# Velocity Profile of previous simulation as inlet for another

 Register Blogs Members List Search Today's Posts Mark Forums Read

 June 25, 2020, 02:06 Velocity Profile of previous simulation as inlet for another #1 New Member   GenD Join Date: Nov 2017 Posts: 23 Rep Power: 8 Hi, I was wondering about cutting my simulation and geometry into some parts in order to meet computational possibilities of my computer and have better results. That's why I was thinking about putting velocity profile (or other if it's better) of outlet into inlet of next simulations. Is there a way to do this? Is it through UDF? And the last question, is it a good idea generally? Will this approach affect on something badly?

 June 26, 2020, 08:30 #2 Senior Member     André Join Date: Mar 2016 Posts: 133 Rep Power: 10 You should be able to take the profile of one simulation and use that input into another simulation... but what exactly are you trying to model? You can also specify periodic boundary conditions that take whatever goes through one boundary to feed it back into the other (e.g. in a pipe flow the flow going out through right comes right back in on the left which can allow you to study a fully developed flow in a relatively short domain) __________________ Sapere aude!

 June 26, 2020, 13:31 #3 New Member   GenD Join Date: Nov 2017 Posts: 23 Rep Power: 8 But how to connect those profiles? In this case, I'm not modeling anything. It's just a idea to be used in future, because of computer limitations. Let's say it will be some flow through tank with porous plates. I would have just divide this tank into ... three parts and then try to simulate it respectively.

 June 26, 2020, 16:57 #4 Senior Member     André Join Date: Mar 2016 Posts: 133 Rep Power: 10 It sounds like you want to cut them to run it on different computers?? __________________ Sapere aude!

 June 26, 2020, 18:27 #5 Senior Member   Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,689 Rep Power: 66 It's a little confusing because there's a method of writing profiles in fluent that's quite literally called a profile. Write a PROFILE at the outlet of your first simulation and then read it into the next simulation. Then you can use this profile/PROFILE as a BC.

 June 27, 2020, 02:33 #6 New Member   GenD Join Date: Nov 2017 Posts: 23 Rep Power: 8 acalado, No, not on different computers. On the same one, but one simulation after another. LuckyTran, that was my first thought to create a UDF. I know how to do this generally, but I don't really know how to read profile of outlet (it won't be pretty laminar flow, but highly turbulent) in a form, which can be used then as Profile UDF of inlet. Do you know some useful macros or tips in order to do this?

 June 27, 2020, 08:39 Profile #7 Senior Member     Vinerm Join Date: Jun 2009 Location: Nederland Posts: 2,946 Blog Entries: 1 Rep Power: 36 You don't require a UDF. Profile is written using File > Write or using TUI commands for the same. You need to write profiles for each field variable and not just velocity. Reading profile is same as writing, i.e., File > Read and then go to the boundary to apply the profile. However, there is one concern and it could have very significant effects. If the flow is unidirectional at the location where you cut the domain, then it is alright, otherwise, this would require multiple iterations, i.e., you have to do calculations for each domain many times if the profiles at the boundaries are not unidirectional. __________________ Regards, Vinerm PM to be used if and only if you do not want something to be shared publicly. PM is considered to be of the least priority.

 June 27, 2020, 19:37 #8 New Member   GenD Join Date: Nov 2017 Posts: 23 Rep Power: 8 Sounds like a simple plan. I will try to achieve it, when I will model something worth of trying. Thanks for your help. Offtopic: Do someone have idea by which UDF macro I can read data of profile?

 June 28, 2020, 03:27 #9 Senior Member   Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,689 Rep Power: 66 You don't need a UDF, stop obsessing over it

 Tags cfd, few simulations, profile