Showing papers on "Vortex-induced vibration published in 1976"

Experimental development of design criteria to limit liquid cross-flow-induced vibration in nuclear reactor heat exchange equipment

Abstract: An extensive series of experimental vibration tests has been conducted on tube bundles of contemporary interest in a large water tunnel. The main objective of these tests has been to develop a design criterion to limit vibration amplitudes. It has been found that the main excitation mechanisms are turbulence, some vortex shedding, and hydroelastic instability. The results of these tests are correlated and presented. It is found that the most serious excitation mechanism is hydroelastic instability. Criteria are advanced for establishing upper velocity limits based on the experimental findings. The vortex shedding mechanism is found to only be a problem for tubes in the inlet region of some bundles. Strouhal numbers associated with observed resonances are tabulated and discussed. Tube response to random turbulence has been studied for numerous bundles but is found to be of secondary significance.

Predicting flow induced vibration in U-bend regions of heat exchangers - An engineering solution

Abstract: From the standpoint of flow induced vibrations, U-bends of tubular heat exchangers constitute structurally one of the most vulnerable regions. The U-bends possess relatively low out-of-plane frequency enabling them to extract energy from the shell stream at low flow velocities. All published correlations in the literature imply the existence of a direct relationship between the flow velocities and the incidence of large ampitude tube vibrations. Hence it is important to determine the velocity profile in the U-bend region accurately. A method to obtain an engineering solution is proposed herein which may be utilized in conjunction with the available correlations to reliably predict the possibility of vibration. Determination of the flow profile may be further utilized to improve the estimates of shellside heat transfer coefficients.