English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We perform DNS of flow over finite-aspect-ratio NACA 0015 wings tocharacterize the tip effects on the wake dynamics. This study focuses on thedevelopment of three-dimensional separated flow over the wing, and discuss flowstructures formed on the wing surface as well as in the far field wake.Vorticity is introduced into the flow in a predominantly two-dimensionalmanner. The vortex sheet from the wing tip rolls up around the free end to formthe tip vortex. At its inception, the tip vortex is weak and its effect isspatially confined. As the flow around the tip separates, the tip effectsextend farther in the spanwise direction, generating noticeable threedimensionality in the wake. For low-aspect-ratio wings, the wake remains stabledue to the strong downwash over the entire span. Increasing the aspect ratioallows unsteady vortical flow to emerge away from the tip at sufficiently highangles of attack. These unsteady vortices shed and form closed vortical loops.For higher-aspect-ratio wings, the tip effects retard the near-tip sheddingprocess, which desynchronizes from the two-dimensional shedding over themid-span region, yielding vortex dislocation. At high angles of attack, the tipvortex exhibits noticeable undulations due to the strong interaction with theunsteady shedding vortices. The spanwise distribution of force coefficients isrelated to the three-dimensional wake dynamics and the tip effects. Vorticalelements in the wake that are responsible for the generation of lift and dragforces are identified through the force element analysis. We note that at highangles of attack, a stationary vortical structure forms at the leading edgenear the tip, giving rise to locally high lift and drag forces. The analysisperformed here reveals how the vortical flow around the tip influences theseparation physics, the global wake dynamics, and the spanwise forcedistributions.

On the formation of three-dimensional flows over finite-aspect-ratio wings under tip effects