STAGGERED SOLUTION SCHEMES FOR DAM–RESERVOIR INTERACTION

Traditionally, the dynamic reservoir effects in the dam–reservoir system are approximated using the added mass approach. The objective of this study is to develop unconditionally stable solutions for the dam-reservoir interaction problem in the time domain. The dam–reservoir system can be categorized as a coupled field system, in which two physical systems of fluid and structure interact only at the two domains interface. Two methods of staggered solution procedure are proposed for the dam–reservoir interaction. The first method, the staggered displacement method, is based on the approximation of the displacement from the structure's equation of motion. The second method, is based on the approximation of pressure from the fluid's equation of motion. Both methods are shown to be unconditionally stable when the two differential equations of the fluid and structure include damping terms. The staggered pressure method was modified for use when the equation of motion includes a diagonal mass matrix. Two different configurations of concrete gravity dams are used to investigate the accuracy and stability of the staggered displacement and the modified staggered pressure methods. The proposed staggered methods were found to be quite accurate when compared with the existing finite element solution.