Investigation of Taylor and Von Karman vortices formed between two concentric rotating cylinders using computational fluid dynamics

In this study, Taylor vortices between two concentric cylinders were analyzed by CFD - Computational Fluid Dynamics analysis of the flow -. STAR-CCM+ software is used for the computations. Analytical results are compared with the results obtained from CFD analysis. Taylor-Couette flow is related to the instability of the flow between two concentric cylinders which rotates at different speeds. Therefore, flow is investigated between two concentric cylinders in case of the outer cylinder is stationary and inner cylinder is rotating. When the rotation speed exceeds a critical Taylor number value, Taylor vortices occur. The critical Taylor number predicted by CFD is compared with the value given in the literature. A two degree sector was used as computational domain assuming the axisymmetry of the flow field. Periodic boundary conditions were used on the left and right sides of the sector. A detailed mesh study was carried out in the present study. Flow computations were performed for different Taylor numbers. Predicted velocity and pressure fields along the radius are compared with the available analytical solutions for the laminar flow. CFD predictions of torque coefficient are compared with the analytical solutions. Additionally, full geometry is used for kinds of different flow regimes found in the literature studies. The results from base and the new geometry were compared. Finally, a heating element that is supposed to represent a simplified heater between the drum and casing for a washing machine is placed as an obstacle inside the flow field. Both three-dimensional and two-dimensional analyses were made and the phenomenon of Von Karman vortex street were investigated. Strouhal number was calculated from the values of frequency and comparisons were made. The flow between two concentric cylinders can be seen as modeling of the flow field between the drum and casing of a washing machine during the spin cycle. Keywords: Taylor Vortices, Computational Fluid Dynamics, Concentric Rotating Cylinders, Von Karman Vortexes, Strouhal number