Timeline for Conservation of Mass in 1D Advection-Diffusion Equation
Current License: CC BY-SA 3.0
4 events
| when toggle format | what | by | license | comment | |
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| Jan 24, 2014 at 0:12 | comment | added | boyfarrell | @tom figured it out! It's because a Neumann BC applied to the advection-diffusion equation only constrains the diffusion part of the flux; the boundary remains open to the advection component. See here, scicomp.stackexchange.com/questions/10407/… | |
| Dec 11, 2013 at 6:18 | comment | added | boyfarrell | Actually I still don't understand why mass leaves the system in the final figure. The boundary conditions should prevent it, right? When I do the same simulation with the FVM I get conservation, see here scicomp.stackexchange.com/questions/7736/… Also note if you use trapezium rule to keep track of your mass you will see it continually change. With the FVM, where you use discretised the integral equations, you can so a simple sum to count the mass. Notice it stays exactly the same over time. | |
| Dec 11, 2013 at 5:54 | comment | added | tom | Thanks for that, I've actually done a very similar thing, but I'm losing mass. I'm in a very similar situation to yourself here: scicomp.stackexchange.com/questions/5434/… Did you manage to resolve your troubles by changing your BC's? BTW, your notes are fantastic, I'll definitely try FVM sometme | |
| Dec 11, 2013 at 5:13 | history | answered | boyfarrell | CC BY-SA 3.0 |