Discussion Forum

Hello,

I have a cylinder with the transport of a dilute species (tds) and the solid mechanics module. The cylinder at some time, t, has an external pressure applied equally in all directions with geometric nonlinearity enabled. I have a probe that monitors the volume chanage (solid.J) and indeed, the volume increases as expected. The cylinder also has an initial concentration, c0, and all walls of the boundary are closed (ie. no flux). However, when the volume of the cylinder expands due to the applied pressure, the concentration does not decrease as expected (c = moles / volume) and still reads c0. This is being monitored using a domain probe with expression c (default for tds module).

Why doesn't the concentration decrease as the volume increases if the number of moles trapped in the cylinder does not change? Is there a way for concentration to take into account volume change during a simulation?

I'm currently calculating the initial number of moles and determining concentration using solid.J * initial volume of cylinder. However, at a later date, I will add more geometry elements to this model and change concentrations on the boundaries as volume increases. This could get very confusing keeping track of different concentrations.