Theoretical and Experimental Study for Free Vibration for Cantilever Plate Partially or Totally Submerged in Fluid

Abstract

In this thesis the dynamic characteristics (natural frequency and mode shape) of cantilever plates was studied when they immersed partially or totally in the fluid. The viscosity, density and compressibility of the fluid were taken into account in the theoretical analysis by using the (ANSYS Package) which mainly depends on the (Finite Element Method) in the analysis; by execute interaction between fluid and plate in the interface surface. The (damping analysis) method was used to analyze the new fluid-plate system; this new system is different in its characteristics when compared with the characteristics of the fluid or plate individually. The results were compared with the dry plate characteristics, which were obtained by using the same analyses package, but in this case the (modal analyses) method was used.The natural frequencies and mode shapes for cantilever plates with different aspect ratios immersed in different ratios in fluid were obtained. The effects of submerging ratio and aspect ratio on the plate's dynamic characteristics theoretically and experimentally were investigated. The results showed that, the submerged of cantilever plate in fluid reduce the natural frequency, and this depends on the fluid type, submerged ratio and aspect ratio, and the density is the most influential fluid property on the dynamic characteristics of the plate.