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Restart simulation with particles already in the domain
Posted 13 mar 2012, 12:14 GMT-4 Charged Particle Tracing, Fluid & Heat, Computational Fluid Dynamics (CFD), Particle Tracing for Fluid Flow, Studies & Solvers Version 4.2a, Version 5.3 4 Replies
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I have another question regarding the particle tracing module. I have a model consisting of a Laminar Flow (chns) and a Particle Tracing for Fluid Flow (fpt) interfaces. Assume that I solve first the fluid flow without solving for the particles’ position and that my inlet flow rate is periodic (let’s say with period is one second). I then introduce on the inlet a distribution of particles that are released every 0.1 s and I run the particle tracing for one period. My problem comes when I want to restart the simulation for the particle tracing in order to calculate the fate of the particles during the next 1 second – now I have the particles that were already in the domain at the end of the previous calculation plus the ones that are released every 0.1 s during this new calculation. I cannot figure out how to do that, simply saying to the solver to use as initial condition the previous solution gives an error in the stiffness matrix.
Anyone has an idea?
Thanks in advance, J
Hello J
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Steven Conrad, MD PhD
LSU Health
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1. The most flexible is to export the particle positions from the end of the first study, then use the "Release from Data File" option to set the initial positions for the second study. This also allows you to specify a different initial velocity.
2. You can also "trick" the solver into using the final particle position and velocity as the initial condition for a second study. An example is attached (made in V5.3). The basic steps are:
* Set up the model and compute the first study as you would do normally.
* Add a second study, and set the "Initial values of variables solved for" to come from Study 1.
* In the list of Times, set the initial time to correspond to the exact end time of Study 1.
This last step tricks the particle release mechanism into using the final position and velocity from Study 1 in Study 2.
Dan
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Dan
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Steven Conrad, MD PhD
LSU Health