Experimental Study on Regular an‎d Irregular Wave Transmission Over Submerged Breakwaters

7/29/2026 12:00:00 AM

Submerged breakwaters are among the most important coastal protection structures, playing a crucial role in reducing wave energy an‎d safeguarding coastlines. These structures, by interacting directly with waves, influence processes such as wave transmission, reflection, an‎d energy dissipation. The design an‎d performance of submerged breakwaters are highly dependent on structural parameters such as the crest width an‎d relative crest height, as well as hydrodynamic conditions such as wave steepness an‎d wave height. In this study, the effects of various structural an‎d hydrodynamic parameters on wave transmission through submerged breakwaters were investigated. The experiments were conducted using physical models in a flume with a length of 17.5 meters, a width of 0.94 meters, an‎d variable water depths. Three types of breakwaters were tested under regular an‎d irregular waves: rubble-mound structures without armor, rubble-mound structures armored with Accropodes, an‎d rubble-mound structures armored with geobags. The results showed that the relative crest height is the most influential parameter affecting the wave transmission coefficient. Generally, rubble-mound breakwaters without armor an‎d those armored with Accropodes exhibited similar wave transmission behavior. In contrast, breakwaters armored with geobags demonstrated distinct behavior due to the lower permeability of the armor layer, showing greater dependency on crest width an‎d relative crest height. At lower water depths, breakwaters with geobag armor had lower wave transmission coefficients. However, as the relative crest height decreased, the wave transmission coefficient increased. Wave steepness had a negligible effect on wave transmission, with steeper waves exhibiting lower transmission coefficients due to shorter wavelengths an‎d greater interaction with the structure. Additionally, the relative crest width significantly influenced wave transmission in impermeable armored structures, while an increase in relative crest width reduced wave transmission in geobag-armored structures. Regarding wave reflection, breakwaters armored with geobags showed higher reflection coefficients compared to the other two structures, owing to the lower permeability of the armor layer. Crest width had a negligible effect on wave reflection, but the permeability of the armor layer an‎d the relative crest height played key roles in altering the reflection coefficient. Wave breaking near the crest also contributed to increased reflection. In terms of energy dissipation, geobag-armored breakwaters exhibited the highest energy dissipation, while rubble-mound breakwaters without armor an‎d those with Accropodes showed lower energy dissipation. Increasing the crest width in geobag-armored structures enhanced energy dissipation, but this effect was negligible in the other two structures. The findings of this study provide a valuable reference for the design of submerged breakwaters, with a focus on controlling wave transmission an‎d improving structural stability under various hydrodynamic conditions.

موج‌شكن مستغرق , عبور موج , ضريب عبور , عمق نسبي تاج , نفوذپذيري آرمور , مدل فيزيكي

Submerged breakwater , wave transmission , Transmission coefficient , relative crest height , armor permeability , Physical Model

Marouei

Dr. Siadatmousavi