Changing the length scale of a mesh

[mangerij]

Hi,

I am wondering if something is possible.

Say I have a mesh, whose solution has some length scale that is on the order of nanometers. So let's say the mesh is 3.0x3.0x3.0 nanometers with element size of 1 nm.

If I wanted to load this solution into a new calculation but rescale the lengths of the mesh to micrometers, 0.003x0.003x0.003 µm with an element size of 0.001 µm, is there an easy way of doing this?

John

[mangerij]

(besides rescaling my units in my equations by the way )

[YaqiWang]

How do you load the solution?

[mangerij]

Just as an initial condition: file = out.e in [Mesh] and then initial_from_file_var = var as an initial condition. Would be great if there was something like rescale = 0.001 in [Mesh] to redefine the length coordinates in the out file but keeping solution variables. Thought i'd check if something like that existed

…

________________________________ From: Yaqi <[email protected]> Sent: Thursday, November 19, 2020 4:56 PM To: idaholab/moose <[email protected]> Cc: Mangeri, John <[email protected]>; Author <[email protected]> Subject: Re: [idaholab/moose] Changing the length scale of a mesh (#16251) *Message sent from a system outside of UConn.* How do you load the solution? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fidaholab%2Fmoose%2Fdiscussions%2F16251%23discussioncomment-133763&data=04%7C01%7Cjohn.mangeri%40uconn.edu%7Cba28f5f11672485a904008d88ca3a2ab%7C17f1a87e2a254eaab9df9d439034b080%7C0%7C0%7C637413981721930034%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=yk28si%2FzwgC8%2Bu0Ugb6ueHEsqJ5zlCSBCjZ%2B2%2B5AeCM%3D&reserved=0>, or unsubscribe<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fnotifications%2Funsubscribe-auth%2FABZ65FBRT3RFD3NWKVE4HUTSQU5ZVANCNFSM4T3OHQNA&data=04%7C01%7Cjohn.mangeri%40uconn.edu%7Cba28f5f11672485a904008d88ca3a2ab%7C17f1a87e2a254eaab9df9d439034b080%7C0%7C0%7C637413981721940029%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=fmkH7kHW8bPyNKl6tsPewI6DedsKRXg5lO6p6YYfdyw%3D&reserved=0>.

[aeslaughter]

I think this can do what you need: https://mooseframework.inl.gov/source/meshgenerators/TransformGenerator.html

test/tests/meshgenerators/transform_generator/rotate_and_scale.i

[YaqiWang]

Maybe do this initial_from_file_var to a different variable and then add an IC to use that variable to initialize the target variable with a scaling factor in the input?

[aeslaughter]

Another thing to try is the SolutionUserObject, it has a scale option as well. This can be used with SolutionFunction for the IC I believe. It might take both the TransformGenerator and the SolutionUserObject. Good luck.

[mangerij]

TransfromGenerator looks to be it. Thanks! This might be very helpful in the near term.

[vincentlaboure]

I am guessing this approach would not be enough if the field you are trying to restart has units that contain length (e.g., a flux).