large domain with large aspect ratio

ashkan0065 · October 23, 2020, 04:00

hello,
I have a very large domain with a very large aspect ratio. domain is a pool with a very small hole in it. pool is a cube with 10 *10*10 km and the hole diameter is 20 cm!

is there any way to simulate this type of problems without large mesh number? like scaling down or other methods?
thanks very much

lei · October 24, 2020, 18:16

Hi Ashkan, you may try to solve this problem with probably two methods:
1. use conformal mesh but gradually growing mesh size, you may try to use cut-cell mesh in ANSYS mesher;
2. a more easier way is to use interfaces between the local fine mesh region with small mesh sizes, and a broader region with large mesh sizes. Specifically to your problem, with 5 orders of magnitude change, you may need several transitions to ensure a good continuity convergence;
Other than those, is CFD really the best way to model your km domain? Or you may want to use the CFD results from the small region to provide a B.C. to the larger domain flow problem.
Hope this helps.

October 23, 2020, 04:00	large domain with large aspect ratio	#1
ashkan0065 New Member ashkan Join Date: Oct 2020 Posts: 17 Rep Power: 6	hello, I have a very large domain with a very large aspect ratio. domain is a pool with a very small hole in it. pool is a cube with 10 1010 km and the hole diameter is 20 cm! is there any way to simulate this type of problems without large mesh number? like scaling down or other methods? thanks very much

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October 24, 2020, 18:16		#2
lei New Member Lei Chen Join Date: Mar 2010 Posts: 21 Rep Power: 17	Hi Ashkan, you may try to solve this problem with probably two methods: 1. use conformal mesh but gradually growing mesh size, you may try to use cut-cell mesh in ANSYS mesher; 2. a more easier way is to use interfaces between the local fine mesh region with small mesh sizes, and a broader region with large mesh sizes. Specifically to your problem, with 5 orders of magnitude change, you may need several transitions to ensure a good continuity convergence; Other than those, is CFD really the best way to model your km domain? Or you may want to use the CFD results from the small region to provide a B.C. to the larger domain flow problem. Hope this helps.