Fluiddynamic waterhammer simulations with consideration of fluid-structure interaction

The design rules for pipe systems of nuclear installations require that also fluid dynamic loads have to be examined (KTA 3201 and 3211, RSK-L. 4.1.1-3,4). These loads are the result of transient pressure changes, developing due to the acceleration and slow down of the fluid masses. In the past, results were obtained only from fluid dynamic calculations or simulations without consideration of the fluid-structure interaction (FSI) or only by considering the structural influence to the fluid. In the last decade, one-dimensional programs were introduced to simulate the influence of the structure to the fluid but not to explore the feedback from the fluid to the structure (Borchsenius and Bornemann). The topic of this project is to investigate the influence of the dynamic fluid-structure interaction in pipes on the pressure in the fluid and on the reaction loads on the structure to show whether the commonly used formula are conservative or not and when it is necessary to consider the FSI especially with fully-coupled 3D-Codes. The project this report is based on is included in the initiative for competence maintenance in nuclear technology which is carried by the Verein Deutscher Elektrizitaetswerke e.V. (VDEW e.V.) and the German Ministry of Research (BMBF). (orig.)