A practical guide to CFD simulation
Computational Fluid Dynamics (CFD) helps compare flows, pressures and temperatures. A useful result begins with a clear engineering question and traceable input data.
Define the decision first
Specify what you need to compare: pressure loss, cooling, aerodynamic force or flow distribution. Define operating cases, units and acceptable uncertainty.
Geometry, physics and mesh
The model describes the fluid domain and, for conjugate heat transfer, the relevant solids. Geometry simplifications must preserve the phenomena that matter to the decision.
- Choose steady or transient behaviour, fluid properties and an appropriate turbulence treatment.
- Define inlets, outlets, walls, heat loads and initial conditions with traceable sources.
- Resolve walls, narrow passages and strong gradients, and check sensitivity to mesh refinement.
Convergence is not validation
Monitor residuals, mass and energy balances, and the engineering quantities of interest. A stable solution or a colourful contour plot alone does not demonstrate accuracy. Check sensitivity to mesh, time step and boundary conditions where applicable.
Results that support a decision
Report velocity, pressure and temperature fields, integral quantities and comparisons between variants. Document assumptions, units and limitations. Compare with measurements or suitable reference cases before describing the model as validated.