河工模型阻力相似的研究

 本文以长江葛洲坝工程宜昌工地的坝区泥沙模型为例,研究了模型水面线相似、糙率、阻力沿横向分布等的相似问题以及模型是否处于阻力平方区间题等。通过研究,认为阻力相似是河工模型的重要相似条件,但是较大比尺的正态模型一般并不处于阻力平方区,不能达到理论上严格的阻力相似要求。在此情况下,通过验证试验,只要做到模型与原型基本相似,水面线的偏离处于要求范围内,流速沿断面的分布基本上与原型一致,这样就可以保证试验成果的可靠性。

Criterion for Resistance Similarity in River Model

Based upon the Yichang sediment model of dam region at Gezhouba Project, this paper analyzes the similarity problem on water surface profile , roughness and transverse distribution of resistance as well as that of whether or not the model flow is in a drag square zone. It holds through analyses that a resistance similarity is an important similarity condition for river model . However, a undistorted model with a larger scale is generally not in the drag square zone , theoretically , the needs for resistance similarity can't strictly met. Such being the case , accuracy of test results can be obtained through verification on condition that a model is similar to prototype, departure from water surface profile is in a limit required and distribution of flow velocity on cross-section coincides basically with each other.