Numerical simulation of fluidelastic instability of multispan tubes partially exposed to crossflow

The onset of fluidelastic vibration of multispan tubes partially exposed to crossflow has been studied numerically by the equivalent velocity approach based on natural mode shapes, and resonant response shapes, and by the vibratory velocity- and displacement- coupled harmonic response approach. The numerical studies were preformed using the ABAQUS-EPGEN finite element computer code with a post-processor based on the eigenvalues and eigenvectors of the system. An iterative procedure, based on the steady-state response of the fluidelastically coupled system was developed to determine critical flow velocities. The results are reported for each of the theoretical approaches and compared with available experimental data. The results based on the four theoretical approaches differ very little from each other and are generally in good agreement with experimental data