Selman, You define the time sampling with the "SampleFrequency" flag. Also, you can define output frequency with the "OutputFrequency" flag. Here it is an example: <FILTER TYPE="ReynoldsStresses"> <PARAM NAME="OutputFile"> MyAverageField </PARAM> <PARAM NAME="RestartFile">MyAverageRst.fld</PARAM> <!-- In case you have a previous average --> <PARAM NAME="OutputFrequency"> 100*TimeStep </PARAM> <PARAM NAME="SampleFrequency"> 50 </PARAM> </FILTER> It will output the file each 100 time steps in order to check convergence and it will use data each 50 time steps to compute the averages. Em sáb., 24 de ago. de 2024 às 07:54, Selman BAYSAL < selmanbaysal@comu.edu.tr> escreveu:

Hello David,

I'm doing well, thank you! I really appreciate your quick response. I have been trying to define another boundary by using GMSH, however, I believe that using boolean operators will be the most suitable approach for my problem.

As you mentioned, the User Guide states that the "Reynolds stress" filter provides time-averaged values. However, I couldn't find a clear statement in the document about which time intervals are used. My assumption is that it utilizes the TimeStep value defined in the XML file. Still, to be certain, I would greatly appreciate it if someone with different opinion or knowledge could share their experince on this matter.

Thank you once again for your time and attention! I wish you all the best in your work!

Regards,

Selman Baysal R. A. in Hydraulics Dept. of Civil Eng'g Çanakkale Onsekiz Mart University -- ITU Civil Eng., BSc. ITU Coastal Sci. & Eng., MSc. ------------------------------ *Kimden:* ribeiro.danielg@gmail.com; *Kime:* selmanbaysal@comu.edu.tr; - 23/08/24 - 14:42 *Bilgi:* nektar-users@imperial.ac.uk; *Konu:* Re: [Nektar-users] Introducing a Fluid Jet into the Quasi-3D IncNavierStokesSolver and Reynolds Stresses Filter

Hello Selman, how are you?

i. I think you could do that with your boundary condition on the wall, simply implementing the value of the velocity on the specific component. Also, you can use boolean operators to limit the region and also time to specify the period. There is (or are) an explanation of that in the user guide. Also, If it's not on the boundary, you could use a body force, also using boolean operators and a time flag for the specific period.

ii. The Reynolds stress filter will compute the time average of your solution as well as the time-averaged Reynolds stresses. If you compare the results obtained from it with the ones from a history file, they will eventually be the same, but as the average process is different for the filter, they differ for short average periods. At least that was my experience with it.

I hope it helps and I wish you luck,

Daniel.

Em sex., 23 de ago. de 2024 às 07:15, Selman BAYSAL < selmanbaysal@comu.edu.tr> escreveu:

...

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Dear All,

I have two different questions that I would greatly appreciate your insights on:

1. I'm currently investigating the laminar-to-turbulent transition in oscillatory wave boundary layers. For some time, I have been using a roughness element to generate initial perturbations. However, I would like to find out how to define a fluid jet (i.e., vertical velocity v = A where A is a constant) that puffs puffing for a while (e.g., from t0 to t1) from a specific point at the bed (e.g., x=y=z=0 at the boundary "2"). Is it possible to implement this in Quasi-3D approach? 2. I have implemented "Reynolds stresses" filter into my XML code and obtained output files without any problem. However, when I compared these output files with the original checkpoint file (*.chk), I observed noticeable discrepancies in the velocity and pressure variables. The raises concern about the accuracy of other variables such as uu, uv, vw, etc. Could you please clarify what exactly this filter outputs?

Thank you very much for your time and intention. Any advice or recommendations you can provide would be greatly appreciated!

Best regards,

Selman Baysal R. A. in Hydraulics Dept. of Civil Eng'g Çanakkale Onsekiz Mart University -- ITU Civil Eng., BSc. ITU Coastal Sci. & Eng., MSc. _______________________________________________ Nektar-users mailing list Nektar-users@imperial.ac.uk https://mailman.ic.ac.uk/mailman/listinfo/nektar-users