Large-Scale Turbulent Pressure Fluctuations Revealed by Ned Kahn's Artwork

The exhibits of the American environmental artist Ned Kahn incorporate the ephemeral beauty of nature such as wind and water flow. Amongst his artworks are the kinetic facades, which are composed of thousands of suspended aluminum panels, often covering the entire facade of buildings from parking to Museum. These hinged panels flap freely in the wind and form certain meso-scale dynamic patterns on the wall. We, as research scholars in fluid mechanics, got interested in the underlying physical mechanisms at play. Could we learn something about the wind turbulent fluctuations from simple visualization of Ned Kahn’s realisations?

To do so, we implemented a laboratory scale model composed of a one-dimensional chain of pendulums immersed in a wind tunnel. Using Fourier analysis of the pendulum motions, we showed that the advection speed of turbulent pressure fluctuations can be revealed, thanks to a mechanism similar to a wind-induced liquid surface deformation below the wave onset first introduced by Phillips in 1957.