丁坝下游恢复区流场初探

Study on Velocity Field near Redeveloping Region behind Groin-Like Structures

笔者的试验资料表明,丁坝下游恢复区流速分布呈自相似性。根据相似原理,二维沿水深平均Reynolds方程可转化为常微分方程,这样就得到了恢复区流速分布式。宽浅明槽中的试验表明,该流速分布式与实测值比较吻合。此外,本文还对紊动粘性系数沿水流方向的变化作了简要探讨。

Groins are used in seashore to protect banks from wave and sea erosion and also used in rivers to protect banks from erosion caused by flow concentration and attack, as well as adopted to divert or guide the flow. Hence, it is important to study the flow near the groin-like structure in engineering projects. In addition, the flow near the groin-like structure is one issue in hydraulics. It is similar to the flow near a sluice gate, a sand dune or a gate in pipe, etc.The velocity distribution near redeveloping region behined the groin-like structure is found to be self-preserving in character. The two-dimensional Reynolds' equation is transformed into an ordinary differential equation by similarity considerations, the equation of velocity distribution near redeveloping region is obtained. Values by the equation derived are in close agreement with measurements. In addition, this paper also briefly study t'he turbulent viscosity along the mean flow direction.