A study on leakage-flow-induced vibrations. Fluid-dynamic forces acting on the walls of a one-dimensional, narrow passage.

Abstract

In this paper, Ieakage-flow-induced vibrations are discussed in the case of a one-dimensional, narrow passage in which one of them is vibrating harmonically with a small amplitude. First, the fluid-dynamic forces acting on the walls of the tapered passage are analyzed. Second, the transfer matrix method is applied to the calculations of fluid-dynamic forces in the case of an arbitrary-shaped passage. The fluid-dynamic coefficients in the case of a tapered passage are calculated to check the accuracy of this method, and those in the case of the passage with a step are also calculated. It is found that if the cross-sectional area of the upstream passage is smaller than the downstream one, both negative fluid-dynamic stiffness and negative fluid-dynamic damping can occur in both the cases of a tapered passage and a passage with a step.