Three-dimensional mode coupling around a seamount

• Published in: Science China. Physics, mechanics & astronomy mechanics & astronomy, 2011-09, Vol.54 (9), p.1561-1569
• Main Authors: Luo, WenYu, Zhang, RenHe, Schmidt, Henrik
• Format: Article
• Language: English
• Subjects: Acoustics; Astronomy; Bathymetry; Classical and Continuum Physics; Convergence; Coupled modes; Coupling; Deep water; Diffraction; Diffusion rate; Discretization; Joining; Lobes; Observations and Techniques; Physics; Physics and Astronomy; Research Paper; Seamounts; Sound fields; Theoretical analysis; Three dimensional; Three dimensional models; 三维问题; 收敛速度; 数值结果; 模式耦合; 正常模; 水环境; 海山; 耦合模式
• ISSN: 1674-7348; 1869-1927
• DOI: 10.1007/s11433-011-4442-6

A recently developed three-dimensional normal-mode model is adopted to investigate mode coupling around a seamount in a deep water environment. As indicated by the theoretical analysis and verified by the numerical results, strong mode coupling occurs at the edge of a seamount under certain conditions. Therefore, mode coupling is critical for the investigation of the acoustic field in the presence of a seamount. In addition, the issue regarding the number of sectors assuring convergence is also presented. This issue is important in a two-way coupled-mode approach, especially for solving three-dimensional problems, because the computational effort increases dramatically with the number of sectors in representing a varying bathymetry. The theoretical analysis as well as the numerical example in this paper shows that artificial diffraction lobes form in the event that uniform discretization is used with a horizontal step size greater than half of the acoustic wavelength. However, by using ran- dom discretization instead, such artificial diffraction lobes are diffused, resulting in a faster convergence rate.