Engineering disclaimer: These calculators provide preliminary estimates using simplified analytical equations and empirical correlations. Results depend on geometry, reference conditions, flow regime, fluid properties, numerical method, wall treatment and modelling assumptions. They do not replace mesh- and time-step-sensitivity studies, solver-specific guidance, validation data, applicable standards, or professional engineering assessment. These tools are freely offered by 42 CFD Lab. Please use them only as reference material. By using them, you acknowledge that 42 CFD Lab is not responsible or liable for any decision, loss, damage, design outcome, or other consequence arising from their use.