SimScale CAE Forum

Pedestrian Wind Comfort Analysis


#1

Hi there! I’m new to SimScale, so I’m not really sure on how to use certain features. I’m trying to use the incompressible module to determine wind levels at pedestrian level in Toronto’s Financial District. I made the model, but I’m having trouble making the enclosure, it keeps on saying I have to clean up my model. I’m not sure what to clean up, and it took me quite a bit of time to make the model, so I really don’t want to scrap it. I’m also unsure of what seed face to select. What steps should I take to make the simulation? Thanks for your help!
Project link: https://www.simscale.com/projects/NLim8/pedestrian_comfort_analysis_in_financial_district/



#2

Hi @NLim8!

Let me check that and get back to you as soon as I know more!

Edit: My colleague Ajit suggested the following steps:

So there are two things we can do to avoid this:

  1. Remove the floor ( rectangular base) since this is a flat terrain model.

  2. If you click on the error face, you can see that the building has a curved face which is connected to the adjacent face of the building. We can ask the user to combine (boolean) or merge the faces of the building to be a single part and then try the enclosure.

The face in red has some error - my guess is that the red face and the adjacent face has a very small gap inbetween and the enclosure fails at this location.


Jousef


#3

Thanks for your help! I was able to make the enclosure after combining the faces of the building. Is it possible to have the enclosure as a wireframe but the geometries to show surfaces? What sort of boundary conditions would I have to set?


#4

Hi @NLim8!

These simulations can help you out in your PWC endeavour: https://www.simscale.com/projects/tags/pedestrian%20wind%20comfort/#viewMode=listView&sortBy=project_likes - you can also find other projects in the library.

For the buildings to show simply click on the eye symbol eye in the geometry tree on the right side to only hide the surrounding box faces. Let me know if that crisp explanation helped.

Jousef


#5

Thanks! I’ll have a look at those projects


#6

Hi there! I’m now trying to generate the mesh, and I’m afraid it will take too long. For 10 minutes, the mesh generation remained at 50%, so I cancelled it so that I wouldn’t waste core hours. How long would my mesh generation take, and is there a way to shorten the generation time?


#7

Hey @NLim8!

There is no rule of thumb to estimate the time it takes to finish the mesh, depends a lot on the geometry and other parameters. Start off with a (very) coarse one and work your way up while starting to implement a mesh convergence study during your simulation process to see that you won’t go too far.

Best,

Jousef


#8

I used a very coarse mesh, but it’s been staying at 50% for the last half and hour. Is this normal? Could you check my setup to see what could be causing the problem? Thanks for your help!
Project Link: [https://www.simscale.com/projects/NLim8/pedestrian_comfort_analysis_in_financial_district/ ]


#9

Yes, normal, if you are looking for something to do while you wait, you can watch the meshing log scroll by while it is seemingly stuck at 50% (for most of the meshing time) :wink:


#10

I’ve still been stuck at 50% and it’s been 140 minutes, I guess I continue to wait?


#11

Is the meshing log scrolling every minute or two or 3 … ? (only the last 1500 lines are in the meshing log at any one time)


#12

I just checked, it says it ended?


#13

That is good, now nothing happens until 100% :wink:

It will come…

Strange you only have 2511 cells though… Level 0 at that, you will likely have an empty mesh…


#14

Alright. I hope it doesn’t take too long because I’m continuing to lose core hours… Are there problems with the mesh?


#15

If you worry about core hours, and you see an obvious error like not enough cells in mesh (like this case), I would cancel it now as core hrs get eaten up between this stage and 100% and then find out why so few cells other ways…


#16

Alright, I cancelled it now. Thanks for letting me know. What went wrong with my mesh? How would I fix it for next time?


#17

While I wait for my mesh I will have a look…


#18

Thanks so much, really appreciate all your help!


#19

Geometry looks good at 100 solid bodies…

Enclosure looks OK… (EDIT Sorry I never use enclosures so I missed the actual problem that Ric has found here)

Even your refinements look OK…

I copied project and I am trying something, mesh running now, will report back…


#20

Alright, I’m glad there’s nothing wrong the geometry. Thanks!