摘要
用雷诺应力封闭模式(RSM)和κ-ε模式对底部放置了对称翼型的完全发展的非对称槽道流动进行了数值模拟研究。工程实际中有压力梯度变化的流动是较常见的,这些压力梯度会导致较强的湍流结构的变化,从而影响湍流的扩散和传输过程。用数值计算方法从压力梯度对湍流逆输运现象的影响角度展开研究,以期了解并揭示湍流道输运现象的物理机理。由计算结果可以看出,RSM模式能够较κ-ε模式更好地反映逆梯度输运(CGT)现象;逆梯度输运现象的出现比湍动能负产生率更为普遍;压力梯度的变化对湍动能负产生率区域和CGT区域的影响是有规律的,顺压梯度时,湍动能负产生率区域逐渐缩小,至压力梯度为零时消失,此时CGT区域从无到有,呈先增大后缩小的趋势;逆压梯度时,湍动能负产生率区域不复存在,此时CGT区域从有到无,也是呈先增大后缩小的趋势,并最终消失;CGT区域内雷诺应力与平均速度梯度呈非线性关系。
By using Reynolds Stress Closure Model (RSM) and k-ε Model,the turbulent field of wing flow is numerically simulated.In most practical situations,flows with changing pressure gradient are familiar,these pressure gradients may induce strong modifications of turbulent structure,accordingly,affect the diffusion and transportation process of turbulence.The effects of pressure gradient on counter-gradient transport phenomena are studied.The computational results show that RSM model can describe the CGT phenomena while k-ε model cannot.Negative turbulent energy production appears in the result of RSM,but it behaves differently with CGT: it gradually shrinks until the position of the wing central part is reached,where it vanishes; while the CGT region exists all along.This fact shows that CGT phenomena is more general than negative turbulent energy production.The pressure gradient takes an important effect on the region of negative turbulent energy production and counter-gradient transport.In the CGT region,the relation between turbulent Reynolds stress and mean velocity gradient is nonlinear.
出处
《力学学报》
EI
CSCD
北大核心
2004年第2期163-170,共8页
Chinese Journal of Theoretical and Applied Mechanics
基金
国家自然科学基金(19872043
10272071)~~
