Quiz 3

Question 1

What is verification? Give a short description.

Answer 1

Verification assessment determines if the programming and computational implementation of the conceptual model is correct. It examines the mathematics in the models through comparison to exact analytical results. Verification assessment examines for computer programming errors.
-Solving the equations right

Question 2

What is validation? Give a short description.

Answer 2

Validation assessment determines if the computational simulation agrees with physical reality. It examines the science in the models through comparison to experimental results.
- Solving the right equations

Question 3

What sources of uncertainty exist in CFD?

Answer 3

Modelling errors:
▪ Physics not understood
▪ Empirical coefficients employed in the model
▪ Physical model simplified

Question 4

What sources of acknowledged errors exist in CFD?

Answer 4

Modelling errors
▪ Round-off error
▪ Truncation error
Convergence error

Question 5

What sources of unacknowledged errors exist in CFD?

Answer 5

Programming error

User error

Question 6

Looking in the FDS verification manual (16.1), what is the typical bias when predicting the hot gas layer temperature?

Answer 6

1.03 (overprediction)