A numerical investigation of sweep effects on turbulent flow over iced wings

TL;DR

This paper uses an advanced simulation method to analyze how sweep angle affects turbulent flow and ice accretion on wings, revealing complex vortex behavior and unsteady aerodynamics driven by spanwise flow.

Contribution

The study introduces an improved AMD-IDDES simulation approach incorporating anisotropic dissipation, providing more accurate insights into iced swept wing aerodynamics compared to traditional methods.

Findings

Sweep angle induces strong spanwise flow altering vortex development.

Shear layer separation driven by Kelvin-Helmholtz instability dominates unsteady response.

Wingtip effects are secondary but influence vortex frequency.

Abstract

This study employs an improved delayed detached eddy simulation (AMD-IDDES) method to investigate the flow characteristics of an iced swept wing. The AMD-IDDES approach incorporates an anisotropic minimum-dissipation (AMD) model into the traditional IDDES framework to better account for local flow anisotropy and energy dissipation characteristics. The method is validated against the traditional IDDES approach, and the results show that AMD-IDDES more accurately captures the evolution of vortices and separated shear layers. Compared with an iced straight wing, a swept wing exhibits distinct aerodynamic behavior driven mainly by the sweep angle. The sweep angle induces strong spanwise flow, which reshapes the separation region and transforms the flow from two-dimensional to three-dimensional. This spanwise motion significantly alters vortex development and enhances the complexity of the unsteady flow. The shear layer separation, initiated by a Kelvin-Helmholtz instability, dominates the unsteady aerodynamic response. Although wingtip effects remain secondary, their interaction with the leading-edge vortex still contributes to lowering the dominant frequency. Overall, this study highlights that the aerodynamic forces of an iced swept wing are primarily governed by sweep-induced spanwise flow and associated shear layer dynamics, with minimal influence from the root and tip regions.