The work presented herein can broadly be categorized as a fluid-structure interaction problem. The response of a circular cylindrical structure subjected to cross flow is examined using the finite element method for both the liquid and the structure domains. The cylindrical tube is mounted elastically at the ends and is free to move under the action of the unsteady flow-induced forces. The fluid is considered to be partially compressible and viscous. The flow field is solved using a finite element method applied to the time-dependent Navier-Stokes equations. The cylinder motion is modeled using a five-degrees of freedom generalized shell element structural dynamics model. The numerical simulations of the response of the calandria tubes/pressure tubes, adjuster rod and shut-off rod of a nuclear reactor are presented. A few typical results are presented to assess the accuracy of the developed modules. Copyright © 2005 by ASME.