消力池导墙点面脉动壁压特性研究

Experimental study of characteristics of wall pressure fluctuation acting on apron of stilling basin

以高坝洲水电站消力池导墙上点、面脉动壁压的同步试验资料为基础,通过随机分析对点、面脉动壁压强度与谱密度函数的变化进行了探讨,并用VITA法对点面脉动壁压的相干模式进行了识别,得到如下成果:作用于消力池导墙上的面脉动壁压强度最大值与上、下游水位之差有关,而点脉动壁压强度与其基本无关;在谱密度函数中,点脉动壁压存在f-1和f-7/3的频谱段,而面脉动壁压的f-7/3频谱段并不明显,且其优势频率略小于点脉动壁压的优势频率;所研究的水流脉动壁压与平顺水流情况下的脉动壁压时间相干模式颇为相似,且点脉动壁压的相干时间比面脉动壁压小.

The intensity and spectrum function of wall pressure fluctuation acting on some single points as well as on the whole apron were investigated by stochastic analysis based on the data got from model test of Gaobazhou Hydropower Station,and the coherent mode of wall pressure fluctuation was also identified by VITA method.The results are as follows：The maximum intensity of wall pressure fluctuation acting on the whole apron is connected with the difference level of the upstream and downstream while the intensity of wall pressure fluctuation acting on some single points has no connections with it.What＇s more,the dominant frequency of the latter is slightly less than the former one.The coherent mode of the time of wall pressure fluctuation is similar to the smooth flow; and the coherent time of wall pressure fluctuation acting on some single point is less than that on the whole apron.