

fisicas1 · June 6, 2012, 16:06

I can check with the outlet and inlet of the temperature and pressure, or calculate the velocity.

with both I have good result of the pressure (inlet and outlet) but with both outlet temperarure changes 10 ºC-20 ºC which depends the model.

I do not have idea why the continuity is not converged in the simulation?

could you tell me something about Nusselt Number?

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June 6, 2012, 14:32		#3
siara817 Senior Member siamak rahimi ardkapan Join Date: Jul 2010 Location: Copenhagen, Denmark Posts: 172 Rep Power: 5	To make sure which model ( k-epsilon or reynolds ) is proper, you need to evaluate by 1- a real case that exist and you can check some values, such as velocity and compare with the simulation. 2- or check some specific numbers such as drag coefficient in some place of the flow. What is the reason that the continuity is not converged in the simulation?

June 6, 2012, 16:06		#4
fisicas1 Member David L Join Date: May 2012 Posts: 43 Rep Power: 3	I can check with the outlet and inlet of the temperature and pressure, or calculate the velocity. with both I have good result of the pressure (inlet and outlet) but with both outlet temperarure changes 10 ºC-20 ºC which depends the model. I do not have idea why the continuity is not converged in the simulation? could you tell me something about Nusselt Number?