Exercise

Introduction

The geometry of a catalytic converter is given (see Figure below). For the simulation of the interior flow a unstructured, hexahedral-dominant mesh should be created.

Navigate with your terminal to the extracted sub-directory 3_catalytic_converter within the 2_mesh_generation directory. This folder only contains the geometry file geometry.obj.

Tasks

1. Copy the system directory from the buildings case to 3_catalytic_converter.
2. Adjust the meshDict to create an unstructured, hexahedral-dominant mesh meeting the following requirements:
   • Maximum cell size of 8 mm
   • Surface-based refinement at patch2 with a cell size of 2 mm and a refinement thickness of 4 mm
   • Region-based refinement at the center of the catalytic converter between \(-100 \leq x \leq 100\) with a cell size of 4 mm
   • Inflation layers at patch2 with 5 layers and a growth ratio of 1.2
   • Rename the patches to inlet, outlet and walls and set their corresponding types correctly
   • The total cell count should be around 180,000 - 220,000 cells, which should be varified using checkMesh.
3. Make sure the scaling of the mesh is correct.
4. Check the mesh quality and identify regions with elevated non-orthogonality.
5. Create two copies the 3_catalytic_converter directory named 3_catalytic_converter_medium and 3_catalytic_converter_fine. Repeat the mesh generation in these new directories and create a refined medium and fine mesh suitable for a mesh independency study.