Transient or steady flow?

- September 21, 2018 at 10:17 am
  
  seth_iskandar
  Subscriber
  
  Hi,
  
  I'm currently trying to simulate a multiphase flow with particles diameter of 10 cm. Macroscopic Particle Modelling (MPM) is used since the particles are much bigger than the maximum cell size and shouldn't be treated as mass points, small granules etc.
  
  In user's guide it is stated that transient solver should be selected for most cases except for cemented particles simulations. I've tried steady-state simulation but the macroscopic particles seem not to be injected at all. My questions regarding this:
  
  - What is a cemented particle in the sense of MPM?
  
  - Why the simulation should be carried in transient-state?
- September 21, 2018 at 4:08 pm
  
  jmccasli
  Ansys Employee
  
  Hi seth_iskandar,
  
  The MPM does Lagrangian tracking of particles through the domain that are larger than the scale of the mesh. This is a transient process and thus must be simulated as transient.
  
  The one exception is if the particles are not moving at all (i.e., there location is fixed in space). This is what is meant by "cemented" particles. You can choose the option under the injection panel as shown below:
  
  Regards,
  
  Jeremy