Title: Multi-objective optimisation of the model parameters for the realisable k-ε turbulence model

Authors: Luís Medeiros De Souza; Gábor Janiga; Dominique Thévenin

Addresses: Lab. of Fluid Dynamics and Technical Flows, University of Magdeburg, Germany ' Lab. of Fluid Dynamics and Technical Flows, University of Magdeburg, Germany ' Lab. of Fluid Dynamics and Technical Flows, University of Magdeburg, Germany

Abstract: The broad family of k-ε turbulence models is very often used in engineering computational fluid dynamics (CFD). All these models contain semi-empirical parameters that have been determined based on idealised flows. However, it is important to recall that the model parameters are not universal and not even necessarily constant. Consequently, a large span of model parameters can be found in the scientific literature. The objective of the present study is to determine optimised but generally applicable model parameters for the prediction of turbulent quantities for the realisable k-ε model. Four canonic flow configurations are considered simultaneously in the optimisation: channel flow, flow over a backward-facing step, jet flow, and flow over a periodic hill. The optimisation problem thus involves several concurrent objectives that must be fulfilled simultaneously. The obtained optimised model parameters do not differ tremendously from the standard recommended values. Nevertheless, for all the configurations the optimised model delivers better, or at least equally good results compared with experimental measurements. Therefore, employing the model parameter values proposed in this work is recommended, since a slightly improved prediction is obtained at no additional numerical cost.

Keywords: k-epsilon turbulence modelling; multi-objective optimisation; closure constants; RANS modelling; computational fluid dynamics; CFD; model parameters; canonic flow configurations; channel flow; backward-facing step; jet flow; periodic hills.

DOI: 10.1504/PCFD.2017.082523

Progress in Computational Fluid Dynamics, An International Journal, 2017 Vol.17 No.2, pp.90 - 101

Available online: 23 Feb 2017 *

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