On the Calculation of the Flow Around 2-D Square Cylinder with Rounded Corners

This paper presents the calculation of the flow around a square cylinder with rounded-corners assuming two-dimensional and incompressible flow. The selected mathematical model is the Reynolds-Averaged (ensemble averaged) Navier-Stokes equations supplemented by the two-equation k − ω SST eddy-viscosity turbulence model. The goal of the study is to investigate the influence of the choice of the problem settings on the prediction of several meaningful flow quantities for practical applications.
Two main choices are addressed in this work: the size of the computational domain and the specification of the pressure and turbulence quantities boundary conditions. The selected Reynolds number is typical of offshore applications (1.74×10⁵) and grid/time refinement studies are performed for all conditions to enable the estimation of the numerical uncertainty. All calculations are performed with the (U)RANS solver ReFRESCO.
The results show that the level of grid/time refinement required to obtain negligible numerical uncertainties is more demanding than the typical values found in the open literature. Nonetheless, the data also show that the size of the domain and the specification of pressure and turbulence quantities (inlet) boundary conditions have a significant influence on the predicted flow quantities. Therefore, any simulation for a proper Validation procedure must follow the correct domain size and boundary conditions. Unfortunately, all this information is seldom available and so this hampers the possibility to evaluate correctly the modelling error.