Numerical modeling of elastic waveguides coupled to infinite fluid media using exact boundary conditions

• We present an approach to model waveguides coupled to fluid media.
• The formulation is based on the Scaled Boundary Finite Element Method.
• The effect of the fluid is modeled using boundary conditions.
• The exact boundary conditions are derived using radiation impedances.
• The proposed approach is highly efficient and stable.

The simulation of guided waves in plate structures and cylinders coupled to infinite fluids is addressed. The approach is based on the Scaled Boundary Finite Element Method. Only a straight line is discretized that represents the through-thickness direction or the radial direction. The surrounding fluid is accounted for by employing a damping boundary condition that is based on the analytical description of the radiation impedance. Since the radiation impedance is a function of the wavenumber in the waveguide, an iterative solution procedure is applied. The algorithm is highly efficient while the results are in agreement with the Global Matrix Method.