VIBRATIONS OF TUBE ARRAYS IN TRANSVERSAL FLOW.

The vibrations induced in tube arrays by a transversal flow are of great practical interest because of their destructive effects especially on heat exchangers. A generation and a synchronization of vortex shedding by a transversal tube motion when its frequency approaches the shedding The study described in this paper gives important information concerning characteristic parameters of the ″lock-in″ effect (a generation and a synchronization of vortex shedding by a transversal tube motion when its frequency approaches the shedding frequency) and the whirling instability (quasi-steady forces generated by the displacements of the tubes in flow field). Tests are conducted on an equilateral pitch bundle and on several bundles with various pitches and configurations.