Analysis of Detached-Eddy Simulation for the Flow Around a Circular Cylinder with Reference to PIV Data

A detailed validation study is presented for the detached-eddy simulation (DES) of the flow around a circular cylinder at a high sub-critical Reynolds number. Good comparability with unsteady experimental field data is facilitated by the confined and clearly-defined geometry, although some uncertainty remains regarding the free stream turbulence intensity. The combination of DES with an appropriate low-dissipative hybrid numerical convection scheme and high temporal resolution delivers excellent agreement with the experiment for the time and phase-averaged fields as well as the spectral content. A strong sensitivity of the solution to the numerical time step size has been identified, which is attributed to time-filtering effects damping the development of resolved turbulence in the early shear layer. Recommendations are made concerning a CFL-type criterion for the temporal resolution of DES and future studies involving a still finer time step are outlined.