Computation of Steady-State Scattered Sound from Submerged Infinite Cylinders by a Structural Analog Method

摘要

Finite-element formulations of fluid-structure interaction problems based on the use of structural analogies have been used in a wide variety of applications. The formulations originate from analogies that can be derived between the equations of dynamic elastic motion and generalized forms of the scalar wave equation. The analogies prescribe that the fluid can be modeled with structural finite elements to which special material properties have been assigned. A particular advantage of this approach is the requirement for only a single degree-of-freedom at each field grid point to represent the scalar field variable. In this report the analog formulations are extended to steady-state plane wave scattering by infinite cylinders. Details of implementation of the formulations via the NASTRAN computer program are presented along with calculations of acoustic pressure scattered by submerged rigid cylinders, empty elastic cylinders, and elastic cylinders containing fluids bounded by interior cylinders which may be eccentric with respect to the outer cylinder. Comparison of numerical and analytic results for the rigid and empty elastic cases shows excellent agreement. (Author)