Verification of commercial CFD codes using hydrodynamic instability

Verification of commercial CFD codes using hydrodynamic instability

Reis, D. C.; Gennaro, E. M.; Simões, L. G. C.; Medeiros, M. A. F.

Full Article:

Code verification is an essential process in computational analysis. The lack of access to the source code in commercial softwares often makes this process very difficult to be performed. Usually, the use of manufactured solutions is not feasible and analytical solutions of the Navier Stokes Equations are not sufficient because normally many terms of the equations are null. The situation is more troublesome for unsteady flows since it is more difficult to find analytical solutions and errors can accumulate in time. Simulations focused on turbulent fluctuations or sound wave generation associated with aeroacoustics applications are even more important and difficult to perform, because even minute errors can have a large impact on the flow. Here it is proposed a code verification method based on the simulation of a mixing layer, a canonical flow that transitions to turbulence. This flow is linearly unstable and the stability calculation affords a semi analytical solution. The paper shows how this solution can be used for classification of code performance. In the study, several commercial codes have been tested and very different code performances were obtained, both in terms of accuracy and grid requirements.

Code verification is an essential process in computational analysis. The lack of access to the source code in commercial softwares often makes this process very difficult to be performed. Usually, the use of manufactured solutions is not feasible and analytical solutions of the Navier Stokes Equations are not sufficient because normally many terms of the equations are null. The situation is more troublesome for unsteady flows since it is more difficult to find analytical solutions and errors can accumulate in time. Simulations focused on turbulent fluctuations or sound wave generation associated with aeroacoustics applications are even more important and difficult to perform, because even minute errors can have a large impact on the flow. Here it is proposed a code verification method based on the simulation of a mixing layer, a canonical flow that transitions to turbulence. This flow is linearly unstable and the stability calculation affords a semi analytical solution. The paper shows how this solution can be used for classification of code performance. In the study, several commercial codes have been tested and very different code performances were obtained, both in terms of accuracy and grid requirements.

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DOI: 10.5151/meceng-wccm2012-18114

Referências bibliográficas

• [1] Roache, P. J., “Quatification of uncertainty in computational fluid dynamics”. Ann. Rev. Fluid Mech. 29, 123-160, 1997.
• [2] Obertkampf, W. L.; Trucano, T. G.; Hirsch, “Verification, validation and predictive capability in computational engineering and physics”. Appl. Mech. Rev. 57(5), 345-384, 2004.
• [3] Roy, C. J., “Review of code and solution verification procedures for computational simulation”. J. Comp. Phys. 205, 131-156, 2005.
• [4] Kim, J. and Moin, P., “Application of a fractional-step method to incompressible Navier- Stokes equations”. J. Comp. Phys. 59, 308-323, 1985.
• [5] Lin,C.C., “The theory of Hydrodynamic Stability”. CUP, 1955.
• [6] Criminale, W. O., Jackson, L. T. and Joslin, R. D., “Theory and Computation in hydrodynamic stability”. Cambridge University Press, 2003.
• [7] Germanos, R. A. C., Souza, L. F and Medeiros, M. A. F. “Numerical investigation of the three-dimensional secondary instabilities in the time-developing compressible mixing layer”. J. Braz. Soc. Mech. Sci. Andamp; Eng 31(2), 125-136, 2009.
• [8] Gennaro, E. M., Colaciti, A. K. and Medeiros, M. A. F. “On the controversy regarding the effect of flow shear on the Strouhal number of cylinder vortex shedding”. Ocean Engineering, 2012 (submitted).
• [9] Sandham, N. D. and Reynolds, W. C. “Three-dimensional simulations of large eddies in the compressible mixing layer”. J. Fluid Mech. 224, 133-158, 1991.

Como citar:

Reis, D. C.; Gennaro, E. M.; Simões, L. G. C.; Medeiros, M. A. F.; "Verification of commercial CFD codes using hydrodynamic instability", p-780-794. In: In Proceedings of the 10th World Congress on Computational Mechanics [= Blucher Mechanical Engineering Proceedings, v. 1, n. 1]. São Paulo: Blucher, 2014.
ISSN 23580828, DOI 10.5151/meceng-wccm2012-18114