An Efficient High-Resolution Shock-Capturing Scheme for Multi-Dimensional Flows I. Hydrodynamics

Many problems at the forefront of theoretical astrophysics require a treatment of dynamical fluid behavior. We present an efficient high-resolution shock-capturing hydrodynamic scheme designed to study such phenomena. We have implemented a weighted, essentially non-oscillatory （WENO） scheme to fifth order accuracy in space, lILLE approximate Riemann solver is used for the flux computation at cell interface, which does not require spectral decomposition into characteristic waves and so is computationally friendly. For time integration we apply a third order total variation diminishing （TVD） Runge-Kutta scheme. Extensive testing and comparison with schemes that re.quire characteristic decomposition are carried out demonstrating the ability of our scheme to address challenging open questions in astrophysics.

化学驱中聚合物水动力学尺寸及最优匹配注入研究

为了明确化学驱中聚合物的注入性,针对聚合物(P)体系、碱-聚合物(AP)体系、表面活性剂-聚合物(SP)体系及碱-表面活性剂-聚合物(ASP)体系通过多组对比实验分析了各因素对聚合物水动力学直径Dh的影响,并进行了6种渗透率K岩心的P体系注入性实验以确定最优匹配注入界限。结果表明:P体系中,Dh随着聚合物相对分子质量Mr、浓度C的增加而增大。AP体系中,Dh随着碱浓度的增加而减小,且强碱作用效果比弱碱大;SP体系中,Dh随着表面活性剂浓度的增加先略微增大然后减小。ASP体系中,当表面活性剂含量相对聚合物较小时,碱和表面活性剂对Dh起相互制约作用;当表面活性剂含量较大时,碱和表面活性剂对Dh起协同作用。将聚合物溶液注入岩心时,需要遵循以下条件:当53×10-3≤K<91×10-3μm2时,注入的聚合物溶液应满足C<1 g·L-1、Mr<1×107;当91×10-3≤K<146×10-3μm2时,注入的聚合物溶液应满足C<2 g·L-1、Mr≤1×107;当146×10-3≤K<199×10-3μm2时,注入的聚合物溶液应满足C≤2 g·L-1、Mr≤1.5×107;而当199×10-3≤K<252×10-3μm2时,注入的聚合物溶液应满足C≤2.5 g·L-1、Mr≤2.7×107。