Meeting Abstract

P1.197  Friday, Jan. 4  Methods for quantifying disturbance force and sensitivity of simple shapes to turbulent incident air velocities KWONG, A.*; DOONG, J.; EVANGELISTA, D.; Univ. of California, Berkeley; Stanford University; Univ. of California, Berkeley devangel77b@gmail.com

Airborne objects (animals, plants, and vehicles) flying in real environments may feel disturbances from turbulence in the air they are flying through. The shape of an object and its size relative to turbulent eddies affects the magnitudes and frequencies of the disturbances felt, in other words, the sensitivity to turbulence. As part of a larger study of stability, control, and the evolution of aerial maneuvering, we quantified the sensitivity of simple two- and three-dimensional models to turbulent incident air velocity using simultaneous measurements of forces and torques and air velocities in a wind tunnel. Preliminary results compare well with theoretical predictions of the disturbances an airborne organism of a given shape might experience in a particular environment. We also found good general agreement between simplified geometric shapes and 2D animal planforms of equivalent aspect ratio. Elongated shapes with low aspect ratio are better “filters” of turbulent noise, while high aspect ratio shapes “feel” more of the turbulence. This may have important consequences for maneuvering and noise pickup from a turbulent environment as body plans evolve.