Influence of the boundary conditions in a friction based model of fluid-elastic instability in axial flow

A friction-based model was proposed to calculate the fluid-elastic force induced by axial flow between two surfaces with several degrees-of-freedom. Here, generals equations are written. A linearization of the averaged continuity and momentum equations across the fluid thickness, with the boundary conditions on the structure, give the expression of the fluctuating velocity and pressure. A pressure loss is introduced in the system with a localized pressure loss factor. General solutions are derived by an analytical resolution taking into account the fluctuating pressure loss factor. The fluid-elastic force expression is obtained by integration of the pressure on the structural wall. The effect of the fluctuating pressure loss on the behavior of the system (flutter and buckling instabilities) is analysed The evolution of the fluctuating velocity is determined and analysed.