摘要
对无剪切湍流混合层中被动标量的扩散进行了直接数值模拟。结合烟粒子扩散风洞实验研究了不同Sc数对被动标量扩散的影响。DNS中被动标量的Sc数取为0.2和3。平均标量场基本上与Sc数无关,脉动标量方差随着Sc数的增加而增加,当Sc>1时,无量纲的质量通量与Sc数基本无关,而Sc=0.2时的质量通量与Sc>1的质量通量有较大的差别。
The diffusion of passive scalar in shearless turbulent mixing layer was computed by DNS (direct numerical simulation). The effect of Schmidt number on the turbulent diffusion of passive scalar was studied together with experimental data in wind tunnel with incense as passive scalar. Sc number equals 0.2 and 3 respectively in DNS. Comparing the results of different Sc numbers including the data of high Sc number in experiment, it is found that the mean scalar profile is almost independent of Sc number, and the variance of fluctuated scalar concentration increases with Sc number. It is also observed that non-dimensional mass flux is almost independent of Sc number when Sc number is greater than 1, while the non-dimensional mass flux of Sc=0.2 is different from that of Sc>1, because the molecular diffusion effect takes place when Sc number is very small.
出处
《工程力学》
EI
CSCD
北大核心
2004年第3期36-39,共4页
Engineering Mechanics
