摘要
泥沙河工模型采用轻质模型沙时,往往存在水流运动时间比尺与河床冲淤时间比尺不一致的矛盾.目前的做法多为偏离前者而遵循后者,即采取时间比尺的变态,以尽可能保持河床冲淤的相似性,并缩短试验历时.但时间变态结果.对长距离河段的非恒定水沙过程的模拟,将在一定程度上导致沿程流速、水位、狭沙能力和河床冲淤量的偏离.本文首先对时间变态问题及其影响进行了概略性分析,进而通过水流连续方程和运动方程的数值求解,对时间变态所引起的诸水力因素和河床冲淤沿程偏离的性质及偏离的程度进行了定性和定量的分析计算,最后研究了校正这类偏差的途径和方法.
When light weight material is used as model sand in a physical model with unsteady flow and movable river bed, the time scale of deformation of channel bed λt2 usually differs from the time scale of water flowλt1 Generally,λt2, is adopted as the time scale of the model test and this brings in a time distortion consequently. This time scale distortion results in some dissimilarities of flow velocity, water stage, sediment transport capacity and the amount of deposition or erosion of the model test. The longer, the modeling stretch is, the greater, the deviation. By using a numerically solution of continuity equation and flow motion equation, the deviations of results of model test caused by time scale distortion were qualitatively and quantitatively analyzed in this paper. The measures to correct this kind of dissimilarities were also investigated and verified in a practical river model.
出处
《泥沙研究》
CSCD
北大核心
1989年第2期12-24,共13页
Journal of Sediment Research
