The wake of a freely flying European Starling

One of the fun things about working at a university is the continual series of lectures, presentations, and seminars about current research. Today in the Department of Mechanical and Materials Engineering, a paper was presented on aerodynamics, an area in which Western does a lot of work. The paper is titled A case study of unsteady wings: the wake of a freely flying European Starling (Sturnus vulgaris), by Kirchhefer et al.

It’s solid, practical research in aerodynamics:

In recent years, an increasing interest in developing unmanned aerodynamic vehicles (UAVs) has prompted research on the related aerodynamic phenomena. This branch of aerodynamics focuses on low Reynolds number wings, of a variety of shapes, moving unsteadily through a fluid.

And what better way to study such processes than on existing systems that behave similarly? So they turn to birds:

As living organisms, birds are subject to selective pressures. As such, one may assume they operate their wings in a manner that is highly efficient. Although this notion is supported by the tendency of birds, as well as many other animals, to operate in a Strouhal number range (0.2-0.4)
of robustly high efficiency (Anderson et al., 1998; Taylor et al., 2003) . . .

But they note that working with live animals ‘presents a difficulty’ or two. Not the least of which seems to be safety:

Due to the powerful laser operating within a few chord lengths of the bird’s tail, two precautions were taken to ensure the bird’s safety. Goggles made of a flexible, optically dense, polymer material were designed to protect the bird’s vision as well as reduce the potential of the lightsheet frightening the bird. After an accommodation period in a cage of fifteen minutes to half an hour, the bird would fly normally in the tunnel while wearing the goggles.

(Emphasis mine.) Somewhere in a department full of sensible, practical, mechanical engineers, there is someone whose job it is to design tiny goggles for little birds to wear in the wind tunnel. So they’re not hurt by the giant laser, of course.

This is yet another example of why universities are wonderful.

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