A study of solving Navier-Stokes equations with a finite volume method based on polygonal unstructured grids and the computational analysis of ground vehicle aerodynamics
MetadataShow full item record
Navier-Stokes (N-S) equations describe the motion of fluid flow in the nature and they are called the governing equations of fluid flows. Solving Navier-Stokes equations is of great interest to the scientists and researchers. Due to the high nonlinearity, achieving the analytical solutions for the N-S equations is extremely difficult, if not impossible. Thus, people have to switch to numerical solutions with putting on certain restrictions on the N-S equations. This leads to the development of Computational Fluid Dynamics (CFD). This dissertation contains two major sections. The first section is about theoretical study of CFD. We go through the whole process that a CFD analysis normally requires: generating mesh, setting boundary conditions and achieving numerical solutions of N-S equations, and post-processing to achieve flow field plots. An in-house 2- D CFD code based on unstructured polygonal mesh is presented, in which a new momentum interpolation method is developed and implemented to calculate the flow flux on the cell faces. The 2-D code is also validated by comparing the numerical results with widely-known analytical results, if available, or by benchmarking with the results produced by commercial CFD software packages. The second section of this dissertation is about one of the applications of CFD in modern auto industry – ground vehicle aerodynamics. The cross wind effect on a sport utility vehicle (SUV) is studied and analyzed using CFD methods and compared with available wind tunnel experimental results. The first section contributes to the philosophy of mechanical physics and the second section aims to fulfill the purpose of engineering.