Tests and Numerical Simulation of Aerodynamic Characteristics of Airfoils for General Aviation Applications

This paper was to validate the effects of airfoil thickness ratio on the characteristics of a family of airfoils. Research was carried out in different ways. First, tests were conducted in the wind tunnel. And numerical simulation was performed on the basis of tests. Results from calculation were consistent with tests, indicating that numerical method could help evaluate characteristics of airfoils. Then the results were confirmed by compared with empirical data. The study also showed that the determining factor of lift is not only the thickness ratio, but the angle of attack, the relative camber and the camber line. The thickness ratio appears to have little effect on lift coefficient at zero angle of attack, since the angle of zero lift is largely determined by the airfoil camber. According to the research, numerical simulation can be used to determine the aerodynamic characteristics of airfoils in different environment such as in the dusty or humid air.     

购买母牛不受孕能否要求返回购牛款

近年来．由于牛奶需求量的增加，养殖奶牛成了人们致富的义一途径。而由于奶牛买卖引发的纠纷也时有发生。     

喷射混凝土加固墙体施工技术

根据校安加固工程施工情况,从喷射混凝土施工工艺流程、原材料及配合比、喷射作业以及喷射混凝土的强度检验等工序介绍了喷射混凝土在砖混结构加固工程中对砖墙加固的施工技术.     

秋水仙素诱导蒙古黄芪多倍体的研究

以黄芪种子和带子叶的上胚为处理对象,用在培养基里添加不同浓度秋水仙素的方法,研究了秋水仙素不同浓度、不同处理时间对黄芪多倍体诱导的影响.结果表明,两种处理对象的诱导效果受秋水仙素浓度和处理时间两方面的影响.以成熟种子为处理对象,各种秋水仙素浓度和处理时间组合均可诱导出多倍体植株,但以秋水仙素浓度100mg/L,处理时间14d的组合加倍率最高,达13.3%;以带子叶的上胚为处理对象,从秋水仙素浓度50mg/L,处理时间7d开始有较低的加倍率,以秋水仙素浓度100mg/L处理时间7d的加倍效果最好,为10.9%.细胞染色体鉴定结果为:四倍体染色体数为2n=4x=32;而二倍体的染色体数为2n=2x=16.