ABSTRACT The current geometric designs of fish guidance structures with vertical bars for run-of-river hydropower plants result in high head losses and asymmetric turbine admission flow. To address these issues, we develop innovative curved bar designs and experimentally investigate different rack configurations with curved bars in a laboratory flume. The present paper (Part II) focuses on the hydraulic performance of the novel curved bar designs with regard to flow fields, while the companion paper (Part I) reports the results on the head losses. The detailed flow fields obtained by 3D velocity measurements show that the curved bars promote flow conditions favourable for both fish guidance and turbine operation. The flow straightening effect of the curved bars leads to quasi-symmetrical turbine admission flow and reduced head losses. The findings are discussed with regard to fish protection and guidance, and optimal engineering application.

中文翻译：

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带弯曲杆的鱼引导结构的水力性能——第 2 部分：流场

摘要 目前，径流式水电站的带垂直杆的鱼引导结构的几何设计导致高水头损失和不对称的涡轮机进入流量。为了解决这些问题，我们开发了创新的弧形杆设计，并在实验室水槽中实验性地研究了带有弧形杆的不同机架配置。本论文（第 II 部分）侧重于新型弯杆设计在流场方面的水力性能，而配套论文（第 I 部分）则报告了水头损失的结果。通过 3D 速度测量获得的详细流场表明，曲线条促进了有利于鱼引导和涡轮机运行的流动条件。弯曲杆的流动矫直作用导致准对称的涡轮进气流和降低的水头损失。