垂直式靜水池之力學分析與捲氣模擬

NUMERICAL INVESTIGATIONS FOR AIR-ENTRAINMENT TRANSLATIONS, PRESSURE DISTRIBUTIONS AND SHEAR-STRESS VARIATIONS OF FREE OVERFALL IN A VERTICAL DROP POOL

10.6652/JoCICHE.201706_29(2).0007

邱家麟(Chia-Lin Chiu)；范佳銘(Chia-Ming Fan)；欉順忠(Shun-Chung Tsung)

自由跌水 ； 滑流 ； 水舌流 ； 週期性振盪流 ； free overfall ； nappe flow ； periodic oscillatory flows ； skimming flow

中國土木水利工程學刊

29卷2期（2017 / 06 / 01）

127 - 137

繁體中文

自由跌水落入垂直式靜水池是常見的水利工程現象，根據水流流量與池內幾何尺寸不同，流場大致上可以分為滑流、週期性振盪流與水舌流這三種不同特性的流況。在流場週期振盪的過程中，靜水池周遭結構受到滑流與水舌流反覆撞擊的流體作用力大小，是相關工程強度設計中重要的考慮因素；而大量的空氣被捲入水中產生氣泡則是另一個非常複雜而有趣的物理現象。本研究利用納維耳－史托克斯模式進行這三種流場的數值分析，針對靜水池底部與下游尾檻表面所受到的流體壓應力與剪應力分別進行討論，並且追蹤水中捲氣在週期振盪過程中的傳輸變化行為。

The flow regimes of free overfall in a vertical drop pool can be mainly classified into skimming, nappe and periodic oscillatory flows depending upon different discharges and pool dimensions. A very interesting phenomenon is lots of air entrained into the water flow as little foam or bubbles during the oscillatory process. In addition, investigation of distributions of pressures and shear stress acting on the solid surface is another important concern for the design strength of such hydraulic structure. In this study, the Navier-Stokes simulations are implemented to investigate the effect of various plunge pool lengths on the flow conditions with a fixed subcritical approach flow. To characterize the flow regimes of flow over a drop pool, special attention is given to the air-entrainment translation and the pressure with shear-stress distribution along the pool bottom and the sill surface.

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