rasidual in each cell, location of the cells with maximum residuals
 

Hi,

is there any posibility to show me the positions of the cells, which have the highest residuals?

I couldn't find something in the manual...


THX!

One thing you can do, is create a user-defined field function which correspond to your model.

If you are using an incompressible, then
= 0

Therefore, if you create a field function which is div(V), it should show values near 0 in each cell.

The value I suggest you display will not be the same as residuals, but at least it can show you what part of the domain is less precise.

You can also create field-function for momentum equations, and eventually energy and turbulence, if you want to.

residuals
 

Hi

There is an easier way.

If you're using the segregated solver then:

solver -> segregated flow-> check the temporary storage retained box in the expert properties window

and run for 1 iteration.

The momentum residuals will be written out to field functions.

azt

ok thx...

now i've got field functions with the residuals... but how can i see the distribution over the cells... a scalar scene didn't show anything...

stuff
 

Hi
you should be able to plot these as a scalar field.

you can createa report that gives you the max and min values. You can then create a threshold with say the top 10% and bottom 10% value and plot this.

That's how you do it.

azt

hm... i don't get any scalar-field plots.

i created a new scalar scene. Under displayers/Scalar 1, I added (under Parts) my fluid region. Under scalar field, i choose a Residual-field-function and nothing is happening.

It seems that this values are empty... because it does not show any Min/Max Values.

edit:

i forgot to say, that i am using a cluster... so on my desktop-pc, the values are available... is there any way to save the field functions in the .sim file?

there is another question: some residuals are negative... is there a way to get the values of residuals, which are displayed in the residual-plot?

stuf
 

hi

you can't save temporary storage stuff to the sim file, which is a real pain. However you can write out the scaler field to a table file, and read it in later on.

azt

hi, thx! can you give me a short instruction, how to write out a scalar field to a table file?

hi
tools -> tables -> right click -> new table -> xyz internal table

chose parts and scalars you want to export

then right click -> extract then right click export

Read this file in later and create a field function using the function InterpolatePositionTable

see help for syntax

azt

sorry for my late answer! i will try it, thx!

Sry for this post. After I read azt´s answer I thought this option for temporary storage retained is only available for segregated and posted my question. But you can use it for coupled or turbulence solvers, too. I wanted to delete my post, but couldnt find a way to do it.