Vendredi 24 janvier à 11h00, salle des séminaires IRPHE
Abstract: Kinetic facades by environmental artist Ned Kahn have recently been the subject of an in-depth scientific study. These building facades are made up of thousands of small aluminum panels, a few centimeters in size, that swing harmoniously in the wind, creating regular wave-like patterns reminiscent of fluttering flags or ocean waves. Researchers analyzed numerous videos of these artworks available on YouTube and Vimeo and conducted wind tunnel experiments with a 1D chain of millimeter-sized panels to uncover the physical mechanisms behind the unique patterns observed in these installations.
Their analysis revealed that at low wind speeds, the response of each pendulum is primarily determined by resonance at its natural oscillation frequency. Conversely, at higher wind speeds, the response is dominated by turbulent pressure fluctuations carried by the wind across the facade. These fluctuations generate waves that propagate along the chain of pendulums, creating the characteristic undulating patterns seen in Kahn’s works.
The study, titled Large-scale turbulent pressure fluctuations revealed by Ned Kahn’s artwork, published in Physical Review Fluids on November 14, 2024, sheds light on the invisible forces that give rise to the shimmering, ever-evolving patterns of kinetic facades. The researchers identified two branches of dispersion relations corresponding to distinct wave propagation modes along the pendulum chains. This discovery provides a deeper understanding of the interaction between architectural structures and natural phenomena, paving the way for future designs that harmoniously integrate art and science.