平板层流边界层定常流动存在相似性解区域的分析

对于无限薄半有限长度的平板层流,布拉修斯(H.Blasius)等学者得到了全尺寸范围内的相似性解,并与尼古拉兹(J.Nikuradse)的试验数据十分相符.但对有限厚度平板,由于边界条件的变化和数学上的困难而未得到其相似性解.本文利用PHOENICS软件和MATLAB软件对无限薄平板和有限厚度平板的层流边界层定常流动过程进行了数值模拟计算,分析了边界层中速度分布存在相似性解的区域.计算和分析表明,对无限薄平板,数值模拟解与布拉修斯解完全吻合,而对有限厚度平板,仅在一定范围内存在相似性解.说明了利用PHOENICS软件对此类流动进行数值模拟计算的适用性和准确性.同时,也显示出采用计算流体力学软件解决流动问题的优越性.

Analysis of Region Having Similar Solutions of Velocity in Fixed-Flux Condition of Flat Laminal Borderland

To laminal borderland of nearly thickless, half_limited length flat, many scholars such as H.Blasius get similar solutions of whole borderland, which coherent to J.Nikuradse's experimental data, however, to limited_thickness flat, it's very difficult to get these solutions because of the changing boundary condition and difficulty in math. The paper uses softwares named PHOENICS and MATLAB to simulate and calculate the fixed_flux condition of flat laminal borderland, and analyses region having similar solution of velocity in borderland. The calculation and analysis indicate that those solutions cohere to H.Blasius's in nearly thickless flat,but there are only similar solutions in definite domain of limited_thick flat.All of those show that it's not only useful and exact but also predominant to use PHOENICS to simulate these flows.