Fluid-structure interaction during artificially induced water hammers in a tube with bend – experiments and analyses

Experimental and numerical investigations of artificial water hammers in a pipe with a bend are presented. At FZR a cold water hammer test facility was used to measure the fluid pressures and the pipe wall stresses occurring during water hammers. The finite element code ANSYS® was used for the numerical analysis of the experiments. The focus was put on the local distributions of pressure and stress. It could be shown that the fluid pressure and pipe wall stress exhibit complex 3-dimensional structures, which is a consequence of the fluid-structure interaction. The highest stresses occur in the pipe bend. The pressure peak is lower than predicted by the extended Joukowsky formula.