Taylor-Couette Flow with an Axial Flow

초록

In this study, numerical simulations of Taylor-Couette flow with an imposed axial flow were carried out, and compared with the recent PIV measurements of Wereley and Lueptow [Phys. Fluids, Vol. 11, No. 12 (1999)]. It is revealed that an axial flow stabilizes the flow field as expected and the numerical results obtained are in excellent agreement with those of Wereley and Lueptow's experiments. It is confirmed that the `shift-and-reflect' symmetry is valid not only for Taylor-Couette flows without an imposed axial flow but also for the flows with an imposed axial flow, if the exact steady axial velocity profile is subtracted from the computed flow field. A traveling wave along azimuthal direction can be detected from instantaneous velocity vector fields, and it is verified that the temporal measurements of Wereley and Lueptow on a given meridional section are valid. In various cases of Taylor and Reynolds numbers, detailed flow information is obtained and the type of Taylor vortices is identified. Growth rate of the flow instability is defined and used in predicting the type of the vortices without ``full" simulation. It is also shown that the torque coefficient on the inner cylinder surface is significantly reduced by the axial flow. The results obtained in this study also demonstrate that the numerical analysis employed for the current investigation is suitable and economical.