SimScale CAE Forum

Creating Mesh of Landscape


#1

Hey, I have problems creating a mesh of this file. Maybe there is not enough power to create it ?
I am asking myself also if this is the most realistic way to simulate the effect of hilly topography on windstreams in this scale ? Thanks for your advice

https://www.simscale.com/workbench/?pid=2480970509533460954&mi=spec%3A817f1cc6-98c6-42cc-8c8c-d622464fca5e%2Cservice%3AMESHING%2Cstrategy%3A14&sh=4

I also tried the same only with the surface of the landscape and the cartesian boy outside the geometry and it worked, but its not really what i want for the simulation. Sry, deleted the example.


#2

here a screenshot


#3

With surface was possible, but with warning ???


#4

Hi @tbaeumer

Initially you had an issue with your base being a sheet with no thickness. It looks like you understood the problem and fixed it by adding a base. Take note that if you want to simulate the wind flow around the landscape topography you need a mesh of the air volume around the landscape, not the landscape itself. To do this, go to geometries, click on the drop down menu on the right of your geometry and under ‘add geometry operation’, choose enclosure. This enables you to form a mesh of the air around the landscape. There are several tutorials on the website which include use of the enclosure function, I’ve linked one of them below.

https://www.simscale.com/docs/tutorials/natural-convection/

Now for the bad news; your geometry is extremely complicated because of all the tiny features with small radii and so you lack the RAM to even mesh this geometry. You can get more RAM by choosing a higher number of processors but unless you are a professional user, 16 is the maximum. To be honest, I am not even sure if the full 96 cores would be enough for this truly complex geometry. You would have to greatly simply your model, ironing out all of the small features, to have a chance of solving it.


#5

Hey @roy_g

Great, I think thats helps a lot already, i could create a mesh with it and now i run the simulation. I am also not sure about how big to choose the boundary in this enclosure thing to get it realistic. Finally I dont want to have only one inflow face and one pressure outlet, so I try to work vith cvv clima data. Do you know a good example working like this ? Would be very helpful

I thought this could be a problem, I am working with Rhino and i already simplyfied the model with draping it the most rough way. Dont know really how to simplify it more. I also dont want to loose the topography.


#6

Do you men CSV? As in to upload a file with the boundary condition data inside? I’ve never tried but I’ve used the table before, which is fine when you don’t have too many data point. If you need to use CSV, perhaps someone else will explain to you the required layout for the file. The link below has some information but i’m not sure if its enough

https://www.simscale.com/docs/content/simulation/model/boundaryConditionTypes/OF_new_velocity_inlet.html

You are correct that you need your enclosure to stretch further than the topography. In your case this is important for the outlet so that the outlet condition does not effect your results. Most of my simulations are with internal flows (e.g. flow in a pipe) and so a certain distance is required before the model on the inlet side because it takes time for the velocity profile to build up in the pipe (once it builds up it is called a developed flow). However, since your model is an open flow around an object I think you do not need any extra air region before your model only after it (as I explained above). On this topic, make sure that your wall boundary conditions around the air volume are set to ‘slip’ rather than ‘no slip’ as the latter is for fluids that are constrained by a solid such as in a pipe.


#7

Hi @tbaeumer,

With regards to Roy’s comments.

This link might help.

Cheers.

Regards,
Barry


#8

Thanks. Seems very complicated. I will see how i get through this