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在湖泊、水库和海洋中均有异重流现象发生,异重流总会卷吸周边流体进入流动。通过理论分析研究卷吸系数,指出必须不断有一定比率的周边流体被卷吸进入流动,异重流的流速才能保持恒定而不是不断加速。根据这一原理,推导出卷吸系数方程,并且说明了卷吸系数不仅与理查逊数有关,也与密度分布和流速分布密切相关,后两者与流动床面的糙度密切相关。卷吸系数大意味着异重流快速与清水掺混,从潜入点运行较短的距离后密度就会降低到临界密度差之下而停止。由此推导出异重流可以运行的最大距离,与异重流初始流量和密度差成正比,与卷吸系数成反比。小浪底水库的实测资料也说明,在水库里只有初始流量和含沙量较高的异重流才能到达坝前。
In the lakes, reservoirs and oceans have different heavy flow phenomenon occurs, different heavy flow will always entrain the surrounding fluid into the flow. Through theoretical analysis and study of the suction coefficient, it is pointed out that the peripheral fluid must constantly be entrained into the flow with a certain ratio, and the flow velocity of the heavy flow can be kept constant rather than continuously accelerated. According to this principle, the equation of entrainment coefficient is derived, and the entrainment coefficient is not only related to Richardson number, but also closely related to the density distribution and velocity distribution. The latter two are closely related to the roughness of the fluidized bed. A large coefficient of entrainment means that the heavy flow is quickly mixed with fresh water, and after a short distance from the point of entry, the density drops below the critical density difference and stops. From this we can deduce that the maximum distance at which heavy flows can operate is proportional to the initial flow rate and density difference of isoparametric flows and inversely proportional to the entrainment coefficient. Xiaolangdi reservoir measured data also shows that only the initial flow in the reservoir and the sediment concentration of heavy flow before they can reach the dam.