How to increase quality of Poor orthogonal quality around edges of propeller blades in Ansys Fluent

 Here are some steps you can take to improve the poor orthogonal quality around the edges of propeller blades in Ansys Fluent:

**Meshing Strategies:**

1. **Refine Mesh:** The most common solution is to refine the mesh around the propeller blades. This creates smaller, better-shaped cells that can more accurately capture the flow behavior. You can refine the mesh globally or focus on specific regions around the blade edges where the quality is poor.

2. **Local Sizing:** Utilize local sizing to define a specific target mesh size for the blade edges. This ensures a finer mesh is generated in those critical areas while maintaining a coarser mesh elsewhere for efficiency.

3. **Structured Meshing:** Consider using a structured meshing approach, particularly near the blade edges. Structured meshes offer better control over cell shapes and can lead to improved orthogonal quality compared to unstructured meshes.

4. **Curvature-Based Meshing:** Implement curvature-based meshing techniques that adapt the mesh to the curvature of the blade edges. This ensures the cells conform better to the geometry and avoids skewness.

**Mesh Controls:**

1. **Minimum Cell Quality:** Adjust the minimum orthogonal quality setting in your meshing controls. This sets a threshold for acceptable cell quality. However, be mindful not to set it too high, as it might lead to excessive mesh refinement and longer simulation times.

2. **Avoid Automatic Smoothing:** Automatic smoothing can sometimes worsen orthogonal quality near edges. Consider disabling it for the propeller blade regions and see if it improves the results.

**Alternative Meshing Techniques:**

* **Spreading Function:** If the blade geometry is complex, explore using a spreading function to control mesh growth away from the blade surface. This can help maintain good cell shapes near the edges.

* **overset Meshing:** For complex geometries like rotating blades, overset meshing can be a good option. It allows for independent meshing of the blades and the surrounding fluid, potentially improving mesh quality around the edges.

**Additional Tips:**

* **Preview Mesh:** Utilize the mesh preview option to visualize the cell quality before running the simulation. This allows you to identify areas that need further refinement.

* **Mesh Sensitivity Study:** Once you've improved the mesh quality, perform a mesh sensitivity study to ensure the results are no longer overly dependent on the mesh size.

* **Consult Documentation:** Refer to the Ansys Fluent documentation for detailed information on meshing techniques and quality controls: [https://www.afs.enea.it/project/neptunius/docs/fluent/html/ug/node140.htm](https://www.afs.enea.it/project/neptunius/docs/fluent/html/ug/node140.htm)

By applying these strategies and carefully considering the meshing techniques for your propeller blade geometry, you can significantly improve the orthogonal quality near the edges and obtain more accurate results in your Ansys Fluent simulations.