水力学模型试验是解决高速水力学问题的有效途径，其中重力相似准则是普遍采用的模型试验相似准则，然而对于明渠自掺气水流，根据重力相似准则得到的模型掺气浓度与原型工程存在明显的差异，自掺气模型试验掺气浓度比尺效应细观成因不明确，目前无法根据一定的换算关系引申到原型工程。本项目通过系列模型试验，采用针式掺气仪和高速摄像机，对明渠高速自掺气水流不同流速、断面尺寸、壁面粗糙程度条件下自掺气宏观掺气浓度和细观气泡特性进行详细测量，研究模型比尺对自掺气宏观和细观特性的影响规律，通过对比自掺气水流气泡特性的差异，揭示模型试验掺气浓度比尺效应的细观成因，研究不同水流弗劳德数、雷诺数、韦伯数、壁面糙率对掺气浓度和气泡特性相关关系的影响规律，探索确定自掺气水流掺气浓度比尺效应无量纲影响因子，获得适用于自掺气水流不同比尺掺气浓度引申计算方法，为准确预测自掺气对工程设计的影响提供可靠的科学依据。

Physical hydraulic modelling is an effective method and the criterion of gravitational force similarity is most often applied in open channel hydraulics. However, the self-aeration characteristics of high-speed open channel flows are statistically incorrectly scaled in a Froude similarity model between the model and prototype flows. Scale effects for self-aeration arise in scale model, and the limiting criteria and correction method for prototype application are still unclear. Based on a series of systematically experimental study, self-aeration properties are measured in high-speed open channel flows under different flow velocity, cross-section size and wall roughness conditions. The effect of scale ratio on air concentration, diffusion region and air bubble properties is investigated. The mechanism of air concentration scale effect is analyzed based on the deviations of microscopic air bubble property in open channel flows. The influences of Froude number, Reynolds number, Weber number and roughness coefficient on scale effect of self-aeration are studied, and the new general influencing factor is studied to quantify the scale effect of air concentration in open channel flows. The calculation relationship of air concentration between scaled model and prototype will be explored for providing precise influence of self-aeration and reliable guidance in hydraulic engineering design.