Learning Forum

[Noelly]

Hello,

I ran a periodic simulation on a reduced fluid volume and I am now trying to obtain the full temperature profile after replicating the model along the flow direction.

I did Views> Define (periodic repeats) and set an N number of repetitions, but after that when creating a countour plot, I just get the same periodic model copied and pasted N times.

 

From this section in the user’s guide:

14.4.6. Postprocessing for Periodic Heat Transfer

"The actual temperature field predicted by Ansys Fluent in periodic models will not be periodic, and viewing the temperature results during postprocessing will display this actual temperature field ( of Equation 14–17)"

It seems like what I am trying to do is indeed achievable. Is there something I am missing?

Thank you

[Rob]

The repeats in post processing just copy the result from one section to the next. There is no change in the contour values.  The temperature range shown is for one periodic repeat, ie the section you modelled, based on the temperature input: that's also why there are restrictions in the use of wall thermal settings and solid zones.  

[Noelly]

Thank you, so is there a way to get a scaled up temperature profile as mentioned in section 14.4.6 in the user's manual or not?

[Rob]

Looking at the manual, I'm not sure what you're after.  https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v231/en/flu_ug/flu_ug_sec_periodic_hxfer.html%23flu_ug_sec_periodic_hxfer_wall_post    The temperature field is anchored on the upstream value you set, so the usual approach is to look at variation from that value to answer whatever the model was built to solve. 

[Noelly]

So when the manual says the actual temperature profile is not periodic and that this actual profile could be displayed, I was assuming that if I obtain the temperature field for a 2cm long model, I could replicate the model say 5 times to get the non-periodic temperature field for a 10cm long model made up of the same geometric elements. 

If this is ultimately what I am trying to achieve, is there a way to scale up the temperature difference along the model? Or does it come down to manually calculating the temperature gradient for the submodel that I have and then scaling it up to the actual full-size model?

[Rob]

The grapic repeat is so you can show a "larger" model without running the whole thing. As you know the dT along a section you'd just multiply by however many sections there are. If the temperature changes by a different amount in downstream sections it's not periodic. 

[Noelly]

Thank you!