绕旋转圆柱流动涡尾流结构和临界状态特性

基于区域分解, 有限差分法和涡法杂交的数值方法, 结合高阶隐式差分格式, 和以修正的不完全LU分解为预处理器的共轭梯度法作求解器. 研究了雷诺数Re＝1000, 旋转速度比α∈(0.5,3.25)范围内, 绕旋转圆柱从突然起动到充分发展, 长时间内尾流旋涡结构和阻力, 升力系数的变化规律. 计算所得流动图案与实验流场显示符合很好, 数值试验证实了临界状态的存在

“引汉济渭”受水区居民支付意愿研究

为对\"引汉济渭\"引水工程的生态补偿政策、水权配置和定价提供参考依据,应用条件价值评估法（CVM）的多边界离散选择（MBDC）模型进行问卷调研,基于566个有效样本,运用Welsh-Poe模型和Wang-He两步法模型,对\"引汉济渭\"受水区西安市居民的支付意愿（WTP）及其影响因素进行分析。研究发现:西安市居民总支付意愿为17.14元/户*月-1,肯定愿意、可能愿意、不确定的支付意愿分别为8.36、14.39和20.82元/户*月-1;受访者的各项家庭异质性因素均会对受水区支付意愿产生显著影响;西安市居民对于\"引汉济渭\"引水工程的支付意愿主要源于水质改善需求。国家社会科学基金重大项目(12&ZD072);;陕西省软科学研究计划重点项目(2015KRZ006

Antiviral Effect of Glycyrrhizin on Porcine Respiratory Coronavirus (PRCV)

利用ST细胞研究了甘草酸对猪呼吸道冠状病毒(PRCV)体外复制过程中的抑制作用。通过RT-PCR和Western blot检测发现甘草酸能有效抑制PRCV的体外复制而对ST细胞不引起明显细胞毒作用。抑制效果与甘草酸的剂量成正比关系。PRCV病毒核衣壳蛋白的表达无论在mRNA水平还是在蛋白质水平均随着甘草酸添加量的增加而降低,提示甘草酸是一种有效的抗PRCV药物。The inhibitory effect of glycyrrhizin (GL) on porcine respiratory coronavirus (PRCV) replication was investigated in vitro in ST cells using RT-PCR and Western blot techniques.GL effectively suppressed PRCV replication without causing apparent cell cytotoxicity in ST cells.The inhibitory effect of GL on PRCV was in a dose-dependent manner.The expression levels of both mRNA and protein of the PRCV nucleocapsid protein in ST cells were impeded by the increasing addition of GL,suggesting it is a potential effective antiviral component against PRCV in vitro.This project was supported by a grant from the Bureauof Science and Technology of Fujian Province (2003N083);; agrant from the Bureau of Science and Technology of Xiamen City(3502Z20031054

熔锥光纤与球微腔耦合系统的理论模拟

利用H. J. Shaw提出的单模光纤定向耦合器的分析方法并结合微球腔的特性,对熔锥光纤与球微腔系统的耦合特性进行了理论分析和数值模拟。研究表明,由于原本简并的球腔模式受腔体偏心率的影响而解除,系统吸收峰间距减小,Q值( 106 ~107 )比将腔体视为理想球时提高了三个数量级。这与已报道的实验结果相吻合

MILU-CG方法和绕旋转圆柱流动的数值研究

本文采用以修正的不完全ＬＵ分解作预处理器的共轭梯度法（ＭＩＬＵ＿ＣＧ），结合高阶隐式差分格式，改进了作者（１９９２）提出的基于区域分解、有限差分法与涡法杂交的数值方法（ＨＤＶ）·系统地研究了雷诺数Ｒｅ＝１０００，２００，旋转速度比α∈（０５，３２５）范围内，绕旋转圆柱从突然起动到充分发展，长时间内尾流旋涡结构和阻力、升力系数的变化规律·计算所得流线与实验流场显示相比，完全吻合·首次揭示了临界状态时的旋涡结构特性，并指出最佳升阻比就在该状态附近得

圆柱振荡绕流中涡旋运动模式(pattern)的数值模拟

提出并发展的一种基于区域分解思想,综合了解 N—S方程的有限差分法及涡法各自优点的新数值方法,计算了各种 Keulegan-Carpenter 数下(Kc=2～24)振荡流绕圆柱的流动。系统地研究了振荡流中涡旋运动模式随 Kc 数变化的规律,模拟了不对称区、单对涡区(或模向区)、双对涡区(或对角区)和三对涡区四种不同的涡旋运动模式。将计算所得的阻力系数 C_D、惯性系数 C_M与国外近期发表的计算结果进行了比较

钝体分离旋涡流动的区域分解、杂交数值模拟——Ⅰ.理论方法及其应用

为克服涡旋法不能精确预计物体附近小尺度流动结构的理论缺陷,减少高Reynolds数流动N-S方程差分解的困难,本文提出一种区域分解、杂交耦合N-S方程有限差分解及涡旋法的新的数值模型和理论方法.将流场分解为内外两区,在靠近物体表面、范围为O(R)的内区进行N-S方程有限差分解,外区作Lagrange-Euler涡旋法解,建立了分区流动的联结、耦合条件,给出了杂交耦合求解的数值计算方法.用本方法作了Re=10~2,10~3的圆柱绕流计算,考察了区域交界面位置变化时解的稳定性.与全场N-S方程解及实验结果的比较表明本文方法能精确预计流动分离及近场流动的详细结构,并可有效地计算流动的总体特性,且比全场N-S方程解显著节省机时和计算量

Domain decomposition hybrid method for numerical simulation of bluff body flows:theoretical model and application

The discrete vortex method is not capable of precisely predicting the bluff body flow separation and the fine structure of flow field in the vicinity of the body surface. In order to make a theoretical improvement over the method and to reduce the difficulty in finite-difference solution of N-S equations at high Reynolds number, in the present paper, we suggest a new numerical simulation model and a theoretical method for domain decomposition hybrid combination of finite-difference method and vortex method. Specifically, the full flow. field is decomposed into two domains. In the region of O(R) near the body surface (R is the characteristic dimension of body), we use the finite-difference method to solve the N-S equations and in the exterior domain, we take the Lagrange-Euler vortex method. The connection and coupling conditions for flow in the two domains are established. The specific numerical scheme of this theoretical model is given. As a preliminary application, some numerical simulations for flows at Re=100 and Re-1000 about a circular cylinder are made, and compared with the finite-difference solution of N-S equations for full flow field and experimental results, and the stability of the solution against the change of the interface between the two domains is examined. The results show that the method of the present paper has the advantage of finite-difference solution for N-S equations in precisely predicting the fine structure of flow field, as well as the advantage of vortex method in efficiently computing the global characteristics of the separated flow. It saves computer time and reduces the amount of computation, as compared with pure N-S equation solution. The present method can be used for numerical simulation of bluff body flow at high Reynolds number and would exhibit even greater merit in that case