Line Shape of Boundary Transition Section of Terrain Model at Bridge Sites in Complex Mountainous Areas
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摘要:
复杂山区桥址区地形模型过渡段曲线直接影响到风洞试验或数值模拟结果的精确性,为探究桥址区地形模型边界过渡段所采用线型的合理形式,基于设置过渡段的2种思路,提出构造过渡段线型的基本原则;采用数值模拟方式对比研究3类典型过渡段线型在均匀来流流经时沿程气流分离特性、平均风速剖面、风攻角剖面及湍流动能沿程分布;分析过渡段斜率变化对流场的影响规律. 研究结果表明:平方正弦曲线在气流分离特性终同位置最大剪应力差为3.77 × 10−3 Pa,风特性过渡性能上同高度最大风速差0.09 m/s,最大湍流动能差1.46 × 10−3 J,均优于其他线型,为桥址区地形模型过渡段线型选取提供了重要参考.
Abstract:The curve of the transition section of the terrain model at bridge sites in complex mountainous areas directly affects the accuracy of the wind tunnel experiment or numerical simulation results. To study the ideal form of line shape used in the boundary transition section of the terrain model at the bridge site, the principle of constructing line shape of the transition section was put forward based on the two ideas of setting up the transition section. The numerical simulation method was used to compare the three types of typical line shapes of the transition section in terms of the flow separation characteristics, mean wind speed profiles, wind attack angle profiles, and distribution of turbulent kinetic energy along the route under the uniform flow. The influence law of the slope change of the transition section on the flow field was also explored. The results show that the sine-squared curve exhibits superior characteristics compared with other line shapes, with a maximum shear stress difference of 3.77 × 10−3 Pa at the same location in terms of flow separation characteristics, a maximum wind speed difference of 0.09 m/s in terms of transitional performance of wind, and a maximum turbulent kinetic energy difference of 1.46 × 10−3 J. These findings provide important insights for selecting the line shape of the transition section of the terrain model at bridge sites.
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表 1 计算工况
Table 1. Working conditions for calculation
计算工况 A B C D 过渡段形式 平板参考风场 兰金物体绕流流线 双曲正切函数 平方正弦函数 表 2 网格数量
Table 2. Number of grids
万个 计算工况 A B C D 网格数 244.000 390.230 100.750 281.212 表 3 不同工况首层网格$y^+ $值
Table 3. $y^+ $ values of the first layer grid under different working conditions
计算工况 $y^+ $最大值 $y^+ $平均值 A 0.7615 0.5674 B 0.9946 0.5334 C 1.3259 0.5251 D 0.9808 0.5338 -
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