ON SOME ASPECTS OF FLUID-STRUCTURE INTERACTION IN TWO-PHASE FLOW

The paper presents a theoretical model of the fluid-structure interaction effect in two-phase inviscid flow. A time-space variation of the fluid density at the interface between a fluid and a rigid section is considered. The coupled problem is then written as a Laplace equation for the pressure with a boundary condition at the fluid-structure interface depending on the acceleration, the velocity of the structure and on the rate of change of flow density. It is shown that contrary to the homogeneous flow, the added mass operator is not symmetrical and depends on the flow through fluid density variation. The model shows also an added damping operator related to the rate of change of flow density. Added damping coefficients are found to be positive or negative, indicating the possibility of instability development into the dynamics of the structure.