Q8-1 Improved Screening of Fluidelastic Instability Using Mode Shape Weighting

K. J. Farrell

Because the velocity and span lengths are not generally uniform across a heat exchanger tube, mode shape weighting of the crossflow velocity is necessary to evaluate the potential for fluidelastic instability accurately. While this evaluation is easily accommodated in a finite element analysis, the application in a vibration screening analysis is more difficult. However, observations of modal amplitude behavior for multispan tubes have led to an approximation of modal weighting in Xist™ that increases the accuracy of the screening for fluidelastic instability.