Effects of Reynolds number on dean vortices flow of a 180° curved pipe by using PIV measurements

Abstract

Aiming at the complex flow characteristics and the Dean vortex phenomenon in the 180° curved pipe, the internal flow field in the curved pipe were measured by using the particle image velocimetry technology, and the flow fields of the curved pipe at different sections and different Reynolds numbers were obtained. A process method based on DMD correction velocity vector is proposed to reconstruct the flow field. The results show that the low-order modes obtained by decomposing the flow field contain the main structure and most of the energy in the flow field. Therefore, the reconstructed flow field can more accurately restore the real flow field. At the same time, vortical patterns of Dean flow at the different Reynolds number in the 180° curved pipe were analyzed, and it is found that the Dean vortex gradually moves from the inside and outside of the curved pipe to the top and bottom with the increase of Reynolds number, and the Dean vortex shape is the most obvious at each Reynolds number at Section 2. Graphical abstract: [Figure not available: see fulltext.] © 2023, The Visualization Society of Japan.