Numerical and Experimental Study on the Bragg Reflection of Water Waves by Multiple Vertical Thin Plates

Abstract

The Bragg reflection of water waves by multiple vertical thin plates is investigated numerically and experimentally. The problem of surface gravity wave interaction with multiple vertical thin plates is formulated mathematically under the assumption of linear water wave theory. Numerical results of the reflection and transmission coefficients are obtained based on the dual boundary element method and compared with the results in the literature. The characteristics of Bragg reflection are represented by the occurring condition, the primary reflection coefficient and the effective bandwidth. The effects of the number, the immerged depth and the spacing of the plates on the characteristics of Bragg reflection are further analyzed systematically. Model experiments are conducted and the experimental results are used to compare with the numerical results of Bragg reflection. This study can provide guidance on the design of multiple vertical thin plates as effective breakwaters by taking advantage of Bragg reflection.

Directional Wave Scattering Distribution Modes Analysis and Synthesis of Random Ocean Media Roughness for SAR Electromagnetic Interactions Using Feature Fusion in Dynamic Sea States: A Survey

“…However, the major drawbacks of these empirical formulations lie in their absence of domain categorization and limited evaluation scenarios [41], [42], as no field experiments have been conducted to measure the entire wavelength range to date and there is no widely accepted WFS formula that covers the entire domain [43]. To address these limitations and offer validations, numerical methods covering a wide range of wavelengths have been introduced, each focusing on solving a specific problem [44]- [47]. However, given the approximate nature of all numerical methods [48], the modeling procedure must strike a balance between accuracy, complexity, and dimensionality [49].…”

“…Specifically, for reliable numerical modeling of ROM, it is crucial to effectively characterize the stochastic scattering properties of these nondeterministic media by incorporating a statistical distribution of spectral components that reflects the trade-off between approximation and dimensionality [30], [39], [42], [46]- [51]. In this context, numerical models are utilized to explore the distinctive physical characteristics of ROM, particularly in surface roughness patterns, a phenomenon challenging to fully replicate through experimental formulations, especially amidst wind-waves and specific oceanic conditions, commonly referred to as sea states [44]- [47], [52]- [54]. As a result, numerical modeling of ocean surface roughness involves analyzing spectral scattering contributions from the ROM's physical state and dynamics [30], [55], characterized by the statistical distribution of WFS under various sea states [37], [55]- [57], determined by wind speed and direction [52], [55], [58], [59], holding scientific significance, especially in ocean probing [59]- [62].…”

“…It is worth noting that, despite anecdotal evidence either on the sole use of numerical methods or on data interpretations of ocean surface [38], [40], [47], [56], [58], [62]- [65], a survey article addressing the numerical modeling of ROM roughness and its structural interpretation [66], [67], with a focus on the stochastic distribution of WFS under varying sea state conditions, has yet to be a published. More specifically, although most studies have focused on the physical formulation of WFS [64], [68]- [70], addressing specific problems in distinct domains primarily using either 1D formulas or 2D simulations [71]- [73], there is currently a gap in the literature regarding a comprehensive survey on the 3D modeling of ROM through WFS synthesis and the analysis of roughness patterns in response to sea states [37].…”

“…It encompasses a range of surveys, including numerical modeling of ROM, synthesis of surface texture, analysis of roughness patterns and fractal fluctuations, investigation of SAR texture electromagnetic interactions, and the generation of an optimal reference roughness model. The proposed approach reduces the reliance on ocean empirical approximations and field observations [11], [35], [38], as well as the limitations of formulations [6], [22], such as dimensionality [30], [50], [55], large-scale formulations [3], [41], modulation effects [53], [68], [74], stochastic distributions [19], [42], [76], and wavenumber complexities [36], [47], [101]. In a broader context, this research extends the groundwork laid by [9], [12], [24]- [27], [29], [30], [34], [37], [42], [46], [48]- [50], [55]- [62], [64]- [65], [67], [68], [73]- [78], [80], [82], [86], [87],…”

Experimental study on the hydrodynamic characteristics of a Bragg breakwater with triple vertical plates

“…Shin and Cho [27] studied theoretically and experimentally two vertical thin plates on the free surface, and found that the wave diffractions depended on the relationship between the wavelength and the spacing of the two adjacent IOP Publishing doi:10.1088/1757-899X/1288/1/012042 3 plates, and the peaks of reflection and transmission coefficients became sharper and narrower at the resonance regions. Ding et al [28] investigated numerically and experimentally the multiple vertical thin plates by varying the number, the immerged depth and the spacing of the plates, and analyzed the characteristics of Bragg reflection involving the occurring points, the primary reflection coefficients and the effective bandwidths.…”