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Topics - stan_lw

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Wind Engineering (WE-UQ) / Unable to select pimpleFoam in WE-UQ
« on: October 21, 2021, 04:56:06 AM »
The Documentation ( states that we can choose pisoFoam, icoFoam or pimpleFoam, but at the EVT Solver drop-down list, I can only choose either pisoFoam or icoFoam (see attached screenshot). How do we select "pimpleFoam" instead of "pisoFoam"? Thank you.

Wind Engineering (WE-UQ) / Selecting version of OpenFOAM in WE-UQ
« on: October 21, 2021, 04:51:28 AM »
Hi, I understand from the Documentation that WE-UQ has OpenFOAM v6 and v7. I run a test case, from the pisoFoam.log file, the line “/home1/apps/intel18/impi18_0/OpenFOAM/OpenFOAM-6.0/platforms/linux64IccDPInt32Opt/bin/pisoFoam -parallel” indicates that OpenFoam version 6 is used. How do I set the version of OpenFoam to v7 in WE-UQ? Thank you.

Wind Engineering (WE-UQ) / TInFFoam freezes at first time step
« on: May 02, 2021, 01:59:53 AM »
I tried running the homogeneous tutorial case with turbulentDFSEMInlet. At the first time step, the output is as follow:

Starting time loop
Time = 0.025
Patch: inlet eddy box:
    volume    :4
    maxSigmaX    : 0.5

The simulation freezes after displaying the above message, with no further output. I will send the case file through email, thanks.

Hi, I tried to run the homogeneousTurbulence tutorial case with the turbulentDFSEMInlet boundary condition but the simulation cannot start with a missing keyword "delta". What is this delta? I cannot find it in the documentation. I will email the case file as it failed to upload here, thanks.

Wind Engineering (WE-UQ) / Filter factor in Digital Filtering Method
« on: February 22, 2021, 08:37:07 PM »
I have a question regarding the filter factor for the Digital Filtering Method. If I correctly understood the theory Section 1.3 (please correct me if I am wrong), N is the filter width and n is a ratio between a length scale L and grid spacing Δx, i.e., n = L/Δx. It is also mentioned that N should be chosen such that N ≥ 2n. However, in Section 2.2, Table 2.2 specifies that the filterFactor entry should be ≥ 4, i.e., N/n ≥ 4 or N ≥ 4n. Any reason why you implement a larger filter factor (N/n ≥ 4) than required by the theory (N/n≥ 2)?

Also, I think there is a typo regarding the definition of n, where n should be L/Δx (unit-less) instead of LΔx (unit of meter squared) in the documentation.

For the gridFactor, I use the default value (=1). For my inlet grid, the smallest grid area is 7.8125e-5 m^2. From the documentation “gridFactor entry defines ratio between the virtual grid spacing Δ with the square root of the area of the smallest face element on the inflow plane”, the virtual grid spacing Δ would be square root of 7.8125e-5 ~ 0.0088 m. Since my inlet plane is 4 m by 3 m, I expect there will be 4/0.0088 = 454 grids in the y-direction and 3/0.0088 = 341 grids in the z-direction, meaning there will be 454*341=154814 grids in the virtual grid. However, when I run pisoFoam, the output states “Generating Inflow for 25440 faces”. Does this mean there are only 25440 grids in the virtual grid? Is it possible to view the virtual grid, or output the coordinates of the virtual grids generated by TInF? Thank you.

I am trying to run a test case with turbulentDFMInlet using tabulated boundary data for U, R, L. Since the inhomogenousTurbulence case in the tutorial uses tabulated boundary data, I started with that case. This tutorial case uses turbulentATSMInlet, and I encounter no issue with that. However, when I modified it to run with turbulentDFMInlet, it crashed after the first time step. Below are the three changes I made to the original tutorial case file:

1)   In directory /constant/boundaryData/inlet, I renamed the file “L” to “L_ATSM”, then renamed “L_copy” to “L”
2)   In directory /0/U, I changed the inlet boundary condition from turbulentATSMInlet to turbulentDFMInlet
3)   Change endTime from 20 to 2 in controlDict file (this is not crucial, just to reduce the total run time while troubleshooting)

The case file is too large to be uploaded here. I will send it over email. The zipped case file also contains the run.log file and the error message when it crashed. Thank you!

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