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-mAx- February 4, 2014 04:02

FloEFD STDOUT protocol
While running FloEFD with commands (batch), there is a possibility to watch what the solver is doing (in the "shell" or in a .stdout file)
I was looking for the travel number in this file, but without success.
Is there any litterature or some explanations for this protocol?
Thanks for any info

Boris_M March 5, 2014 09:23

Hi Maxime,
The stdout is not originally meant to be read by customers. It is more as a first instance to see what whent wrong during solving for our developers.
Is there a reason why you need to know the travels?
You can find the iterations in the stdout but the travels is jsut an artificial number for the user to have an idea of what is the smallest unit until comparing the convergence makes sense. The travels can vary depending on the model and mesh size. It basically tells the amout of iterations that are necessary for a disturbance to pass through the domain.
You will see that very nicely if you take the ball valve tutorial for example and define water as the default concentration of 1 and any other liquid as a second fluid but not as the initial concentration (water 1, other 0). Now use the inlet boundary condition with the other liquid flowing in. You can see how the other liquid concentration is expaning in the flow as it progresses with each iteration and roughly at 1 travel the other liquid has fully reached the outlet and leaves only some slight convergence in the distribution or other parameter such as pressure and velocity convergence to fulfill the convergence criteria.


-mAx- March 6, 2014 03:54

Hello Boris,
Actually I need to see what is the value of current travel , especially when I come at the office and I ran several runs in a batch (no GUI)
I set my runs with a limit of max Travel. Then I could see if current run is almost done (or not)

Boris_M March 6, 2014 12:12

Hi Maxime,
let me check if there is any way of calculating it manually or if it can be found in the stdout.
I'll get back to you as soon as I hear from the developers.


Boris_M March 7, 2014 12:32

Hi Maxime,

the Travels are calculated as 2*(total cell number)^(1/3)

The total cell number should be listed in the stdout.


-mAx- March 10, 2014 02:45

Thank you Boris
I appreciate
But as far as I know with the GUI (solver) we can see Travels while iterating. I mean the Travel number is increasing with iterations.
So if I don't have refinemenent anymore, the total number cell number is fixed but the travel number should increase. That means at least one variable is missing in your travel definition. (I guess)

Boris_M March 10, 2014 08:32

Oh, no. That was not quite good described by me. The equation gives the number of Iterations that are necessary for 1 Travel. So in case you have 1 Million cells the "iterations per 1 Travel" is 200. So the Travels you are looking at is just the ratio between the actual number of iterations and the iterations per 1 travel. Hence, at 125 iterations the Travel is 125/200=0.625

I hope this is clearer now. Sorry for that.


-mAx- March 10, 2014 08:39

Yep, now it's clear
Thank you

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