As part of a master’s thesis, the critical flutter wind speed of slender bridge decks was investigated in the wind tunnel of the Steel Structures Department at the University of Kassel. Flutter is an aeroelastic phenomenon in which the coupling of multiple vibration modes leads to an unstable vibration with increasing amplitude. This occurs when the so-called critical wind speed is exceeded.

The critical wind speed is determined using aeroelastic parameters, which are established through decay tests conducted at various wind speeds. As part of the master’s thesis, a script was programmed to evaluate these decay tests.

The video shows a “flat plate” model exposed to a constant wind speed above the critical wind speed. It is clearly visible how the vibration amplitude continues to increase even though the wind speed remains constant.