ENME413
Applied Computational Fluid Dynamics
Syllabus
- Introduction to CFD and Fluid Mechanics Review (6 hours)
- History and role of CFD in modern mechanical engineering design
- Review of fluid kinematics: velocity field, streamlines, pathlines and flow classification
- Laminar versus turbulent flow, Reynolds number and its engineering significance
- CFD workflow: geometry, meshing, boundary conditions, solver and post-processing
- Advantages, limitations and validation of CFD against experiments and analytical solutions
- Interface layout, file structure and basic navigation of CFD software interface
- Governing Equations and Numerical Foundations (9 hours)
- Continuity equation in differential and integral forms
- Navier-Stokes equations and physical meaning of each term
- Enthalpy formulation and simplified heat transfer equation
- Application of Euler equations and Stokes flow
- Boundary conditions: inlet, outlet, wall (no-slip), symmetry and periodic
- Matrix systems, direct and iterative solution methods
- Numerical errors: truncation error, round-off error, consistency and stability
- Convergence concepts: residuals, iteration and physical convergence indicators
- Discretization Methods (12 hours)
- Finite difference method (FDM): Taylor series expansion, forward, backward and central differences
- Accuracy and order of approximation: first-order and second-order schemes
- Finite volume method (FVM): control volume formulation, flux balance, cell-centered approach
- Discretization of the diffusion term and convection term
- Upwind, central differencing and hybrid schemes: numerical diffusion and stability
- Time discretization: explicit and implicit schemes and CFL stability condition
- Pressure-velocity coupling: physical motivation and SIMPLE algorithm
- Iterative linear solvers used in CFD: Gauss-Seidel, conjugate gradient and algebraic multigrid
- Practical application of FVM
- Mesh Generation and Solver Setup (9 hours)
- Types of meshes: structured, unstructured and hybrid
- 2D and 3D mesh elements: triangles, quads, tetrahedra, hexahedra and prism layers
- Mesh quality metrics: skewness, aspect ratio and orthogonality
- Near-wall mesh requirements: boundary layer resolution and the y+ parameter
- Geometry preparation and meshing workflow
- Mesh independence study: systematic refinement and solution sensitivity analysis
- Defining boundary conditions: velocity inlet, pressure outlet, wall and symmetry
- Solver configuration: steady-state vs. transient, under-relaxation factors and convergence monitoring
- Post-processing: contour plots, vector fields, streamlines and surface integrals
- Turbulence Modeling (3 hours)
- Physical nature of turbulence: chaotic fluctuations, energy cascade and engineering implications
- Reynolds-Averaged Navier-Stokes (RANS) approach: time-averaging and the closure problem
- Common turbulence models: k-epsilon and k-omega SST
- Selection criteria of a turbulence model
- Wall functions: role in near-wall treatment and relationship to mesh y+ requirements
- CFD Applications (6 hours)
- Internal flow: pipe flow, duct flow and pressure drop prediction in pipe networks
- External aerodynamics: flow over bluff bodies and streamlined profiles with lift and drag evaluation
- Heat transfer applications: forced convection in channels, cooling fins and heat exchangers
- HVAC and ventilation: airflow distribution, thermal comfort and indoor environment simulation
- Fluid machinery: flow through pump impellers and turbine passages using rotating reference frames
- Case studies and result interpretation: identifying flow features, validating against benchmarks
Practicals
- Orientation session: ANSYS Workbench interface, units and file management
- Laminar pipe flow simulation: velocity profile and comparison with the Hagen-Poiseuille solution
- 2D lid-driven cavity: mesh convergence study and visualization of recirculation zones
- Flow over a flat plate: boundary layer growth, skin friction and comparison with Blasius theory
- External flow over a circular cylinder: pressure distribution and drag coefficient measurement
- 2D airfoil simulation (NACA 0012): lift and drag at varying angles of attack
- Forced convection in a channel with heated walls: temperature contours and Nusselt number estimation
- Heat exchanger geometry: inlet/outlet temperature difference and pressure drop analysis
- Centrifugal pump impeller flow: rotating reference frame setup, pressure rise and velocity vectors
- Mini-project: student-chosen mechanical engineering flow problem, report covering geometry, mesh, results and validation
Evaluation
Final exam questions cover all chapters. Approximate marks distribution (total 60 marks over 45 hours):
- Introduction to CFD and Fluid Mechanics Review, Governing Equations and Numerical Foundations: 20 marks
- Discretization Methods: 20 marks
- Mesh Generation and Solver Setup, Turbulence Modeling: 15 marks
- CFD Applications: 5 marks