FLOAT 发表于 2025-3-26 23:31:24
http://reply.papertrans.cn/24/2324/232347/232347_31.png疯狂 发表于 2025-3-27 04:11:01
,Convection—Diffusion,mber of causes by which a substance (such as salt or a waste material but also temperature) is spread out in addition to being transported with the mean flow: molecular diffusion, turbulent mixing, and (very importantly) variations of flow velocity over the river cross-section. For a detailed discus枕垫 发表于 2025-3-27 05:30:37
,Numerical Accuracy for Convection—Diffusion,s gets quite complicated, as an additional parameter (the Courant number) comes in. For practical purposes, it is often sufficient to consider diffusion and convection separately, and in that order. The procedure is then:烦扰 发表于 2025-3-27 11:20:53
Salt Intrusion in Estuaries,influence. If there is hardly any tide, the salt water will penetrate underneath the fresh river water as a “salt wedge”. Far more common is the situation where a strong tidal action takes care of a mixing process, such that the water in a particular cross-section has an almost uniform salt concentr食物 发表于 2025-3-27 17:06:38
Boundary Layers, bottom at sufficiently high velocity, sand will be picked up and carried with the flow, even though it tends to fall back. The process by which sediment particles are kept in suspension is turbulent diffusion. Just as in chapter 11, turbulence causes an effective transport from regions with high sa木讷 发表于 2025-3-27 18:04:02
Long Waves,cal formulation can be obtained by integrating the general hydrodynamic equations over the depth or over a river cross-section. To understand the principles, it is sufficient to use a very much simplified set of equations in this chapter and the next one. For completeness, some of the corresponding傻 发表于 2025-3-28 01:24:36
http://reply.papertrans.cn/24/2324/232347/232347_37.pngCalculus 发表于 2025-3-28 03:07:08
Long Waves in Two-Dimensional Areas, flood plains and similar situations. In many such cases, the wave length is so much larger than the water depth that a two-dimensional, depth-averaged mathematical model is adequate. The formulation is essentially the same as in Chapters 15 and 16, if the dependence on two horizontal coordinates .,财主 发表于 2025-3-28 07:29:08
Potential Flow,ise there is an additional, similar equation), together with the equation of continuity .The numerical solution of these equations is not discussed in this book. There are, however, certain situations in which they can be considerably simplified. Consider a quantity called the vorticity ., which is性满足 发表于 2025-3-28 12:22:24
Variational Calculus on Lie Groups,mediate between purely theoretical and experimental. It is concerned with simulation of the flow of water, together with its consequences, using numerical methods on computers. There is not a great deal of difference with computational hydrodynamics or computational fluid dynamics, but these terms a