A method of computation for fluid structure interaction

A method of computation for fluid-structure interaction is developed. This method is especially suitable for the response calculations of both linear and nonlinear long-time duration fluid-structure interaction problems. This approach has the advantage of applying an implicit-explicit algorithm to the fluid and structural generalized displacement variables simultaneously and a modified explicit Rational Runge Kutta operator of order two applied to the pressure variables. As a result of this implicit-explicit partitioning, the advantages of employing larger time step and the reduction of the semi-bandwidth of the discretized equations are achieved. Critical time step estimates and the computer implementation of this technique are presented. Numerical examples are also given to demonstrate this attractive addition to the repertoire of the integration methods. As a by-product of this development, an improved unconditionally stable implicit-implicit method for the analysis of coupled fluid-structure systems is introduced. The structural displacement, fluid velocity and fluid pressure are independent variables. The resulting coupled matrix equations are symmetric and "profiled.".