基于高阶空间精度格式和嵌套网格对旋翼尾迹捕捉的改进

发展了一种基于高阶迎风格式和嵌套网格捕捉直升机悬停旋翼涡尾迹的方法.无粘通量采用Roe Reimann求解器,使用改进的5阶加权基本无振荡(WENO)格式对交界面左右状态进行高阶插值,并与MUSCL插值进行比较.为便于捕捉尾迹和实施周期性边界条件,计算采用结构嵌套网格,其中高质量的旋翼网格完全嵌套于背景网格中.当解达到近似收敛后在桨尖涡分布区域对背景网格进行加密,如此经过3次得到优化的背景网格.考虑到WENO格式插值的特点,提出了搜索3层洞边界和人工外边界的方法以便插值的直接进行.用该方法对一跨音速和一亚音速悬停旋翼粘性流场进行了数值计算.数值结果表明:所发展方法对涡尾迹具有很高的捕捉能力;与MUSCL格式相比,WENO格式具有较低的数值耗散.     

Economic partnering with the poor: why local governments should work with community-based development organizations to promote economic development

Much of conventional economic development ends up as a transfer of wealth from the public sector to successful firms. Instead, local governments would be better off working to support the efforts of community-based development organizations to expand the economic pie for those most in need. Suggestions are made of ways to bring about equity development programs that would help those most in need rather than merely subsidizing established businesses.     

Punishment's Legal Templates: A Theory of Formal Penal Change

The well‐known gap between law on the books and law in action often casts doubt on the significance of changes to law on the books. For example, the rise and fall of penal technologies have long been considered significant indicators of penal change in socio‐historical analyses of punishment. Recent research, however, has challenged the significance of apparently large‐scale penal change of this kind. This article clarifies the significance of penal technologies' rise and fall by offering an alternative account of formal penal change, introducing the analytical concept of “legal templates,” structural models of legal activity (e.g., punishment) available for authorization and replication across multiple jurisdictions. Analyzing punishment's templates explains how new penal technologies can be important harbingers of change, even when they fail to revolutionize penal practice and are not caused by a widespread ideological shift. This article locates the significance of punishment's legal templates in their constitutive power—their ability, over the long term, to shape cognitive‐cultural expectations about what punishment is or should be. This power appears only when the template is widely adopted by a plurality of jurisdictions, thereby becoming institutionalized. Ultimately, these institutionalized templates define the scope of future punishment.     

Term Limits,Campaign Contributions,and the Distribution of Power in State Legislatures

Using campaign contributions to legislators as an indicator of member influence, we explore the impact of term limits on the distribution of power within state legislatures. Specifically, we perform a cross‐state comparison of the relative influence of party caucus leaders, committee chairs, and rank‐and‐file legislators before and after term limits. The results indicate that term limits diffuse power in state legislatures, both by decreasing average contributions to incumbents and by reducing the power of party caucus leaders relative to other members. The change in contribution levels across legislators in different chambers implies a shift in power to the upper chamber in states with term limits. Thus, the impact of term limits may be attenuated in a bicameral system.