水流脉动压力过程的正交展开  

Orthogonal expansion of processes for fluctuating pressure of water flow

作　　者：周宜红[1,2] 叶恩立 

机构地区：[1]武汉大学水资源与水电工程科学国家重点实验室,湖北武汉430072 [2]三峡大学水利与环境学院,湖北宜昌443002 [3]中国水电顾问集团昆明勘测设计研究院,云南昆明650051

出　　处：《武汉大学学报（工学版）》2014年第3期332-335,共4页Engineering Journal of Wuhan University

基　　金：国家"十一五"科技支撑计划项目(编号:2008BAB29B02-2-2)

摘　　要：应用了一类基于标准正交基的随机过程展开方法,通过预先指定标准正交基的形式,结合水流脉动压力过程的自相关函数,将水流脉动压力随机过程在标准正交三角函数基上进行正交展开,为分析由脉动水压力所引起的结构随机动力响应建立了一个激励产生(输入)数学模型.利用该模型,水流脉动压力随机过程的主要概率特性可以通过少量的独立随机变量来进行描述,进而为从概率密度演化的角度对结构在脉动水压激励下的响应及可靠度分析奠定了基础.通过实例,针对给定的相关函数应用了该模型,从样本集合功率谱以及样本均方差等二阶数值统计的意义上验证了该模型的有效性,并讨论了模拟时距和展开项数对模拟效率及精度的影响.Combining with its auto-correlation function, the stochastic process of water-flow＇s fluctuating pressure is decomposed on the trigonometric function bases by employing an expansion method based on normalized orthogonal bases which is prescribed; and thus an incentive model for the random dynamic response analysis of structures vibrated by water-flow＇s fluctuating pressure, is established. By using the model, main probabilistic characters of the stochastic process are captured with only a few random varia- bles; and therefore the foundation for further random response and reliability analysis is built. From the point of probability density evolution. The validity of the model is tested from the aspect of second order statistics such as sampling ensemble power spectrum and sample mean square error by using it in an instance; the effects of simulation duration and expansion numbers needed on the simulation＇s efficiency and accuracy are also discussed.

关 键 词：水流脉动压力 随机过程 正交展开 标准正交基 自相关函数 

分 类 号：TV131.33[水利工程—水力学及河流动力学]