# BlockMesh by Divyesh Variya (DD Fluids)

Go back to Meshing by Divyesh Variya.

Go back to Day 6 of 3-week series.

# blockMesh

The blockMesh is a very simple and powerful tool or utility of OpenFOAM to create simple 1D/2D/3D geometries and mesh it. In this tutorial series, a detailed overview is given using a lid-driven cavity case.

All major sections of blockMeshDict are discussed with different hands-on modifications. In addition, an explanation of the sub-section edges & mergePatchPair of blockMeshDict is explained in these tutorials. How one can create an arc and polyline using edges section and merge two blocks using mergePatchPair section is discussed with hands-on modifications. Additionally, this tutorial describes how one can create finer mesh near a particular face in blockMeshDict, simple grading is used.

## blockMeshDict [vertices|blocks|boundary]

Description: A detailed overview explained in this tutorial using a lid-driven cavity case. The three major sections of blockMeshDict are discussed with different hands-on modifications.

Points covered:

• How to define vertices
• How to define block
• How to discretize a domain
• How to define physical boundaries
• How to scale geometry

## blockMeshDict [edges]

Description: An explanation of sub-section edges of blockMeshDict is explained in this tutorial. How one can create an arc and polyline using the edges section is discussed with hands-on modifications.

Points covered:

• How to create a curved face
• How to create 3 point arc
• How to create a polyline
• How to create finer and smoother face
• How to add points from excel to blockMeshDict

Description: To create finer mesh near a particular face in blockMeshDict, simple grading is used. In this tutorial, few options of simpleGrading are explained for example, how to create a finer grid near a single face and two faces.

Points covered:

• How to create a finer grid near a face
• How to distribute geometry and no. of cells
• How expansion ratio work in blockMeshDict

## blockMeshDict [Multiple blocks]

Description: This video tutorial covers how to define multiple blocks for slightly complex geometries in blockMeshDict. For demonstration, T-shape geometry is created and four blocks have been added. For better understanding try to add one more block below and make a "plus" shape geometry by yourself.

Points covered:

• How to add vertices for extra blocks
• How to add multiple blocks
• Tip-1: Always sketch your geometry first
• Challenge: Add one more block and create "plus" shape geometry