Sky Dancer: A Complex Fluid-Structure Interaction

Exact geometric theory for flexible, fluid-conducting tubes

“…In addition, a connection with the so-called follower-force approach, and some lively criticism of the latter, is available in [9]. While this theory had shown good agreement with experiment on some levels [20,11,5], there are several reasons for improvement. For example, that theory, having divergent velocities of disturbances for the short-wavelength limit, is difficult to use for the prediction of long-term dynamics in the unstable regime.…”

Divergence instability in an air-conveying soft tube: Analysis of static zig-zag shapes

“…Flores-Castillo and Cros (2009) reproduced a reduced model of sky dancer in their laboratory and described how a fold propagates along the soft tube as it is pushed away from the pump exit thanks to the air pressure. Moreover, the critical velocity above which the sky dancer fluctuates (Cros et al, 2012) is higher than the predicted value by ; this result suggests that a different mechanism is involved in the sky dancer stability. Finally, Orozco-Estrada et al (2020) analyzed the intermittent regime which develops.…”

Deformations of an elastic pipe submitted to gravity and internal fluid flow

“…Firstly, we wonder in what extend a compliant tube can be deformed by a fluid flow. Above a critical flow velocity, the free end of an elastic pipe becomes unstable (Bourrières, 1939;Cros et al, 2012;Doaré and de Langre, 2002;Castillo Flores and Cros, 2009). Particularly, Gregory and Païdoussis (1966) studied the critical velocity U c above which the instability occurs.…”