A Vortex Generator Flow Model Based on Self-Similarity

TL;DR

This paper develops a self-similar vortex flow model to describe the downstream evolution of counter-rotating vortices behind vortex generators, enhancing understanding and reducing experimental costs.

Contribution

It extends previous models by incorporating self-similarity to predict vortex development downstream, based on experimental velocity profiles.

Findings

Vortices exhibit self-similar velocity profiles downstream.

The extended model accurately predicts vortex evolution.

Parametric experiments can be minimized using the model.

Abstract

The present work examines the downstream vortex evolution behind a cascade of vortex generators producing counter-rotating vortices in a boundary layer of negligible streamwise pressure gradient. For the current study, which is an extension of the model presented in [4], these parameters are all seen to vary linearly in the downstream direction. Based on the experimental observations triggered by a previous study, the vortices generated by vortex generators have been observed to be self-similar for both the axial ($u_z$) and azimuthal ($u_{\theta}$) velocity profiles. The previous model, which is based merely on $u_z$ and $u_{\theta}$ at one single downstream location, can therefore be extended to include the downstream development of the vortex using self-similarity scaling arguments. This knowledge is important for fundamental understanding as well as for the aspect of applications, for which parametric experiments can be substantially reduced in terms of required time and cost by facilitating engineering models.