News

Nogrid points release 6.6.1

May 2019

The release of  NOGRID points 6.6.0 and 6.6.1 is available now.

This is new:

Nogrid Solver 6.6.1

  • Fixed: Thermal contact between chambers was disabled.
  • Fixed: A library was not installed correctly.

Nogrid Solver 6.6.0

  • New: A mass conservative method based on the Gradient Smoothing Method (GSM) was added. Based on a background mesh, Finite Volume operators are created and used for the solution of continuity equation, while the momentum equations are still solved using Moving Least Squares operators. The GSM is implemented for simulations without a free surface and can be used for LAGRANGE and EULER scheme for the coupled (vp-) solver without a rotational or mirror symmetry or periodic boundary conditions.
  • Optimization: Performance of "geometrical adaptive finite point density (H_adaptGeo)" was increased by revision of the temporal and spatial gradient of the finite point density. Especially large complex geometries which needed a large set of H_modifiers to run in an acceptable time can now be simulated with H_adaptGeo without any performance regression.
  • New: A new radiation model for the computation of the radiative heat transfer within a semi-transparent solid or fluid is implemented. The name is Hybrid-P1 model and the basic idea of this Hybrid-P1 model is to subdivide the transmission spectrum into spectral bands with approximately constant absorption in each band. "Transparent" bands with small optical thickness and "opaque" bands with large optical thickness are distinguished and computed separately. Please refer to theory for more details.
  • New: The displacement of degenerated bubbles can be set to zero.
    If bubbles become degenerated the fall-back pressure boundary condition might result in disappearance of the bubbles. Especially bubbles touching a wall are an important result of simulations. A way to keep these bubbles is to "freeze" them, i.e. to set the displacement of bubble points to zero. See BND_free_bubble for details.
  • New: Remove underresolved gaps from bubble algorithm.
    The bubble code collects unwetted (inactive) points if the distance between the points is lower than one smoothing length. If a gap is not filled, the inactive gap points act as connection of the bubbles beside the gap. Especially if a gap has the shape of a wedge, there will always remain inactive points which act as connection for adjacent bubbles. In reality the wedge would be filled completely and no connection of the bubbles would be present. To avoid this nonphysical behavior, points belonging to underresolved gaps are automatically detected and excluded from the gap algorithm.
  • New: If CHAMBER_pressure is present %TOUCH_solid% takes it into account now. The normal stress on the wall is compared to chamber pressure to decide whether to detach. Before, it was always compared to zero pressure.
  • Bugfix: The sign of the source term for CODI_Q in case of using the integration method CODI_stationary has been fixed.

 

Nogrid points GUI (Graphical User Interface)

  • The material properties dialog was re-designed and the new material properties were added to the GUI and to the syntax parser.
  • An example for the new radiation model "hybrid P1" was added to the example database.
  • A FSI (Fluid Structure Interaction) case was added to the example database.

 

Nogrid pre-processor Compass

  • Face meshing was improved:
    1) If meshing of a certain face should fail a better fall back meshing was implemented.
    2) In case edges of a face are small compared to the mesh size the new algorithm will merge these edge to a longer edge. As a result the mesh quality is more uniform.
  • New: A face healing feature was added. The User can specify a tolerance distance in which a face is repaired or re-computed.