Search found 3889 matches

by raback
23 Jan 2021, 23:14
Forum: General
Topic: unitialized time step size
Replies: 3
Views: 20

Re: unitialized time step size

Hi Why can you not initialize the "deltaT" in "initial condition" section? Sometimes the timestep size may be difficult to set if it depends on the time itself. So if we have a function dt_i=f(t_i)=f(t_{i-1}+dt_i) Usually this would be rather smooth function and solvable with fix...
by raback
22 Jan 2021, 23:22
Forum: ElmerGUI
Topic: ElmerGUI tutorials updated - user input requested
Replies: 0
Views: 20

ElmerGUI tutorials updated - user input requested

Hi Rich has been graciously fixing, correcting and updating the ElmerGUI tutorials and related files in a true spirit of open source, see https://github.com/ElmerCSC/elmerfem-manuals These are now also available as pdf and zip files in https://www.nic.funet.fi/pub/sci/physics/elmer/doc/ It would be ...
by raback
22 Jan 2021, 20:40
Forum: ElmerSolver
Topic: Current in PCB trace -> temperature rising
Replies: 5
Views: 29

Re: Current in PCB trace -> temperature rising

Hi Yes, the unit for heat source should be W.m^(-3) and the rho*i^2 should be consistent with that. Is the current density formula i=I/A not rather limited to simple geometries? This is the reason why typically we see workflows where the current density is computed from a differential equation. Ther...
by raback
22 Jan 2021, 12:48
Forum: ElmerSolver
Topic: Current in PCB trace -> temperature rising
Replies: 5
Views: 29

Re: Current in PCB trace -> temperature rising

Hi

If you know the current density, i, as a field and the electric resistivity, rho, can you not just use "Heat Source" that is "rho*i^2"?

-Peter
by raback
22 Jan 2021, 11:04
Forum: General
Topic: How to save data on disk at given time
Replies: 3
Views: 30

Re: How to save data on disk at given time

Hi

For any solver you should be able to device a keyword

Code: Select all

  Exec Condition = Real 
that can be a function of the global variables (time, timestep size,...). The solver is executed only when the values is greater than 0.

-Peter
by raback
20 Jan 2021, 18:51
Forum: ElmerSolver
Topic: About how-to set surface tension in Level Set Method
Replies: 7
Views: 140

Re: About how-to set surface tension in Level Set Method

Hi There is no "surface tension coefficient" since you don't have a surface in levelset. Instead the surface is smeared down and the surface tension becomes a force of type c\grad{d}. This is communicated to the Navier-Stokes equation by the following way: Potential Force = Logical True Po...
by raback
20 Jan 2021, 18:21
Forum: ElmerSolver
Topic: Infinite Element Domain for Whitney AV solver
Replies: 2
Views: 50

Re: Infinite Element Domain for Whitney AV solver

Hi You cannot enforce the vector potential in the normal direction. The reason is that the vector potential is spanned by the basis functions defined on the edges. And on the boundary all edges are by construction tangential. So you can only set the tangential component to zero, "AV {e} = 0&quo...
by raback
20 Jan 2021, 10:58
Forum: General
Topic: Heat Balance Check Elmer Radiation Problem
Replies: 1
Views: 61

Re: Heat Balance Check Elmer Radiation Problem

Hi Perhaps you can use FluxSolver to compute the heat fluxes on the solid parts. Or you could use "Calculate Loads" to get the nodal heat flux. Unfortunately there is no postprocessing features currently that would allow for separation of different fluxes from the various BCs. However, if ...
by raback
18 Jan 2021, 15:25
Forum: ElmerSolver
Topic: restart and result file
Replies: 2
Views: 38

Re: restart and result file

Try with

Code: Select all

Simulation 
  ...
  Output Intervals = 0
  Output Variable 1 = displacement 1 
  Output Variable 2 = displacement 2
by raback
15 Jan 2021, 18:02
Forum: ElmerPost
Topic: Nodes grouped with regard to geometry and boundaries
Replies: 3
Views: 76

Re: Nodes grouped with regard to geometry and boundaries

Hi Mateusz,

Perhaps you could share the sif for those facing the same challenge in the future.

-Peter