方形截面弯管中的Oldroyd-B流体流动

Flow of Oldroyd-B fluid in square duct

为了优化工业中非牛顿流体的流动,应用Galerkin方法来研究Oldroyd-B流体在方形截面管道中的充分发展流动.结果包括了Weissenberg数和Reynolds数对于粘弹流体流动的二次流、轴向速度以及法向应力差的影响.计算结果表明,由于上随体导数项的存在,Weissenberg数的增大会使得主流速度变小,而对二次流的影响不大.弹性力的作用不仅使得第一法向应力差的绝对值变大,而且会在外壁产生出一个负值区域.Weissenberg数的增大同样会使得第二法向应力差变大,并使其分布更为均匀.

A fully developed Oldr0yd-B fluid flow through a square duct was studied by Galerkin method in order to optimize the non-Newtonian fluid flow in applications. Results include secondary flow, axial velocity and normal stress difference, which are affected by the Weissenberg number and Reynolds number. The decreasing Weissenberg number decreases the main flow but has little effect on the secondary flow due to the existence of upper-convected derivative. The elastic force enlarges the absolute value of the first normal stress difference and creates a negative value area around the outer wall. The increasing Weissenberg number increases the second normal stress difference as well and equalizes its distribution in the cross-section.