Bucha Muhammad Hammad, Khan Niaz Bahadur, Uddin Emad, Riaz Hafiz Hamza, Munir Adnan, Farooq Umar, Zhao Ming, Muhammad Riaz, Jameel Mohammed, Nasir Muhammad Tauseef, Qadri M Nafees Mumtaz
School of Mechanical & Manufacturing Engineering (SMME), National University of Sciences and Technology (NUST), Islamabad, Pakistan.
Mechanical Engineering Department, College of Engineering, University of Bahrain, Isa Town, Bahrain.
PLoS One. 2025 Jul 17;20(7):e0327916. doi: 10.1371/journal.pone.0327916. eCollection 2025.
Due to dwindling energy reserves and the cost-effectiveness of installation, the global trajectory is shifting towards renewable energy sources as a proficient means of energy acquisition. Among these sources, hydropower stands out as it harnesses the kinetic energy of oceanic water flow to generate power. Various studies have harnessed vortex-induced vibrations (VIV) to generate power from a piezoelectric eel, showcasing the diverse applications of this technology. The present experimental study further explores this technology and investigates the effect of surface roughness of cylindrical bluff body on the energy harvested by piezoelectric eel using a low-speed water tunnel. The experiments were performed at four different roughness values (Ks/D) namely 2.21, 4.07, 9.85, and 13.97 microns for the cylinders with diameters of 25, 27, 27.2, and 27.5 mm, respectively. The Reynolds number in the present study is fixed at 8690. A total of hundred case studies were performed to analyze the effect of the surface roughness of the cylinder on energy harvesting performance from the eel. The flapping frequency, amplitude, and optimal power of the rough cylinders were analyzed and compared with that of smooth cylinders experimentally, and the optimum point ([Formula: see text]) in terms of power was attained. Increased surface roughness significantly reduced power output, flapping frequency, and amplitude. The smoothest cylinder (Ks/D = [Formula: see text]) produced the highest power (52.325 µW), while the roughest (Ks/D = [Formula: see text]) resulted in a 6.26% decrease in power (36.4 µW), along with reductions of 4.5% in flapping frequency and 20% in amplitude. By increasing the surface roughness of the bluff body, the lock-in region decreases and as a result, the harvested power from that bluff body is reduced. Moreover, the power also decreased by increasing the distance between the cylinder and eel both in the x- and y-direction. The results of the current study provide deeper insights into the effect of surface roughness on energy harvesting from piezoelectric eel behind cylindrical bluff body, that are essential for the development of efficient energy harvesting systems. The findings of this study would be useful for the design of piezoelectric eel-based energy harvesting devices in marine environments.
由于能源储备的减少以及安装的成本效益，全球能源发展趋势正转向可再生能源，将其作为一种高效的能源获取方式。在这些能源中，水力发电尤为突出，它利用海水流动的动能来发电。各种研究利用涡激振动（VIV）从压电鳗鱼发电，展示了这项技术的多样应用。本实验研究进一步探索这项技术，并使用低速水洞研究圆柱形钝体表面粗糙度对压电鳗鱼所获能量的影响。实验针对直径分别为25、27、27.2和27.5毫米的圆柱体，在四个不同的粗糙度值（Ks/D）下进行，即2.21、4.07、9.85和13.97微米。本研究中的雷诺数固定为8690。总共进行了一百个案例研究，以分析圆柱体表面粗糙度对压电鳗鱼能量采集性能的影响。通过实验分析并比较了粗糙圆柱体与光滑圆柱体的拍打频率、振幅和最佳功率，并得出了功率方面的最佳点（[公式：见原文]）。表面粗糙度增加显著降低了功率输出、拍打频率和振幅。最光滑的圆柱体（Ks/D = [公式：见原文]）产生的功率最高（52.325微瓦），而最粗糙的（Ks/D = [公式：见原文]）导致功率下降6.26%（36.4微瓦），同时拍打频率降低4.5%，振幅降低20%。通过增加钝体表面粗糙度，锁定区域减小，结果是该钝体采集的功率降低。此外，在x和y方向上增加圆柱体与鳗鱼之间的距离也会使功率降低。本研究结果为圆柱形钝体后方压电鳗鱼能量采集过程中表面粗糙度的影响提供了更深入的见解，这对于高效能量采集系统的开发至关重要。本研究结果将有助于海洋环境中基于压电鳗鱼的能量采集装置的设计。
