On the capability of structural-acoustical FSI simulations to predict natural frequencies of rotating disk-like structures submerged in a heavy fluid

Predicting natural frequencies of rotating disklike structures submerged in water is of paramount importance in the field of hydraulic machinery, since the dynamic response of disks presents similarities to the dynamic response of pump-turbine runners. Well-known computational methods, such as structural-acoustical fluid–structure interaction (FSI) simulations, are perfectly capable to predict the added mass effects of standing submerged disks. However, the capability of these simulations to predict the effect of rotation in the natural frequencies of submerged disks has not been investigated. To obtain adequate results, the relationship between the disk rotation and the fluid rotation has to be introduced in the simulation model to consider the effects of the surrounding flow and the transmission within rotating and stationary frame. This procedure is explained and discussed in this technical brief comparing analytical, numerical, and experimental results.

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