Rick's Blog
OpenFOAM Baby Steps - Chapter 2: Cavity Flow, Part 2
My short attention span got bored with all the paraFoam changes in the Cavity Flow tutorial. So we rejoin that, halfway through...
DISCLAIMER:
This is not intended as a tutorial. This is my process for working through the available documentation in a manner that makes sense to me. Feel free to follow along, but realize that I am interpreting documentation that already exists.
Picking up at paragraph 2.1.4.5, the streamline plot was very straightforward (once I learned to pay attention to what was selected in the Pipeline Browser!).
Starting with paragraph 2.1.5, the focus is on creating the same case with a finer mesh. Working according to the script, everything went fine. I tried to add simpleGrading to the finer mesh (because I'm 'helping') only get a gentle reminder to keep an eye on the Courant number. Running icoFoam generated an error telling me the Courant number was greater than 1, and maybe I shouldn't be such a dufus! (The second part may have been my inner monologue.)
The section on plotting worked as advertised. Hopefully there will be a more in-depth look about the postProcess command. That seems like something that is only intuitive once you know what you want. Once post-processed, the plotting functions did seem fairly intuitive.
Fun Fact
I found the camera icon at the top of any of the view windows in paraView which will write that view to an image file. Holding SHIFT, CTRL or ALT while clicking will write it to the clipboard! A word of caution: it will capture exactly as it looks on-screen, so if you have windows with odd aspect ratios to maximize screen real estate, you probably want to temporarily adjust that before capturing.
Paragraph 2.1.6 for creating a graded mesh was straight-forward. It took me some time to step through the numbering convention for faces and calculating the time step. Once those details were taken care of, running the cases was trivial. If the GIF to the right works (Edit: It turns out the GIF does not work on most browsers. ), you can see practically identical results between the fine and graded cases. Obviously, the computational savings for cases with large numbers of cells could be significant.
My attention span is once again used up. Next time we will start with 2.1.7 and adjusting Reynolds numbers!
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