Marina,
In the absence of more detailed information, I'm not sure I'm understanding your problem correctly, but here are a few items that may be relevant:
1) The variable(s) for which you are solving the convection-diffusion problem must be solved for throughout the entire simulation over the entire domain where they may be needed. You can't toggle them on or off during the simulation unless you know beforehand the times at which they must be turned on or off.
2) The convection and diffusion terms can be turned off (or made extremely small) using a smoothed step function, where the step occurs at the damage threshold.
3) Making the convection-diffusion process contingent on the distance to an arbitrarily located damage location is trickier, but it can be done. Either a non-local coupling must be used or a dependent variable must be created to solve for the locations that are affected by nearby damage.
--
Luke Gritter
AltaSim Technologies
In the absence of more detailed information, I'm not sure I'm understanding your problem correctly, but here are a few items that may be relevant:
1) The variable(s) for which you are solving the convection-diffusion problem must be solved for throughout the entire simulation over the entire domain where they may be needed. You can't toggle them on or off during the simulation unless you know beforehand the times at which they must be turned on or off.
2) The convection and diffusion terms can be turned off (or made extremely small) using a smoothed step function, where the step occurs at the damage threshold.
3) Making the convection-diffusion process contingent on the distance to an arbitrarily located damage location is trickier, but it can be done. Either a non-local coupling must be used or a dependent variable must be created to solve for the locations that are affected by nearby damage.
--
Luke Gritter
AltaSim Technologies
