Numerical investigation of turbulent flow and mixed convection around a wavy cylinder

Abstract

The performance of different scale-resolving simulation (SRS) models in resolving the turbulent flow structures and forced convection around a wavy cylinder (TFWC) at subcritical Re = 3000 is compared firstly. The SRS models include the SST scale adaptive simulation (SAS), the SST delayed detached-eddy simulation (DDES), and the production-limited DDES (PL-DDES) models. The simulation results on a coarse grid resolution testify that the PL-DDES model is superior to the SAS and DDES models. Another primary purpose is exploring the turbulent flow and mixed convection around a wavy cylinder using the PL-DDES model. For the contra flow (Richardson number = −0.3), the Strouhal number, the drag coefficient, and the Root-Mean-Square (RMS) lift coefficient decrease, but the length of the recirculation zone increases. In contrast, it is inverse results in the parallel flow (Richardson number = 0.3). Due to the buoyancy effect, the region of the 3 d flow structures in the contra flow and the parallel flow are respectively larger and smaller than those in the non-buoyancy flow. The laminar mixed convection is dominant around the cylinder in the contra flow. The turbulent mixed convection plays an essential role in the wake region for the parallel flow. In the windward region, the laminar mixed convection is dominant for both flows. The Nusselt number decreases and increases in the contra flow and the parallel flow, respectively.