Sum velocity fields over time

Svensen · December 25, 2017, 14:49

I have a series of time steps, i.e. t = 0; 1; 2; 3; 4.
I want to create a new vector field like U_sum = U(0) + U(1) + U(2) + U(3) +U(4).

Is it any way to do it using postProcess utility or ParaView ?

HakikiCanakkaleli · December 28, 2017, 17:21

Hi,

I haven't tested below, yet may hopefully give some ideas:

1. In Paraview, Filters -> Alphabetical -> Calculator might be a help.

2.

Code:

postProcess -func add <fields>

might be used.

In addition, Python libraries could be very useful, which I prefer over any other post-processing tools.

KingKraut · January 20, 2023, 06:29

Hey,

did you find a solution for the problem?

The add-function Object only allows the summation of different fields at the same time.

I am currently looking for a tool or trying to implement it myself, which does time integration of a particular field during run time. I am quite amazed that I cannot find such a function object in the OpenFOAM-libraries. I am not sure, if I am just too blind to find ist...

Anyway. I thought by finding a tool, which does additions of the same field for different times, i guess such a tool could easily be modified into a time integration function object.

Of course a proper time integration function object from OpenFOAM would be something I would like much more!

Thanks for any hints or suggestions!!

PS: Still cant believe, such a function object does not exist yet...

Edit: I would like something, that I can use during the simulation run, which is why I am looking for afunction object!

Numericer · January 23, 2023, 15:18

You can modify the solver by creating a new field that reads the previous time value of velocity and writes the sum of that value and the new velocity to the present time folder. This will be done each during each time step, so that in the end you will have sum of all velocties at all times.

You can do the same without modifying the solver if you know how to work with bash.

December 25, 2017, 14:49	Sum velocity fields over time	#1
Svensen Senior Member Join Date: Jan 2015 Posts: 150 Rep Power: 11	I have a series of time steps, i.e. t = 0; 1; 2; 3; 4. I want to create a new vector field like U_sum = U(0) + U(1) + U(2) + U(3) +U(4). Is it any way to do it using postProcess utility or ParaView ?

December 28, 2017, 17:21		#2
HakikiCanakkaleli Senior Member Canakkale Dardanelspor Join Date: Aug 2012 Posts: 135 Rep Power: 14	Hi, I haven't tested below, yet may hopefully give some ideas: 1. In Paraview, Filters -> Alphabetical -> Calculator might be a help. 2. Code: postProcess -func add <fields> might be used. In addition, Python libraries could be very useful, which I prefer over any other post-processing tools.

January 20, 2023, 06:29	any progress	#3
KingKraut Member Jo Mar Join Date: Jun 2015 Posts: 54 Rep Power: 11	Hey, did you find a solution for the problem? The add-function Object only allows the summation of different fields at the same time. I am currently looking for a tool or trying to implement it myself, which does time integration of a particular field during run time. I am quite amazed that I cannot find such a function object in the OpenFOAM-libraries. I am not sure, if I am just too blind to find ist... Anyway. I thought by finding a tool, which does additions of the same field for different times, i guess such a tool could easily be modified into a time integration function object. Of course a proper time integration function object from OpenFOAM would be something I would like much more! Thanks for any hints or suggestions!! PS: Still cant believe, such a function object does not exist yet... Edit: I would like something, that I can use during the simulation run, which is why I am looking for afunction object! Last edited by KingKraut; January 20, 2023 at 06:46. Reason: forgot some Info :-)

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January 23, 2023, 15:18		#4
Numericer New Member Join Date: Apr 2015 Posts: 15 Rep Power: 11	You can modify the solver by creating a new field that reads the previous time value of velocity and writes the sum of that value and the new velocity to the present time folder. This will be done each during each time step, so that in the end you will have sum of all velocties at all times. You can do the same without modifying the solver if you know how to work with bash.