Comprehensive Approach to Verification and Validation of CFD Simulations—Part 1: Methodology and Procedures
Tóm tắt
Part 1 of this two-part paper presents a comprehensive approach to verification and validation methodology and procedures for CFD simulations from an already developed CFD code applied without requiring availability of the source code for specified objectives, geometry, conditions, and available benchmark information. Concepts, definitions, and equations derived for simulation errors and uncertainties provide the overall mathematical framework. Verification is defined as a process for assessing simulation numerical uncertainty and, when conditions permit, estimating the sign and magnitude of the numerical error itself and the uncertainty in that error estimate. The approach for estimating errors and uncertainties includes (1) the option of treating the numerical error as deterministic or stochastic, (2) the use of generalized Richardson extrapolation for J input parameters, and (3) the concept of correction factors based on analytical benchmarks, which provides a quantitative metric to determine proximity of the solutions to the asymptotic range, accounts for the effects of higher-order terms, and are used for defining and estimating errors and uncertainties. Validation is defined as a process for assessing simulation modeling uncertainty by using benchmark experimental data and, when conditions permit, estimating the sign and magnitude of the modeling error itself. The approach properly takes into account the uncertainties in both the simulation and experimental data in assessing the level of validation. Interpretation of results of validation efforts both where the numerical error is treated as deterministic and stochastic are discussed. Part 2 provides an example for RANS simulations for a cargo/container ship where issues with regard to practical application of the methodology and procedures and interpretation of verification and validation results are discussed.
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Tài liệu tham khảo
Freitas, C. J. , 1993, “Editorial Policy Statement on the Control of Numerical Accuracy,” ASME J. Fluids Eng., 115, pp. 339–340.
AIAA, 1998, Guide for the Verification and Validation of Computational Fluid Dynamics Simulations, G-077-1998.
Roache, P. J., 1998, Verification and Validation in Computational Science and Engineering, Hermosa Publishers, Albuquerque, New Mexico.
Mehta, U. B. , 1998, “Credible Computational Fluids Dynamics Simulations,” AIAA J., 36, pp. 665–667.
Stern, F., Paterson, E. G., and Tahara, Y., 1996, “CFDSHIP-IOWA: Computational Fluid Dynamics Method for Surface-Ship Boundary Layers and Wakes and Wave Fields,” Iowa Institute of Hydraulic Research, The University of Iowa, IIHR Report No. 381.
Coleman, H. W., and Stern, F., 1997, “Uncertainties in CFD Code Validation,” ASME J. Fluids Eng., 119, pp. 795–803. (Also see “Authors’ Closure,” ASME J. Fluids Eng., Vol. 120, Sept. 1998, pp. 635–636.)
Coleman, H. W., and Steele, W. G., 1999, Experimentation and Uncertainty Analysis for Engineers, 2nd Edition, Wiley, New York, NY.
Rood, E. P., 1996, “Validation Strategy for RANS Computational Ship Hydrodynamics,” 2nd International Conference on Hydrodynamics, Hong Kong.
ITTC, 1996, 21st ITTC Proceedings, “Report of the Resistance Committee,” Bergen/Trondheim, Norway, September.
ITTC, 1999, 22nd ITTC Proceedings, “Report of the Resistance Committee,” Seoul, Korea/Shanghai, China, Sept.
Larsson, L., Stern, F., Bertram, V., 2000, “Gothenburg 2000 A Workshop on Numerical Ship Hydrodynamics,” Chalmers University of Technology, Gothenburg, Sweden, Sept.
Wilson, R. V., Stern, F., Coleman, H., and Paterson, E., 2001, “Comprehensive Approach to Verification and Validation of CFD Simulations—Part 2: Applications for RANS Simulation of A Cargo Container Ship,” ASME J. Fluids Eng., 123, published in the issue, pp. 803–810.
Stern, F., Wilson, R. V., Coleman, H., and Paterson, E., 1999, “Verification and Validation of CFD Simulations,” Iowa Institute of Hydraulic Research, The University of Iowa, IIHR Report No. 407.
Oberkampf, W. L. and Trucano, T. G., 2000, “Validation Methodology in Computational Fluid Dynamics,” AIAA Fluids 2000, Paper No. 2549, Denver, CO.
Coleman, H. W., Stern, F., Mascio, A. Di, and Campana, E., 2001, “The Problem with Oscillatory Behavior in Grid Convergence Studies,” ASME J. Fluids Eng., 123, No. 2, pp. 438–439.
Hoekstra, M., Eca, L., Windt, J., and Raven, H., 2000 “Viscous Flow Calculations for KVLCC2 AND KCS Models Using the PARNASSOS Code,” Proceedings Gothenburg 2000 A Workshop on Numerical Ship Hydrodynamics, Gothenburg, Sweden.
Ferziger, J. H., and Peric, M., 1996, Computational Methods for Fluid Dynamics, Springer-Verlag, New York.
Eca, L., and Hoekstra, M., 2000, “On the Application of Verification Procedures in Computational Fluid Dynamics,” 2nd MARNET Workshop.