Generation of an isolated vortex gust through a heaving and pitching foil

TL;DR

This paper presents a method to generate controlled isolated vortex gusts using a rapidly pitching and heaving airfoil, facilitating systematic studies of vortex-airfoil interactions in simulations and experiments.

Contribution

A novel approach for generating vortex gusts with prescribed properties through a symmetric airfoil's rapid pitching motion, applicable to both numerical and experimental setups.

Findings

Vortices propagate nearly parallel to the flow with an oblique wake extension.

Consistent trends in vortex characteristics across different Reynolds numbers and conditions.

The aerodynamic influence of the vortex wake diminishes over time, indicating transient effects.

Abstract

This study introduces a vortex gust generation method for isolated vortices impacting a downstream airfoil that is applicable to both numerical simulations and experiments. The vortex gust is generated by a symmetric airfoil undergoing a rapid pitching maneuver during a prescribed heaving motion. The resulting vortices propagate along trajectories nearly parallel to the incoming flow, while the associated wake extends obliquely from the vortex core. Despite differences in Reynolds number, rapid pitching duration and detailed vortex structure between simulations and experiments, consistent trends are observed in how the vortex rotation orientation, strength, and position vary with the prescribed motion parameters. Analysis of the lift response of the downstream airfoil shows that the aerodynamic influence associated with the wake does not persist over extended time scales. These results demonstrate that the proposed method enables the controlled generation of vortex gusts with prescribed characteristics, providing a flexible approach for systematic studies of vortex-airfoil interaction.