How can you optimize meshing and boundary conditions for ANSYS Fluent CFD simulations of aerodynamics?

1 Meshing basics

Meshing is the process of dividing your CAD model into smaller elements or cells that represent the fluid domain. The quality and size of your mesh affect the accuracy and speed of your simulation. A finer mesh can capture more details and resolve complex flow features, but it also increases the computational cost and time. A coarser mesh can save resources, but it may miss some important effects and introduce errors. Therefore, you need to balance the trade-off between mesh resolution and performance.

2 Meshing strategies

There are different types of meshing strategies that you can use in Fluent, such as structured, unstructured, hybrid, and adaptive. Each one has its advantages and disadvantages depending on the geometry and flow physics of your problem. For example, structured meshes are more efficient and suitable for simple shapes and laminar flows, but they are difficult to generate for complex geometries and curved surfaces. Unstructured meshes are more flexible and can handle any shape and turbulent flow, but they are less efficient and require more memory. Hybrid meshes combine both types and can offer a good compromise. Adaptive meshes can adjust the mesh size during the simulation based on the flow solution, but they are more complex and require more iterations.

3 Meshing tips

Optimizing your meshing requires following some general guidelines and best practices. For example, you should use the appropriate meshing strategy for your problem and geometry, such as Fluent Meshing Mode or Workbench Meshing component. Additionally, you should use mesh quality check tools like Fluent Mesh Checker or Mesh Metrics to identify any issues or defects. Furthermore, mesh refinement and coarsening tools like Fluent Mesh Adaptation or Mesh Controls can be used to adjust the mesh size locally or globally. Lastly, mesh smoothing and optimization tools like Fluent Mesh Morphing or Mesh Optimization can be used to improve the mesh quality and reduce errors and numerical diffusion.

4 Boundary conditions basics

Boundary conditions are the inputs that you specify at the boundaries of your fluid domain to define the flow properties and behavior. They are essential for solving the governing equations and obtaining a realistic and meaningful solution. The choice and setting of your boundary conditions depend on the nature and objectives of your simulation.

5 Boundary conditions types

There are different types of boundary conditions that you can use in Fluent, such as velocity inlet, pressure outlet, wall, symmetry, periodic, mass flow inlet, and pressure far-field. Each one has its own parameters and options that you can adjust to match your problem and scenario. For example, velocity inlet lets you specify the flow velocity and direction at the inlet, pressure outlet lets you specify the static or total pressure at the outlet, wall lets you specify the wall temperature and roughness, symmetry lets you model a symmetric or mirror plane, periodic lets you model a repeating or cyclic pattern, mass flow inlet lets you specify the mass flow rate at the inlet, and pressure far-field lets you model an inviscid flow at infinity.