Propagation of acoustic waves in a coupled ice-water system for the Arctic Ocean

Propagation of acoustic waves in a coupled ice-water system for the Arctic Ocean is studied.The sea ice is seen as homogeneous as well as the water.The dispersion equation is derived by using the theory of waves in solid and liquid media.The ω-k dispersion curves are obtained by solving the dispersion equation using the bisection method,from which the phase and the group velocity dispersion curves are obtained.Numerical results show that the dispersion curves corresponding to the waves in the coupled ice-water system arise from the coupling of those corresponding to the waves in an ice layer and a water layer.The phase velocity dispersion curve corresponding to the m-th(m> 1) guided wave in the coupled ice-water system is formed from that corresponding to the second order wave in the ice layer and that corresponding to the m-th(m ≥ 1) guided waves in the water layer.Moreover,the group velocity dispersion curve corresponding to the m-th(m> 1) order guided wave has a maximum value and a minimum value.In addition,the wave structure of guided waves in the coupled ice-water system is analyzed in detail.Results show that the energy corresponding to the first order guided wave is concentrated in the ice layer and the water near the ice.The distribution of radial and axial displacement amplitude,which is corresponding to the m-th(m ≥ 2) order guided wave,along the depth direction is periodic.Moreover,the higher the order,the more complex the vibration.