Unsteady staggered DPM injections
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Unsteady DPM injection will release particles at the beginning of every timestep. If the timestep size is very small and the elapsed time of the simulation is long, this will result in a large number of particle packets which are tracked in the domain. This is expensive in CPU time. A workaround is to write a UDF which will stagger the particle injection. Instead of releasing the particles at the beginning of every timestep, the injections will be staggered at every user specifed time-interval. This can be done by moving the unsteady-starting-time of the injection forward by this user specified time after an injection has just been performed. During the non-injection timestep, the UDF will also accumulate the mass of the particles and will release the accumulated mass all together at the next injection event. In this way, the total mass of the particles in the domain is preserved. As a sample problem, an unsteady silo launch is used. The particles are injected at the moving nozzle exhaust boundary. The UDF, sample problem, presentation, and animations are provided. The files are attached to this solution. <a target=_blank href="http://www.fluentusers.com/support/solutions/1017/dpm-inject.zip">http://www.fluentusers.com/support/solutions/1017/dpm-inject.zip</a>http://www.fluentusers.com/support/solutions/1017/dpm-inject.zip |
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