Instabilities of a Spatial System of Articulated Pipes Conveying Fluid

A spatial system of two articulated pipes conveying fluid is examined analytically and experimentally. As the flowrate is increased, stable equilibrium is studied for either divergence (static buckling) or by flutter (oscillations with increasing amplitude), depending upon the value of an angle beta which measures the 'out-of-planeness' of the system. It is found that in the range between zero and 90 degrees there exists a transition value of beta below which stability is lost by flutter and above which stability is lost by divergence.