【摘要】 本文在纯水混合层流动实验的基础上,使用PIV对添加高分子聚合物形成的粘弹性混合层流动进行实验研究,聚合物浓度为200mg/kg。混合层高低侧速比为4:1,速度差0.25～1.25 m/s。研究发现在纯水及粘弹性流体中均存在有明显的涡结构,添加聚合物后流场中的涡结构尺度变大,涡核也较清晰。雷诺应力则随着速度差的增大而减小,涡量随速度差的增大而增大。同纯水混合层比较,添加聚合物后的雷诺应力与涡量的峰值区域都比纯水的更宽,作用范围更大。更多还原

【Abstract】 Turbulent mixing layer flow with 200 mg/kg polymer additives was measured by PIV and compared with pure water cause.The velocity ratio between high and low speed is 4:1 and the velocity difference ranges from 0.25 m/s to 1.25 m/s.It is showed that large vortex structures exist in flow field with/without polymer addictives,but the coherent structure is much clearer and the large eddy will roll up earlier when polymer is added.Similar with pure water case,the Reynolds stress is decreasing and the vorticity is increasing with increasing the velocity difference.However,the width and range of Reynolds shear stress and vortieity are wider and larger.更多还原