Our group takes a holistic view of uncertainty in CFD (and in scientific computing in general). The three sources contributing to the uncertainty in a CFD simulation prediction are:

  • Uncertainty due to the model inputs - addressed through uncertainty propagation
  • Uncertainty due to numerical approximations - addressed through verification techniques
  • Uncertainty due to the form of the model - addressed through validation techniques

These three sources of uncertainty are shown graphically below (reproduced from Roy and Balch, 2012).


  • W. L. Oberkampf and C. J. Roy, Verification and Validation in Scientific Computing, Cambridge University Press, Cambridge, 2010.
  • C. J. Roy and W. L. Oberkampf, “A Comprehensive Framework for Verification, Validation, and Uncertainty Quantification in Scientific Computing,” Computer Methods in Applied Mechanics and Engineering, Vol. 200, 2011, pp. 2131-2144 (DOI: 10.1016/j.cma.2011.03.016).
  • C. J. Roy and M. S. Balch, “A Holistic Approach to Uncertainty Quantification with Application to Supersonic Nozzle Thrust,” International Journal for Uncertainty Quantification, Vol. 2, No. 4, 2012, pp. 363-381 (DOI: 10.1615/Int.J.UncertaintyQuantification.2012003562).