Oblique Wave Trapping by a Surface-Piercing Flexible Porous Barrier in the Presence of Step-Type Bottoms

• Published in: Journal of marine science and application 2019-12, Vol.18 (4), p.433-443
• Main Authors: Behera, H., Ghosh, S.
• Format: Article
• Language: English
• Subjects: Approximation; Approximation method; Boundary value problems; Electrical Machines and Networks; Elevation; Engineering; Geotechnical Engineering & Applied Earth Sciences; Incidence angle; Machinery and Machine Elements; Mathematical analysis; Offshore Engineering; Piercing; Porosity; Power Electronics; Reflectance; Reflection; Research Article; Rigid walls; Rigidity; Trapping; Water depth; Water waves; Wave forces; Wave number; Wave trapping
• ISSN: 1671-9433; 1993-5048
• DOI: 10.1007/s11804-018-0036-2

The present study deals with the oblique wave trapping by a surface-piercing flexible porous barrier near a rigid wall in the presence of step-type bottoms under the assumptions of small amplitude water waves and the structural response theory in finite water depth. The modified mild-slope equation along with suitable jump conditions and the least squares approximation method are used to handle the mathematical boundary value problem. Four types of edge conditions, i.e., clamped-moored, clamped-free, moored-free, and moored-moored, are considered to keep the barrier at a desired position of interest. The role of the flexible porous barrier is studied by analyzing the reflection coefficient, surface elevation, and wave forces on the barrier and the rigid wall. The effects of step-type bottoms, incidence angle, barrier length, structural rigidity, porosity, and mooring angle are discussed. The study reveals that in the presence of a step bottom, full reflection can be found periodically with an increase in (i) wave number and (ii) distance between the barrier and the rigid wall. Moreover, nearly zero reflection can be found with a suitable combination of wave and structural parameters, which is desirable for creating a calm region near a rigid wall in the presence of a step bottom.