Accurate experimental characterization of longitudinal vortices induced by rectangular winglets is necessary to develop and validate numerical models that can predict these flows. For this aim, an experimental investigation is conducted to examine the characteristics of longitudinal vortices generated downstream rectangular winglets in fully developed turbulent channel flow. A row of rectangular winglet pairs is implemented in a parallel plate flow. Stereoscopic Particle Image Velocimetry (SPIV) is used to harvest three-dimensional (3D) instantaneous velocity fields for a Re = 4400 based on the channel’s hydraulic diameter and mean flow velocity. 3D velocity components, velocity streamlines, topologies of Γ₂ function and normalized turbulent kinetic energy downstream the winglets are analyzed. It is shown that the flow properties are disturbed, and a main vortex pair is generated in addition to induced vortices downstream the rectangular winglets. Moreover, this work provides an SPIV benchmark of the complex flow developing downstream rectangular winglet pairs, where this configuration has been widley studied using numerical simulations.

Graphical Abstract

为了开发和验证可以预测这些流动的数值模型，必须对矩形小翼引起的纵向涡旋进行准确的实验表征。为了这个目的，进行了实验研究以检查在充分发展的湍流通道中下游矩形小翼产生的纵向涡流的特性。在平行板流中实施一排矩形小翼对。立体粒子图像测速（SPIV）用于 基于通道的水力直径和平均流速来收集Re = 4400的三维（3D）瞬时速度场。三维速度成分，速度流线，Γ的拓扑₂分析了小翼下游的功能和归一化湍动能。结果表明，流动特性受到干扰，除了矩形小翼下游的诱发涡流外，还产生了一个主涡流对。此外，这项工作提供了开发下游矩形小翼对的复杂流动的SPIV基准，其中已使用数值模拟研究了这种结构。

图形概要