1. Experimental and numerical studies of 3-D transitions & 2. Characteristics of some highly curvilinear flows

1. 3-D 转变的实验和数值研究

• 批准号: 7608-2013
• 负责人: Ramamurthy, Amruthur
• 金额: $ 2.04万
• 依托单位: Concordia University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=636094
• 关键词: 1.; Experimental; numerical; studies; transitions

Research proposal: 1. Channel transition flows 2. Highly curvilinear flows 1. The network of open channels supplying water to various end users from a reservoir can have a closed conduit or a rectangular concrete open channel attached to the reservoir to feed a larger trapezoidal earth channel. For efficient operation, the flow passes through a short transition. Reducing energy loss and secondary flow intensity are the main goals. Channel transitions should be shaped to limit energy losses by careful design that prevents flow separation. For instance, a warped transition linking a rectangular channel with a trapezoidal channel is a case in point. Reduced energy losses attain larger irrigation command areas. Reduced secondary flow intensity in downstream channels reduces channel erosion. The study investigates the characteristics of different transitions including the warped, wedged and cylindrical transitions. Transitions will be studied, after installing auxiliary devices (vanes & humps) to augment energy conservation and reduce secondary flow intensity. LDV (Laser Doppler velocimetry) and PIV (Particle Image Velocimetry) data will yield the mean and fluctuating velocity components to assess the energy conservation efficiency in transitions and reduction of secondary flow intensity in the downstream channels. Reynolds stress transport (RST) based CFD models will be developed to get the turbulent stresses. 2. In highly curvilinear flows, boundary layer approximations that permit one to assume that the stream wise velocity is dominant and that the transverse pressure gradient is negligible are not valid. Such flows occur in hydrocyclones, siphons and counter wall jets. To get a description of these flows, one seeks solutions that yield the details of turbulence behavior in terms of various scales, stresses and eddy characteristics. Both experimental studies and numerical modeling methods will be used.Siphons permit efficient ways of conserving stored water for end users. Improved hydrocyclones can segregate ingredients better. Efficient counter jets promote enhanced dilution of pollutants.

研究建议：1.通道转换流2.高曲线流1.从水库向各种终端用户供水的明渠网络可以具有附接到水库的封闭管道或矩形混凝土明渠，以向更大的梯形土渠供水。为了有效操作，流动通过短过渡。降低能量损失和二次流强度是主要目标。通道过渡段的形状应通过精心设计来限制能量损失，以防止流动分离。例如，连接矩形通道和梯形通道的扭曲过渡就是一个很好的例子。减少能量损失，扩大灌溉面积。下游渠道中二次流强度的降低减少了渠道侵蚀。研究了不同的过渡，包括翘曲，楔形和圆柱形过渡的特性。在安装辅助装置（叶片和驼峰）后，将研究过渡，以增加节能和降低二次流强度。LDV（激光多普勒测速仪）和PIV（粒子图像测速仪）数据将产生平均和脉动速度分量，以评估过渡中的能量守恒效率和下游通道中二次流强度的降低。将开发基于雷诺应力输运（CFD）的模型来获得湍流应力。2.在高度曲线流中，允许假定流向速度占主导地位而横向压力梯度可忽略的边界层近似是无效的。这种流动发生在水力旋流器、虹吸管和反向壁射流中。为了得到这些流动的描述，人们寻求根据各种尺度、应力和涡流特性产生湍流行为细节的解决方案。将采用实验研究和数值模拟方法。虹吸管允许为最终用户保存储存水的有效方法。改进的水力旋流器可以更好地分离成分。有效的反向射流促进污染物的增强稀释。