Abstract The efficiency of a low-reflective caisson built at the Outer Port of Punta Langosteira (A Coruna, Spain), with a front-wall porosity of ≈ 5%, has been numerically investigated by means of OpenFOAM® for different chamber configurations and different sea states. The numerical model is validated with data coming from experimental tests performed on a scaled prototype. First, two different water levels, low and mean tide levels, are analysed. Results show that the caisson is inefficient when the water level inside the chamber is low, and suggest its proper installation taking into account the tidal regime of the area. For mean tide level inside the chamber, the efficiency of the caisson shows to be strongly dependent on the wave period and height. However, it is shown to be more sensitive to the period for low wave heights than for the high ones. Overall, the reflection coefficient ranged from 0.365 ( B / L c = 0.14 s, H = 0.02 m) to 0.660 ( B / L c = 0.26 s, H = 0.02 m). Alternative configurations with one and two chambers are also examined instead of three. Overall, the reflection coefficient is very high ( > 0.95) for the configuration with only one chamber. For the two and three-chambered caissons the mean reflection coefficient is similar ( ≈ 0.5) but the dispersion of the values is much higher for the two-chambered caisson, with values ranging from 0.176 to 0.794.

中文翻译：

---

多腔低反射沉箱的数值模拟

摘要 在 Punta Langosteira 外港（西班牙拉科鲁尼亚）建造的前壁孔隙率 ≈ 5% 的低反射沉箱的效率已经通过 OpenFOAM® 对不同的腔室配置和不同的腔室结构进行了数值研究。海洋状态。数值模型通过来自在缩放原型上进行的实验测试的数据进行验证。首先，分析了两个不同的水位，低潮位和平均潮位。结果表明，当室内水位低时，沉箱效率低下，并建议考虑该地区的潮汐情况，正确安装沉箱。对于室内的平均潮位，沉箱的效率显示强烈依赖于波浪周期和高度。然而，它被证明对低波高度的周期比对高波高度更敏感。总体而言，反射系数范围从0.365（B / L c = 0.14 s，H = 0.02 m）到0.660（B / L c = 0.26 s，H = 0.02 m）。还检查了带有一个和两个腔室的替代配置，而不是三个。总体而言，对于只有一个腔室的配置，反射系数非常高（> 0.95）。对于两腔和三腔沉箱，平均反射系数相似 (≈ 0.5)，但对于两腔沉箱，这些值的离散度要高得多，值范围从 0.176 到 0.794。对于只有一个腔室的配置，反射系数非常高（> 0.95）。对于两腔和三腔沉箱，平均反射系数相似 (≈ 0.5)，但对于两腔沉箱，这些值的离散度要高得多，值范围从 0.176 到 0.794。对于只有一个腔室的配置，反射系数非常高（> 0.95）。对于两腔和三腔沉箱，平均反射系数相似 (≈ 0.5)，但对于两腔沉箱，这些值的离散度要高得多，值范围从 0.176 到 0.794。