OpenFOAM Tutorial (Chpt 2 — Section 2): Create Your First Mesh blockMesh (blockMeshDict Explained)

The full tutorials with supporting Sim files, geometries, documents, and teacher support are placed at Udemy. Please refer there. The courses are really cheap compared to the efforts it took to create them, but if anyone needs to have it free, contact me and I will find a way. StarCCM Courses: https://www.udemy.com/course/star-ccm-expert-applications-vol-1-real-engineering/?referralCode=536C577A98868E316EC9 https://www.udemy.com/course/complete-cfd-simulation-in-starccm-advanced/?referralCode=C05897D188FB69CC8296 https://www.udemy.com/course/star-ccm-for-beginners-from-zero-to-your-first-simulation/?referralCode=EFAD8399E5FE89354471 Other courses we have: https://www.udemy.com/course/openfoam-for-beginners-from-installation-to-real-simulation/?referralCode=C9B5C2ACEDD226EAD49F https://www.udemy.com/course/solidworks-without-the-confusion-a-clear-beginner-course/?referralCode=04CC037F67BFD995F1EA https://www.udemy.com/user/sahar-rouzbahani-2/ ## Title options (Chapter 2 — Section 2) In this section of **Chapter 2**, we generate the **first mesh** for our **lid-driven cavity** case using **blockMesh**—the classic structured mesher in OpenFOAM. We start by confirming something important: at this stage the case has **no mesh yet**, so we must create computational cells before any solver can run. Then we open: ✅ `system/blockMeshDict` and learn how OpenFOAM mesh dictionaries are structured, including the header and the **FoamFile** section (which we typically don’t change). Step-by-step, we build the mesh definition: * define the **vertices** (points) * define a single **hex block** using vertex indices * set the cell count: **20 × 20 × 1** (OpenFOAM expects 3D meshes—2D is done using **1 cell in the z-direction** + **empty** patches) * set **grading** to uniform: `(1 1 1)` * define boundary patches: **movingWall (lid)**, **fixedWalls**, and **frontAndBack (empty)** * understand the **scale** option and what it does Then we run the mesher correctly from the **case root directory**: ✅ `blockMesh` and verify the output (points, faces, patches, total cells). Finally, we visualize the mesh using: ✅ `paraFoam` and confirm the grid is correct in ParaView (“**Surface With Edges**”), including the key 2D indicator: **only 1 cell in Z**. Next, we move to the **boundary conditions** and start setting up the physics of the cavity case. --- ## Keywords (copy/paste) OpenFOAM blockMesh, blockMeshDict explained, OpenFOAM mesh generation, structured mesh OpenFOAM, hexahedral mesh OpenFOAM, lid-driven cavity mesh, cavity case OpenFOAM, 20x20 mesh OpenFOAM, 2D OpenFOAM empty boundary, frontAndBack empty patch, system/blockMeshDict, vertices blocks grading, hex block OpenFOAM, scale in blockMeshDict, constant/polyMesh, points faces owner neighbour boundary, run blockMesh from case directory, paraFoam mesh view, ParaView Surface With Edges, OpenFOAM tutorial chapter 2 --- ## Hashtags #OpenFOAM #CFD #blockMesh #blockMeshDict #MeshGeneration #HexMesh #ParaView #paraFoam #FluidDynamics #ComputationalFluidDynamics #OpenSourceCFD #Engineering #LidDrivenCavity #OpenFOAMTutorial --- If you want, I can also **generate the white-background thumbnail** for this section in the same visual style as your other thumbnails—just say: **“create thumbnail for section 2 (white background)”**.