CAJ | 학술논문

本文使用PIV术对低高速侧速比为0.25、0.33和0.5时竖直通道内的混合层流动进行实验研究,基于速度差和通道水力直径的雷诺数范围15840～132000.研究发现混合层内湍流参数的分布不仅和雷诺数有关,还和速比有关.混合层内同一横截面上平均雷诺应力的最大值随雷诺数的增大而增大,而在同一横截面上相同雷诺数时雷诺应力的最大值则随速比的增大而减小.在同一横截面上平均涡量随雷诺数的增大而增大,雷诺数相同时平均涡量的最大值随速比的增大而增大.无量纲平均涡量的最大值随混合层的发展按指数规律衰减,速比越大衰减速度越快.
본문사용PIV술대저고속측속비위0.25、0.33화0.5시수직통도내적혼합층류동진행실험연구,기우속도차화통도수력직경적뢰낙수범위15840～132000.연구발현혼합층내단류삼수적분포불부화뢰낙수유관,환화속비유관.혼합층내동일횡절면상평균뢰낙응력적최대치수뢰낙수적증대이증대,이재동일횡절면상상동뢰낙수시뢰낙응력적최대치칙수속비적증대이감소.재동일횡절면상평균와량수뢰낙수적증대이증대,뢰낙수상동시평균와량적최대치수속비적증대이증대.무량강평균와량적최대치수혼합층적발전안지수규률쇠감,속비월대쇠감속도월쾌.
In present paper,the effect of velocity ratio on plane mixing layer is experimentally investigated with Particle Image Velocimetry(PIV).The velocity ratio between low-and high-speed side are 0.25.0.33 and 0.50.respectively.The Reynolds number based on the velocity difierence of two streams and hydraulic diameter of the channel ranges from 15840～132000.The results indicate that the maximum mean Reynolds stress on the same cross section increases with Reynolds number increasing but decreases with velocity ratio increasing at the equal Reynolds number.The mean vorticity increases with Reynolds number increasing on the same cross-section and increases with the velocity ratio increasing at the equal Reynolds number.The maximum non-dimensional mean vorticity decreases according to an exponential law along the stream-wise direction,and the decreasing speed of maximum mean vorticity increases with the velocity ratio increasing.