How can you simulate airflow around a vehicle using CFD?

1 Choose a CFD software

The first step is to choose a CFD software that suits your needs and budget. There are many CFD software available, ranging from open-source to commercial, from general-purpose to specialized, from user-friendly to complex. Some examples are OpenFOAM, ANSYS Fluent, Star-CCM+, and SimScale. You should compare the features, capabilities, support, and cost of different CFD software and select the one that meets your requirements and expectations.

2 Prepare the geometry and mesh

The next step is to prepare the geometry and mesh of your vehicle and the surrounding fluid domain. The geometry is the 3D model of your vehicle, which can be imported from a CAD software or created within the CFD software. The mesh is the discretization of the geometry and the fluid domain into small cells or elements, which are used to solve the governing equations of fluid flow. The quality and resolution of the mesh affect the accuracy and efficiency of the CFD simulation. You should use appropriate meshing tools and techniques to generate a suitable mesh for your vehicle and the airflow.

3 Set up the boundary conditions and parameters

The third step is to set up the boundary conditions and parameters for your CFD simulation. The boundary conditions define the behavior of the fluid at the boundaries of the domain, such as the inlet, outlet, walls, and symmetry planes. The parameters include the fluid properties, such as density and viscosity, the flow regime, such as laminar or turbulent, and the turbulence model, such as k-epsilon or k-omega. You should choose the boundary conditions and parameters that match the physical conditions of the airflow around your vehicle.

4 Run the simulation and monitor the convergence

The fourth step is to run the simulation and monitor the convergence. The simulation is the process of solving the fluid flow equations on the mesh using numerical methods and algorithms. The convergence is the measure of how close the solution is to the true solution. You should run the simulation until the convergence criteria are met, which means that the solution is stable and accurate. You should also check the residuals, which are the errors in the solution, and the mass and momentum conservation, which are the balances of mass and momentum in the domain.

5 Analyze the results and visualize the airflow

The final step is to analyze the results and visualize the airflow. The results are the output of the simulation, such as the pressure, velocity, temperature, drag, lift, and coefficients of your vehicle and the airflow. You should use post-processing tools and techniques to extract, process, and interpret the results and compare them with your objectives and expectations. You should also use visualization tools and techniques to display the results graphically, such as contours, vectors, streamlines, and iso-surfaces. Visualization can help you understand the flow patterns, features, and phenomena around your vehicle.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?