Analysis of coupled-mode flutter of pipes conveying fluid on the elastic foundation

The governing equation of solid-liquid couple vibration of pipe conveying f luid on the elastic foundation was derived. The critical velocity and compl ex frequency of pipe conveying fluid on Winkler elastic foundation and two- parameter foundation were calculated by po,ver series method. Compared,with pipe without considering elastic foundation, the numerical results show th at elastic foundation can increase the critical flow velocity of static ins tability and dynamic instability of pipe. And the increase of foundation pa rameters may increase the critical flow velocity of static instability and dynamic instability of pipe, thereby delays the occurrence of divergence an d flutter instability of pipe. For higher mass ratio beta, in the combinati on of certain foundation parameters, pipe behaves the phenomenon of restabi lization and redivergence after the occurrence of static instability, and t hen coupled-mode flutter takes place.