Effect of duct geometry on shock wave discharge

This paper describes computational work to understand the unsteady flow-field of a shock wave discharging froman exit of a duct and impinging upon a flat plate.A flat plate is located downstream, and normal to the axis of theduct.The distance between the exit of the duct and fiat plate is changed.In the present study,two different ductgeometries(i.e.,square and cross section)are simulated to investigate the effect of duct geometry on theun-steady flows of a shock wave.In computation,the total variation diminishing(TVD)scheme is employed tosolve three-dimensional,unsteady,compressible,Euler equations.Computations are performed over the range ofshock Mach number from 1.05 to 1.75.Computational results can predict the three-dimensional dynamic behav-iour of the shock wave impinging upon the flat plate.The results obtained show that the pressure increase gener-ated on the plate by the shock impingement depends on the duct geometry and the distance between the duct exitand plate,as well as the shock Mach number.It is also found that for the duct with cross-section,the unsteadyloads acting on the flat plate are less,compared with the square duct.     

Study on Spatial Evolution of Producer Service in Hangzhou City

1. Recent development in the study on producer serviceThe producer service refers to the service provided for production and business activities, instead of for individual consumers. As the mid-term input service, it     

钻井液用降粘降滤失剂MGBM-1的研制

以木质素磺酸盐为主要原料，通过甲醛缩合反应，烯类单体接枝共聚合反应，金属离子络合反应及磺化剂磺化反应等一系列化学改性处理工艺，合成了兼具降粘，降滤失作用的新型钻井液处理剂MGBM－1，室内性能评价结果表明，MGBM－1具有明显的降粘和降滤失效果，在其加量为0．5％时，表面粘度下降50％，滤失量下降51％，动切力下降80％，静切力下降幅度更大；抗盐能力优于FCLS，具有较好的热稳定性，岩心滚动回收率高于FCLS。并从分子作用基团角度对MGBM－1的作用机理进行了探讨。     

Study on Spatial Development of Yangtze River Delta Region Since 1980s

The Yangtze River Delta(referring to the YRD hereafter) region has been developed very early,being the birthplace of Wu-Yue Culture and national industry of China, and has become the important core area of economic society of China for a long period. During the latest 20 years after the reform and opening up and along with the rapid