Verification and validation
The two words mean different things. Verification checks that a model solves its equations correctly, for example by reproducing known solutions. Validation checks that the equations describe the real engine, which ultimately needs measurements.
A test ladder
- Physics sanity: conservation laws and limits checked on every prediction.
- Known answers: textbook cases and reference codes such as NASA CEA.
- Blind test: designs the AI has not seen, compared with full CFD.
- Beat the baseline: better than a classical design under the same limits, or say so.
- Printed part: CT scan of the channels, cold-flow test of the pressure loss.
- Hot-fire: thrust, chamber pressure and wall temperature compared with the prediction.
Each step costs more than the one before, so cheap tests filter designs early.