swirl flow—fluent常见问题.docVIP

The Single Reference Frame (MRF) Model Solution Strategies for a Rotating Reference Frame:  (Segregated solver only) Consider switching the frame in which velocities are solved by changing the velocity formulation setting in the Solver panel. (See Section 10.2.5: Choosing the Relative or Absolute Velocity Formulation for details.)  (Segregated solver only) Use the PRESTO! scheme, which is well-suited for the steep pressure gradients involved in rotating flows.  Ensure that the mesh is sufficiently refined to resolve large gradients in pressure and swirl velocity.  (Segregated solver only) Reduce the under-relaxation factors for the velocities, perhaps to 0.3{0.5 or lower, if necessary.  Begin the calculations using a low rotational speed, increasing the rotational speed gradually in order to reach the final desired operating condition (see below). The Multiple Reference Frame (MRF) Model(is recommended for steady state) limits:  Use of the realizable k-e model with multiple reference frames is not recommended.  Strictly speaking, the use of multiple reference frames is meaningful only for steady flow. However, FLUENT will allow you to solve an unsteady flow when multiple reference frames are being used. In this case, You should carefully consider whether this will yield meaningful results for your application.  Particle trajectories and pathlines drawn by FLUENT use the velocity relative to the cell zone motion. For massless particles, the resulting pathlines follow the streamlines based on relative velocity and are meaningful. For particles with mass, however, the particle tracks displayed are meaningless. Similarly, coupled discretephase calculations are meaningless. An alternative approach for particle tracking and coupled discrete-phase calculations with multiple reference frames is to track particles based on absolute velocity instead of relative velocity. To make this change, use the define/models/dpm/options/track-in-absolute-frame text com