Application of Models for Laminar to Turbulent Transition to Flow Around a Circular Cylinder

Abstract

In many technical fields, for example heat exchangers, circular cylinders are involved in Fluid Structure Interaction (FSI) problems. Therefore correct fluid forces or Strouhal number, drag and fluctuating lift coefficient are needed. On one hand Direct Numerical Simulation (DNS) or Large Eddy Simulation (LES) are too time-expensive, on the other hand great errors can occur, if fluid forces are evaluated with mainstream statistical turbulence models. An incorrect prediction of laminar to turbulent transition and correspondingly a miscalculation of the separation point is the main reason. Several turbulence models and models for laminar to turbulent transition are applied to flow around a circular cylinder in the Reynolds number range from 500 up to 106. Mainly 2D simulations demonstrate the large improvements that are possible with transition models. Additionally calculations are presented to evaluate whether the class of statistical turbulence and transition models is influenced by three dimensional modeling. Results will be presented for the Shear Stress Transport (SST) and the Wilcox98 k-ω turbulence model. While the latter can be modified according to a proposal of Wilcox (1998) to take transition into account, the commercial code we use at our institute provides several extensions for transition modeling together with the SST model.