Mesh Generation with SimScale
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The document discusses a webinar on mesh generation using SimScale, a cloud-based engineering simulation platform founded in 2012. It covers the importance of meshing in engineering simulations, what constitutes a good quality mesh, and various practices and techniques for generating meshes effectively. It also highlights advanced mesh settings, including considerations for mesh refinements and quality factors that enhance simulation accuracy.
Mesh Generation with SimScale
- 1. By Arnaud Girin CFD, FEA, and thermo webinar Mesh Generation with SimScale
- 2. About SimScale Who we are ● Founded in 2012 ● Offices in Munich, Boston, and New York ● 80+ employees across 6+ time zones ● 150,000 users worldwide ● More than 300k simulation projects
- 3. We created the world’s first cloud-based engineering simulation platform. ● Fluid dynamics (CFD) ● Solid mechanics (FEA) ● Thermodynamics All accessible via a web browser. About SimScale What we do
- 4. ● What is meshing? ● Why is meshing important? ● What is a good quality mesh? ● SimScale new mesher ● Best practices and what to avoid Today’s topic Mesh generation
- 5. Mesh setup Mesh generation with SimScale How meshing will help your simulation
- 6. A mesh is a division of a large volume into smaller, simple volumes called elements. What is a mesh in engineering simulation? ORIGINAL CAD MODEL MESHED MODEL
- 7. ● We cannot simply use an equation such as: f (inlet flow rate, outlet location ) = outlet flow rate Why do we need a mesh? Flow through a pipe 1 l/s of water What is the flow rate coming out of this pipe? What is the flow rate coming out of this pipe?
- 8. Flow through a pipe Why do we need a mesh? ● We can however: ○ subdivide the volume of water inside the pipe ○ solve the flow equations (for velocity, pressure, etc.) in primitive volumes We first solve the flow in this volume Then we solve it in this other volume ...and to the next one
- 9. A mesher is an algorithm that will break down the 3D modeled volumes into small primitive volumes called elements. How is the mesh generated? Hex Tet PyramidPrism
- 10. Mesh quality Let’s talk about quality Element proportion How close is each element proportion to an ideal element? Relative smoothness between elements Is the transition between elements geometrically smooth? In both cases: the solver will run faster and with more stability if these two are properly maintained.
- 11. Let’s talk about quality Aspect ratio Low aspect ratio : 1 ideal Shortest edge Longest edge Shortest edge Longest edge Aspect ratio = High/poor aspect ratio
- 12. We want to keep these two close to: 60° for tri and tet elements 90° for quad and hex elements Let’s talk about quality Min/max angle Max angle Min angle
- 13. Let’s talk about quality Volume ratio Larger volume Smaller volume Volume ratio =
- 14. How to check the quality of your mesh in SimScale? Mesh generation Check the max values!
- 15. The mesher Mesh generation Standard Hex-dominant Our new standard: Let’s focus on this one. Still great and useful in some cases!
- 16. The standard mesher Mesh generation Hex elements in the core Triangle elements on the surfaces (faces of prism/tet elements ) Pyramid/Tet elements between core and surfaces Inflate boundary layer refinement Small details captured
- 17. The standard mesher options Mesh generation CFD FEA New feature!
- 18. Advanced settings ● Narrow gap (0.1mm) fully captured ● Very poor aspect ratio: 13919 ○ Should always stay within the 100s Small feature suppression OFF
- 19. Advanced settings ● Narrow gap (0.1mm) NOT captured ● Very good aspect ratio: 2.4! Small feature suppression ON
- 20. Advanced settings ● Ratio of the gap length over the element edge length ○ If the number of gap element is 2, there will be 2 elements across the gap Number of gap elements 210 Gap length Element edge length Gap element = 0.33
- 21. Mesh refinements: Why are they needed? Mesh Generation with SimScale Fine: the elements are not/less visible Coarse: you can guess the elements
- 22. Surface Mesh refinements ● Pick a face ● Assign it a maximum edge length
- 23. ● Define a region in the form of a geometry primitive ● Assign it a maximum edge length Region Mesh refinements
- 24. Mesh refinements ● To closely capture flow velocity at the wall ● Important for an accurate solution including: ○ reaction forces ○ heat exchange ○ pressure drop and friction ● The correct height of the layers is defined by many factors: ○ velocity ○ viscosity ○ turbulence intensity Inflate boundary layer Wall Velocity of the fluid Velocity goes down to zero at the wall
- 25. Inflate boundary layer 1 Mesh refinements 1.5 growth 1.5 growth 0.4 1
- 26. Inflate boundary layer 2 Mesh refinements
- 27. Mesh Generation with SimScale Thank you! CFD, FEA, and thermo webinar