为了研究沿程水头损失与局部水头损失的变化规律,根据沿程水头损失的基本定义,推求矩形明渠消力池水跃区沿程水头损失与床面阻力系数、水跃共轭水深比、跃前断面宽高比及跃前断面水深的理论关系,提出了矩形明渠水跃区沿程水头损失及其系数和局部水头损失系数的理论公式,给出了沿程水头损失系数、局部水头损失系数和总水头损失系数的简单拟合公式。研究表明:沿程水头损失随着跃前断面水深和床面阻力系数的增大而增大,随着水跃共轭水深比和跃前断面宽高比的增大而减小;局部水头损失系数随着跃前断面弗劳德数的增大而增大;水跃区局部水头损失占比随着弗劳德数的增加而增加,弗劳德数为3时的局部水头损失占比达到90%,弗劳德数为6时的局部水头损失占比已达到95%以上。研究成果可进一步完善并丰富水跃理论体系。
Abstract
According to the definition of frictional head loss, the theoretical relations of frictional head loss with coefficient of bed resistance, conjugate depth ratio of hydraulic jump, ratio of width to height of initial section, and initial depth are deduced. The theoretical calculation equations of frictional head loss coefficient and the local head loss coefficient of free hydraulic jump in rectangular open channel are given, and the simple fitting formulas of frictional, local, and total head loss coefficients are put forward. It is shown that frictional head loss grows with the rise of the initial depth of hydraulic jump and the coefficient of bed resistance; but declines with the increase of the conjugate depth ratio and the ratio of width to height of initial section. Local head loss coefficient augments with the increasing of the Froude number of initial section. The proportion of local head loss in the total head loss becomes larger with the increase of Froude number. When Froude number is 3, the proportion of local head loss is 90%, and when Froude number is 6, the proportion of local head loss is over 95%. The research results could improve and enrich the theoretical system of hydraulic jump.
关键词
矩形明渠 /
消力池 /
水跃 /
沿程水头损失 /
局部水头损失 /
总水头损失
Key words
rectangular open channel /
stilling pool /
hydraulic jump /
frictional head loss /
local head loss /
total head loss
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