The near-field characteristics of circular jets at low Reynolds numbers
The near-field characteristics of circular jets at low Reynolds numbers
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DOI：
10.1016/0093-6413(96)00028-6
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发表时间：
1996-05-01
影响因子：
2.4
通讯作者：
Chakroun, W
中科院分区：
文献类型：
--
作者：
AbdelRahman, AA;AlFahed, SF;Chakroun, W
对雷诺数对圆形湍流空气射流近场区的影响进行了实验研究。测量采用双分量激光多普勒风速仪，包括平均速度，湍流强度，偏斜因子，平坦因子和功率谱。测量了10喷嘴出口直径在下游方向不同的出口雷诺数在1400至20000的范围内。雷诺数被发现有强烈的影响，在近场区域的射流现在的行为;中心线速度衰减更快（衰减常数= 6.11为Re = 19400，= 1.35为Re = 1430）和潜在的核心变得更短，随着雷诺数的减少。剖面测量的偏斜度和平坦度的因素表明，现在的射流变得更加间歇性的雷诺数减少。流向脉动速度的功率谱测量反映了高雷诺数射流的高能量含量。随着雷诺数的增加，在较高的频率处有更大的能量。
An experimental study has been undertaken to investigate the effect of Reynolds number on the near-field region of circular turbulent air jets. Measurements were made using a two-component Laser Doppler Anemometer, and included mean velocity,turbulence intensity, skewness factor, flatness factors and power spectrum. Measurements were taken up to 10 nozzle exit diameter in the downstream direction for different exit Reynolds numbers in the range of 1400 to 20000. The Reynolds number was found to have a strong effect on the jet now behavior in the near-field region; the centerline velocity decays faster (decay constant = 6.11 for Re = 19400, = 1.35 for Re = 1430) and the potential core gets shorter with decreasing Reynolds number. Profile measurements of the skewness and flatness factors indicate that the jet now becomes more intermittent with decreasing Reynolds number. Power spectrum measurements of the streamwise fluctuating velocities reflects the high energy content of the high Reynolds number jet. It also reveals that there is greater energy at the higher frequencies with increasing Reynolds number.