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  1. Dec 03, 2015
  2. Oct 19, 2015
  3. Aug 26, 2015
  4. Jul 19, 2015
  5. Jun 26, 2015
    • Henry Weller's avatar
      reactingTwoPhaseEulerFoam: Added experimental run-time selectable LTS support · e0d7809c
      Henry Weller authored
      Select LTS via the ddtScheme:
      
          ddtSchemes
          {
              default         localEuler rDeltaT;
          }
      
      The LTS algorithm is currently controlled with the standard settings in
      controlDict, e.g.:
      
          maxCo           0.5;
          maxDeltaT       2e-8;
      
      with the addition of the optional rDeltaT smoothing coefficient:
      
          rDeltaTSmoothingCoeff 0.02;
      
      which defaults to 0.02.
      
          ddtSchemes
          {
              default         localEuler rDeltaT;
          }
      e0d7809c
  6. Jun 25, 2015
  7. Jun 12, 2015
    • Henry Weller's avatar
      reactingTwoPhaseEulerFoam: New twoPhaseEulerFoam supporting mass-transfer and reactions · 3ed90ae7
      Henry Weller authored
      Multi-species, mass-transfer and reaction support and multi-phase
      structure provided by William Bainbridge.
      
      Integration of the latest p-U and face-p_U algorithms with William's
      multi-phase structure is not quite complete due to design
      incompatibilities which needs further development.  However the
      integration of the functionality is complete.
      
      The results of the tutorials are not exactly the same for the
      twoPhaseEulerFoam and reactingTwoPhaseEulerFoam solvers but are very
      similar.  Further analysis in needed to ensure these differences are
      physical or to resolve them; in the meantime the twoPhaseEulerFoam
      solver will be maintained.
      3ed90ae7
    • Henry Weller's avatar
      twoPhaseEulerFoam: Minor reorganization · b5edc2c9
      Henry Weller authored
      b5edc2c9
  8. May 29, 2015
    • Henry's avatar
      MRF: Separate MRF from fvOptions · 2b9a2adf
      Henry authored
      fvOptions does not have the appropriate structure to support MRF as it
      is based on option selection by user-specified fields whereas MRF MUST
      be applied to all velocity fields in the particular solver.  A
      consequence of the particular design choices in fvOptions made it
      difficult to support MRF for multiphase and it is easier to support
      frame-related and field related options separately.
      
      Currently the MRF functionality provided supports only rotations but
      the structure will be generalized to support other frame motions
      including linear acceleration, SRF rotation and 6DoF which will be
      run-time selectable.
      2b9a2adf
  9. Apr 28, 2015
  10. Apr 27, 2015
    • Henry's avatar
      twoPhaseEulerFoam: Added experimental face-based momentum equation formulation · 16f03f8a
      Henry authored
      This formulation provides C-grid like pressure-flux staggering on an
      unstructured mesh which is hugely beneficial for Euler-Euler multiphase
      equations as it allows for all forces to be treated in a consistent
      manner on the cell-faces which provides better balance, stability and
      accuracy.  However, to achieve face-force consistency the momentum
      transport terms must be interpolated to the faces reducing accuracy of
      this part of the system but this is offset by the increase in accuracy
      of the force-balance.
      
      Currently it is not clear if this face-based momentum equation
      formulation is preferable for all Euler-Euler simulations so I have
      included it on a switch to allow evaluation and comparison with the
      previous cell-based formulation.  To try the new algorithm simply switch
      it on, e.g.:
      
      PIMPLE
      {
          nOuterCorrectors 3;
          nCorrectors      1;
          nNonOrthogonalCorrectors 0;
          faceMomentum     yes;
      }
      
      It is proving particularly good for bubbly flows, eliminating the
      staggering patterns often seen in the air velocity field with the
      previous algorithm, removing other spurious numerical artifacts in the
      velocity fields and improving stability and allowing larger time-steps
      For particle-gas flows the advantage is noticeable but not nearly as
      pronounced as in the bubbly flow cases.
      
      Please test the new algorithm on your cases and provide feedback.
      
      Henry G. Weller
      CFD Direct
      16f03f8a
  11. Apr 12, 2015
  12. Apr 11, 2015
  13. Apr 08, 2015
  14. Apr 05, 2015
    • Henry's avatar
      twoPhaseEulerFoam: Add partial-elimination to phase flux and velocity correction · a6dded3b
      Henry authored
      Improves stability and convergence of systems in which drag dominates
      e.g. small particles in high-speed gas flow.
      
      Additionally a new ddtPhiCorr strategy is included in which correction
      is applied only where the phases are nearly pure.  This reduces
      staggering patters near the free-surface of bubble-column simulations.
      a6dded3b
  15. Mar 17, 2015
  16. Feb 12, 2015
  17. Feb 09, 2015
  18. Dec 10, 2014