急流脉动压力相似律及其特性研究

发布时间：2018-03-09 05:06

本文选题：急流　切入点：模型试验　出处：《天津大学》2014年硕士论文　论文类型：学位论文

【摘要】：目前，高速水流压力脉动对于水工建筑物的影响是工程界普遍关心的问题，，但是水流脉动的内在实质尚未从理论上完全搞清楚，数值计算缺乏理论支撑，而原型观测受到现场条件限制，故人们更多地是利用水工模型试验研究水流脉动压力。急流脉动压力相似律问题尚未解决，模型中所获成果就不能“完整”地应用到实际工程中，即脉动压力幅值可按重力相似准则换算到原型，而频率就无法换算，给结构的稳定性分析带来障碍。本文主要以急流脉动压力为研究对象，利用三个不同模型研究陡槽上急流脉动压力满足的相似准则。在自主设计陡槽模型上研究急流脉动压力满足的相似准则，找到急流脉动压力模型和原型转换满足的规律。在两个工程实体缩尺模型上对陡槽上急流和水跃区水流的脉动压力进行对比研究。本文主要做了以下内容：（1）以自主设计模型为研究对象，进行系列模型试验，计算了K值及其概率分布，比较不同比尺K值的分布情况。计算脉动压强系数β，得出脉动压力幅值满足的相似准则。分析不同比尺下脉动压力概率分布和特征值CS、CE的分布情况。对不同比尺下脉动压力时空相关特性进行研究。利用傅里叶变换，分析不同比尺水流脉动压力功率谱，得到水流脉动压力频率相似满足的规律。（2）以某实际工程缩尺模型为研究对象，进行系列比尺试验。与自主设计模型中对脉动压力的分析对象相同，对该模型系列比尺下的脉动压力进行研究，得到模型和原型上急流脉动压力的幅值和频率满足的相似准则。（3）研究陡槽段和消力池段内的水流，即对陡槽上急流脉动与水跃区脉动进行对比研究。研究内容包括脉动压力均方根、脉动压力的K值、脉动压力概率分布及特征值CS和CE、脉动压力频率特征值及相关性等。
[Abstract]:At present, the influence of high speed flow pressure pulsation on hydraulic structures is of general concern to the engineering community. However, the intrinsic essence of water flow pulsation has not been fully understood in theory, and the numerical calculation lacks theoretical support. But the prototype observation is restricted by the field conditions, so the hydraulic model test is used to study the flow pulsation pressure, and the problem of the similarity law of the jet pulsation pressure has not been solved. The results obtained in the model can not be "completely" applied to practical engineering, that is, the amplitude of pulsating pressure can be converted to prototype according to the criterion of gravity similarity, but the frequency can not be converted, which brings obstacles to the stability analysis of structures. In this paper, three different models are used to study the similarity criterion of the jet pulsation pressure on the channel, and the similarity criterion of the jet pulsation pressure satisfaction is studied on the self-designed trough model. To find out the law of the jet pulsating pressure model and prototype conversion, and to compare the pulsating pressure between the jet flow and the hydraulic jump flow on two engineering entity scale models. The main contents of this paper are as follows:. 1) taking the autonomous design model as the research object, a series of model tests are carried out, and the K value and its probability distribution are calculated. The distribution of K value of different scale is compared, the coefficient of pulsating pressure 尾 is calculated, and the similarity criterion of amplitude value of pulsating pressure is obtained. The probability distribution of pulsating pressure and the distribution of characteristic value CSN CE under different scale are analyzed. The temporal and spatial correlation of pulsating pressure is studied. By analyzing the power spectrum of flow pulsation pressure with different scales, the law of the similarity of flow pulsation pressure frequency is obtained. Taking the scale model of a practical engineering as the research object, a series of scale scale tests are carried out. The pulsating pressure under the scale of the model series is studied, which is the same as the analysis object of the pulsating pressure in the autonomous design model. The similarity criterion of amplitude and frequency of jet pulsation pressure on model and prototype is obtained. 3) to study the flow of water in the chute and the stilling pool, that is, to compare the pulsation of the jet current with the pulsation in the hydraulic jump region, including the root mean square of the pulsating pressure, the K value of the pulsating pressure, Probability distribution and eigenvalue of pulsating pressure CS and CE. characteristic value and correlation of frequency of pulsating pressure.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV131.3

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