Engrid OpenFOAM Stammtisch Stuttgart2009

ENGRID: Open-Source Mesh Generation

enGits GmbHMarie-Curie-Straße 8

79539 Lörrach Deutschland / Germany / Allemagne

www.engits.cominfo@engits.com

OpenFOAM “Stammtisch”

Thursday, November 5, 2009

University of Stuttgart, Campus Vaihingen

Allmandring 30, 70569 Stuttgart

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 2

OverviewOverview

• Where are we now

– Brief introduction

– Demonstration

– Examples

• Future

– What is planned?

– What is envisaged?

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 3

Motivation for Open-Source MeshingMotivation for Open-Source Meshing

• enGits started in October 2006

– Main activity: software development for very specific CFD problems

– To extend business a reliable CFD solution was desired

• Commercial codes too expensive

(no guaranteed business coming in)

• Open-source, as well as in-house, solver and post-processing available

• Meshing situation not sufficient for commercial CFD work

• Expertise and a few ideas on how to improve unstructured

mesh generation

– Write own meshing software …

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 4

Motivation for Open-Source MeshingMotivation for Open-Source Meshing

• Open-source or proprietary software?

• Decision was made rather quickly in favour of OSS

• As a small company it would be extremely difficult to

compete with the commercial codes

• Funding available for an open-source development(funded by the European Space Agency)

• Possibility to generate business with support and

customisation of the software

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 5

open-source „process chain“open-source „process chain“● geometry modelling

● Blender

● Salome

● geometry import and surface meshing

● Gmsh

● NETGEN

● isentropic volume meshing (tetras)

● NETGEN

● Tetgen → ATTENTION: not allowed for commercial applications, NOT OPEN-SOURCE

● an-isotropic boundary layer grids

● … → Engrid

● solver

● OpenFOAM

● Code Saturne

● Elmer

● visualisation

● ParaView

● Open Data Explorer

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 6

Current Status of ENGRIDCurrent Status of ENGRID

• Capable to create unstructured hybrid grids for CFD (prisms & tetras)

• Reliable support for prismatic boundary layers

• Requires a triangulated surface as input

– STL files like for snappyHexMesh

– NETGEN could be used as IGES/STEP → STL converter

• Exports OpenFOAM cases (native format)

• Experimental support for polyhedral grids

– direct export to OpenFOAM

• Basic modification tools (e.g. extrusion, rotation)

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 7

Brief Technical BackgroundBrief Technical Background

• ENGRID uses NETGEN to create tetrahedral grids

from surface triangulations

• Prismatic layers are “seeded” and “grown” into an

existing and healthy grid

• No overlapping in sharp corners

• Polyhedral support keeps the boundary layer as it

is and “dualises” the tetrahedral part of the mesh

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 8

Creating Prismatic LayersCreating Prismatic Layers

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 9

Creating Prismatic LayersCreating Prismatic Layers

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 10

Creating Prismatic LayersCreating Prismatic Layers

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 11

Creating Prismatic LayersCreating Prismatic Layers

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 12

Creating Prismatic LayersCreating Prismatic Layers

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 13

Creating Prismatic LayersCreating Prismatic Layers

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 14

DemonstrationDemonstration

• Engrid is not perfect

– between 1.5 and 2 'man years' development

• We are happy about feedback

• We are happy about suggestions

• We would be even more happy about help ;-)

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 15

DemonstrationDemonstration

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 16

ExamplesExamples

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 17

Vega at Ma=2.7Vega at Ma=2.7

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 18

Vega at Ma=2.7Vega at Ma=2.7

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 19

Vega at Ma=2.7Vega at Ma=2.7

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 20

Vega at Ma=2.7Vega at Ma=2.7

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 21

Vega at Ma=2.7Vega at Ma=2.7

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 22

Vega at Ma=2.7Vega at Ma=2.7

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 23

Vega at Ma=2.7Vega at Ma=2.7

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 24

StageStage-Separation-Separation

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 25

StageStage-Separation-Separation

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 26

9090ºº Bend (Ventilation system Tauerntunnel) Bend (Ventilation system Tauerntunnel)

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 27

9090ºº Bend (Ventilation system Tauerntunnel) Bend (Ventilation system Tauerntunnel)

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 28

9090ºº Bend (Ventilation system Tauerntunnel) Bend (Ventilation system Tauerntunnel)

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 29

9090ºº Bend (Ventilation system Tauerntunnel) Bend (Ventilation system Tauerntunnel)

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 30

9090ºº Bend (Ventilation system Tauerntunnel) Bend (Ventilation system Tauerntunnel)

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 31

Satellite TankSatellite Tank

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 32

Fabric of a FilterFabric of a Filter

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 33

Fabric of a FilterFabric of a Filter

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 34

Fabric of a FilterFabric of a Filter

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 35

Subway StationSubway Station

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 36

Complex Air-DuctComplex Air-Duct

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 37

Planned DevelopmentsPlanned Developments

• Interpolated surfaces

• Anisotropic (prisms) refinement of free shear layers

– feasibility/demonstration for customer

– first step towards adaptive meshing

• Better control of mesh density

– better user interface

– point, line, …, sources

• Interface to more OpenFOAM solvers

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 38

Interpolated SurfacesInterpolated Surfaces

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 39

Interpolated SurfacesInterpolated Surfaces

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 40

Interpolated SurfacesInterpolated Surfaces

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 41

Interpolated SurfacesInterpolated Surfaces

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 42

Interpolated SurfacesInterpolated Surfaces

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 43

Interpolated SurfacesInterpolated Surfaces

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 44

Refinement of Free Shear LayersRefinement of Free Shear Layers

Size in y-direction exaggerated

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 45

Refinement of Free Shear LayersRefinement of Free Shear Layers(supersonic base-flow)(supersonic base-flow)

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 46

Envisaged DevelopmentsEnvisaged Developments

• Adaptive meshing

– y+

– shear layers

– shocks

– ...

• Better support for polyhedral grids

• Hex far fields

– maybe coupled with snappyHexMesh

Oliver Gloth

Engrid: Open-Source Mesh Generation

OpenFOAM “Stammtisch”, 5 Nov. 2009, University of Stuttgart, Campus Vaihingen, Allmandring 30, 70569 Stuttgart page 47

Thank you for your attentionThank you for your attention

engits.com/engrid