论文部分内容阅读
研究通过缓坡明渠短的侧向束窄段的卡克水流 (Chokedflow) ,根据能量守恒和开度 (束窄段宽与总河宽之比值 )范围很宽的试验数据 ,探求出了新的流量公式。理论推导计及发生于卡克状态下的束窄段之临界流条件。影响流量系数的开度σ、阻水构筑物形状、进水角α及相对收缩长度L 等都予以考虑 ,并用不同的研究者所做总共 1 86组卡克水流试验确定本文的流量公式的系数。分析表明 ,流量系数主要受σ的影响 ,本研究所用的σ=0 .1 2～ 0 .88,流量系数变化于 0 .2 9～ 0 .54之间。同时证明 ,阻水构筑物形状由锐角变化至圆角的流量系数(及相应流量 )变化达 1 6 % ;α由 30°至 90°,流量系数变幅 1 1 % ;L 由 0到 1 .33 ,流量系数变幅 6 %。本研究把惯用的卡克水流分析扩大到严重束窄段 ,建议公式很好地吻合先前的试验数据 ,既可应用于预估通过已知上游水深的束窄段的流量 ,又可用于卡克情况下已知相应流量而预计束窄段的上游水深。
A new method based on the experimental data of a wide range of energy conservation and opening (ratio of beam width to total river width) was obtained through the short lateral beam narrow Chokedflow formula. The theoretical derivation accounts for the critical flow conditions in a narrow section of a beam that occurs in the state of a Kake. The influence of flow coefficient σ, the shape of water blocking structure, water inflow angle α and relative contraction length L are considered. A total of 1 86 sets of kcal flow tests conducted by different researchers are used to determine the coefficient of the flow equation in this paper. The analysis shows that the flow coefficient is mainly affected by σ, σ = 0.12 ~ 0.88 used in this study, and the flow coefficient changes between 0 .29 ~ 0 .54. At the same time, it was proved that the change of the shape of the water blocking structure from an acute angle to a rounded one (and the corresponding flow rate) varied by 16%; α was from 30 ° to 90 °; the flow coefficient was varied by 11%; L was from 0 to 1.33 , The flow coefficient changes 6%. In this study, the conventional analysis of kcal flow was expanded to a severe narrow band. The proposed formula well matches the previous experimental data and can be applied both to predict the flow through a narrow section of well known upstream water depth, In the case of a known flow rate, the water depth upstream of the beam is expected.