Scaling trends of bird's alular feathers in connection to leading-edge vortex flow over hand-wing.

ABSTRACT: An aerodynamic structure ubiquitous in Aves is the alula; a small collection of feathers muscularized near the wrist joint. New research into the aerodynamics of this structure suggests that its primary function is to induce leading-edge vortex (LEV) flow over bird's outer hand-wing to enhance wing lift when manuevering at slow speeds. Here, we explore scaling trends of the alula's spanwise position and its connection to this function. Specifically, we test the hypothesis that the relative distance of the alula from the wing tip is that which maximizes LEV-lift when the wing is spread and operated in a deep-stall flight condition. To test this, we perform experiments on model wings in a wind tunnel to approximate this distance and compare our results to positional measurements of the alula

SUBMITTER: Linehan T 

PROVIDER: S-EPMC7220954 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature