标题： 撞击平面未膨胀射流的壁面射流相似性 显示英文标题

标题： Wall Jet Similarity of Impinging Planar Underexpanded Jets

摘要： 速度分布和壁面射流区域的壁面剪切应力值基于喷嘴参数（离距高度、射流水力直径和喷嘴压力比）进行参数化。 计算流体力学用于计算高度与直径比在15到30范围内的冲击射流的速度场，以及喷嘴压力比在1.2到3.0范围内的速度场。 壁面射流具有不完全自相似的分布，具有传统壁面射流的典型三层结构。 发现对于马赫数小于0.8的壁面射流，可压缩性的影响可以忽略不计。 壁面射流分析得到了幂律关系，其源依赖系数描述了最大速度、摩擦速度以及最大速度和半最大速度对应的壁面距离。 源依赖性使用共轭梯度法确定。 这些幂律关系可用于根据喷嘴参数映射壁面剪切应力。 显示英文摘要

摘要： Velocity profiles and wall shear stress values in the wall jet region of planar underexpanded impinging jets are parameterized based on nozzle parameters (stand-off height, jet hydraulic diameter, and nozzle pressure ratio). Computational fluid dynamics is used to calculate the velocity fields of impinging jets with height-to-diameter ratios in the range of 15 to 30 and nozzle pressure ratio in the range of 1.2 to 3.0. The wall jet has an incomplete self-similar profile with a typical triple-layer structure as in traditional wall jets. The effects of compressibility are found to be insignificant for wall jets with Ma<0.8. Wall jet analysis yielded power-law relationships with source dependent coefficients describing maximum velocity, friction velocity, and wall distances for maximum and half-maximum velocities. Source dependency is determined using the conjugate gradient method. These power-law relationships can be used for the mapping of wall shear stress as a function of nozzle parameters.