The installation of a labyrinth weir as the crest of a stepped chute significantly influences the downstream chute inflow conditions relative to published design standards for more traditional crest shapes. A current study at the Utah Water Research Laboratory (Utah State University) evaluated a 10.67° trapezoidal labyrinth weir crest discharging into a 0.8H:1.0V stepped chute. To better direct flows into the chute and mitigate flow instabilities (i.e. flow surging), sloped ramps were placed in the labyrinth weir outlet cycles. The influence of six different ramp geometries are reported here relative to the weir discharge efficiency, flow surging and chute wall height requirements based on splash and spray depths. The labyrinth weir increased the spillway wall height required for flow containment by 200–300% relative to linear weir wall height predictive methods. The addition of ramps provided better flow transition into the stepped chute and reduced the required chute wall heights by up to 15%. Furthermore, ramp heights taller than half the weir wall height effectively reduced flow surging but increased local submergence, which decreased the discharge efficiency by up to 9%. Thus, an outlet cycle ramp geometry selection should be optimised by discharge efficiency, flow surging and chute wall height requirements.

中文翻译：

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迷宫堰出口坡道：管理流量不稳定性和排放效率

相对于已发布的更传统顶部形状的设计标准，将迷宫堰安装为阶梯式溜槽的顶部会显着影响下游溜槽的流入条件。犹他州水研究实验室（犹他州立大学）目前的一项研究评估了 10.67° 梯形迷宫堰坝顶排放到 0.8H:1.0V 阶梯式斜槽。为了更好地将流量引导到斜槽中并减轻流动的不稳定性（即流量涌动），在迷宫堰出口循环中放置了倾斜的斜坡。此处报告了六种不同坡道几何形状对基于飞溅和喷雾深度的堰排放效率、流量涌动和斜槽壁高度要求的影响。相对于线性堰壁高度预测方法，迷宫堰将流动遏制所需的溢洪道壁高度增加了 200-300%。斜坡的添加提供了更好的流动过渡到阶梯式溜槽，并将所需的溜槽壁高度降低了 15%。此外，斜坡高度高于堰壁高度的一半，有效地减少了流动的涌动，但增加了局部淹没，这使排放效率降低了 9%。因此，出口循环坡道几何形状的选择应根据排放效率、流量波动和斜槽壁高度要求进行优化。坡道高度高于堰壁高度的一半，有效地减少了流量涌动，但增加了局部淹没，这使排放效率降低了 9%。因此，出口循环坡道几何形状的选择应根据排放效率、流量波动和斜槽壁高度要求进行优化。坡道高度高于堰壁高度的一半，有效地减少了水流涌动，但增加了局部淹没，从而使排放效率降低了 9%。因此，出口循环坡道几何形状的选择应根据排放效率、流量波动和斜槽壁高度要求进行优化。