Matt Turner visited the University of Durham on Friday 31 January to give a talk in the Numerical Analysis Seminar.  The title of the talk was “Fluid sloshing and dynamic coupling”.

A moving vessel carrying a fluid can give rise to a wide range of complex and beautiful fluid motions. On the other hand, the motion of the interior fluid induces forces and moments on the vessel which can lead to unintended vessel motions and these motions could even lead to a destabilization of the vessel dynamics. One of the simplest experiments which demonstrates the fluid-vessel interaction is Cooker’s pendulous sloshing experiment.

This experiment consists of vessel with a rectangular cross-section which is partially filled with an inviscid, incompressible fluid and is suspended by two cables. The centre of mass of the system is allowed to rotate in a vertical plane, while the tank bed remains horizontal. This generates an irrotational fluid motion in the vessel.

In Matt’s talk he showed that this experimental setup contains an internal 1:1 resonance where the anti-symmetric fluid sloshing modes, which induce the vessel motion, have exactly the same frequency as the symmetric sloshing modes which occur in a stationary vessel. He showed that an exchange of energy between the vessel dynamics and the fluid motion can occur close to the 1:1 resonance when nonlinearity is considered.