Introduction to CFD Basics Baidurja Ray Rajesh Bhaskaran Lance R Collins February 7, 2012 This is a quick-and-dirty introduction to the basic concepts underlying CFD. The concepts are illustrated by applying them to simple 1D model problems. We will invoke these concepts while performing ‘case studies’ in FLUENT. Happily for us, these model-problem concepts extend to the more general situations in the case studies in most instances. Since we will keep returning to these concepts while performing the FLUENT case studies, it is worth your time to understand and digest these concepts. We discuss the following topics briefly. These topics are the minimum necessary to perform and validate the FLUENT calculations to come later. 1. Need for CFD 2. Applications of CFD 3. Strategy of CFD 4. Discretization using the finite-difference method 5. Discretization using the finite-volume method 6. Example problem i. Governing equations ii. Discretization using finite-volume method iii. Assembly of discrete system and application of boundary conditions iv. Solution of discrete system v. Grid convergence vi. Discretization error vii. Dealing with nonlinearity viii. Direct and Iterative solvers ix. Iterative convergence x. Numerical stability 7. Explicit and Implicit schemes 8. Turbulence modeling 1