Direct numerical simulations have been applied to simulate flows with polymer additives. FENE-P (finite-extensible-nonlinear-elastic-Peterlin) dumbbell model solving for the conformation tensor is adopted to investigate the influence of the polymer on the flowfield. Boundary treatments of the conformation tensor on the flowfield are examined first, where boundary condition based on the linear extrapolation scheme provides more accurate results with second-order accurate error norms. Further simulations of the turbulent channel flow at different Weissenberg numbers are also conducted to investigate the influence on drag reduction. Drag reduction increases in tandem with the increase of Weissenberg number and the increase saturates at Weτ~200, where the drag reduction is close to the maximum drag reduction (MDR) limit. At the regime of y+ > 5, the viscous layer thickens with the increase of the Weissenberg number showing a departure from the traditional log-law profile, and the velocity profiles approach the MDR line at high Weissenberg number. The Reynolds stress decreases in tandem with the increase of Weτ, whereas the levels of laminar stress and polymer stress act adversely. However, as the Weissenberg number increases, the proportion of the laminar stress in the total stress increases, and this contributes to the drag reduction of the polymer flow.

直接数值模拟已应用于模拟含聚合物添加剂的流动。采用FENE-P（有限可扩展非线性弹性彼得林）哑铃模型求解构象张量，以研究聚合物对流场的影响。首先检查流场上构造张量的边界处理，其中基于线性外推方案的边界条件以二阶精确误差范数提供了更准确的结果。还对不同Weissenberg数下的湍流通道流动进行了进一步的模拟，以研究其对减阻的影响。在串联阻力减小与增加的魏森伯格数量的增加而增加，在饱和我们τ〜200，其中减阻接近最大减阻（MDR）限制。在y + > 5的状态下，粘性层随着魏森伯格数的增加而增厚，这表明它偏离了传统的对数律分布，速度分布在魏森伯格数高时接近MDR线。雷诺应力与增加的串联减小我们τ，而层应力和不利的聚合物应力行为的水平。然而，随着魏森伯格数的增加，层流应力在总应力中的比例增加，这有助于降低聚合物流的阻力。