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Comsol 5.3 ODE Explicit Solver Problem
Posted 06.11.2017, 13:02 GMT-5 0 Replies
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Last year I inquired about a problem related to particle tracking in a stationary magnetic field - see https://www.comsol.com/forum/thread/123312/energy-conservation-for-relativistic-particle-tracing-in-magnetic-field-problem?last=2016-09-13T15:52:27Z
The problem I was having was that the particle energy was not conserved in the simulation while it must be perfectly conserved from the physics point of view. I was given a very good advice to switch to an RK solver, specifically the Dormand-Prince 5 type. After that, the situation with energy conservation was dramatically improved.
That was while using Comsol 5.2a. When I recently upgraded to Comsol 5.3., running the same problem produced this following error message : " Mass matrix may depend on solution or time. Reformulate the equation or use an implicit solver."
However, switching back to an implicit solver does remove the error but again, it introduces a gross energy non-conservation which was the whole point of switching to Dormand-Prince.
I am attaching one of the setups (meshes and solutions cleared).
Thank you, Gennady
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Hello Gennady Fiksel
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