多元线性回归模型对于空气质量的校准应用研究

自改革开放以来,随着国家经济的快速发展,生态环境遭到一定程度的破坏,空气质量问题也日益严重。本研究聚焦于国控点和自建点大气监测数据进行可视化探索性研究分析,首先以国控点数据为参照对象,以自然因素为变量进行对比分析,研究自然因素对自建点数据的影响。然后分别采用一元线性回归和多元线性回归两种方法对现有的空气质量检测仪存在的问题进行分析,确定各自然因素与空气质量数据的影响程度。最后通过一元和多元线性回归模型模拟分析,校准自建点数据。

Characteristics and mechanism investigation on drag reduction of oblique riblets

This work primarily focuses on the drag reduction characteristics and mechanism investigation of oblique riblets. First, a calculation model of the oblique riblets surface is established, and Reynolds stress model(RSM) turbulence model is used for numerical simulation of the oblique riblets flow field. Subsequently, the influence of inclination angle between flow direction and arrangement direction of riblets on friction resistance and drag reduction rate is further analyzed. Through the investigation of the distribution of shear stress, pressure stress and velocity in oblique riblets boundary layer, the oblique riblets drag reduction mechanism is finally revealed. Results show that, with increase of velocity and inclination angle, the pressure resistance increases obviously, along with the decreasing of the viscous resistance distinctly. The maximum drag reduction rate of the oblique riblets is 7.33%. Moreover, when the inclination angle increases, the wall shear stress reduces on oblique riblets surface; while differential pressure increases at both sides of oblique riblets tips. In addition, when inclination angle is small, the secondary vortex at oblique riblets tips will disappear soon. New vortices will be formed inside the oblique riblets and cause the decrease of viscosity resistance. Thus, oblique riblets show a better drag reduction effect and have an effective control on boundary layer.

仿虾蛄沟槽蜗壳对旋流泵压力脉动的影响（英文）

为了改善旋流泵的压力脉动,基于仿生学原理,以虾蛄为生物原型,抽取虾蛄腹节处沟槽仿生工程化模型,建立不同沟槽数的仿虾蛄沟槽蜗壳的旋流泵模型。采用数值模拟方法,对不同沟槽数的旋流泵模型进行计算,研究蜗壳沟槽对旋流泵压力脉动的影响。结果表明:仿生沟槽结构对旋流泵外特性造成的影响很小,但仿生沟槽结构可以通过改善旋流泵隔舌部位流体的流线,抑制漩涡的生成,有效地抑制靠近隔舌区域及旋流泵出口处的叶频压力脉动,降低旋流泵整体的压力脉动,提高旋流泵运行稳定性。