Three-dimensional structure of a low-Reynolds-number turbulent boundary layer

A low-Reynolds-number zero-pressure-gradient incompressible turbulent boundary layer was investigated using a volumetric imaging technique. The Reynolds number based on momentum thickness was 700. The flow was tagged with a passive scalar from two spanwise dye slots to distinguish between fluid motions originating in the inner and outer portions of the boundary layer. The resulting volumetric scalar field was interrogated using a laser sheet scanner developed for this study. Two- and three-dimensional time-dependent visualizations of a 50 volume time series are presented (equivalent to 17δ in length). In the outer portion of the boundary layer, scalar structures were observed to lie along lines in the (x, z)-plane, inclined to the streamwise (x-)direction in the range ±50°. The ejection of brightly dyed fluid packets from the near-wall region was observed to be spatially organized, and related to the passage of the large-scale scalar structures.Carl J Delo, Richard M Kelson and Alexander J Smit

Effects of the Shuttle Orbiter fuselage and elevon on the molecular distribution of water vapor from the flash evaporator system

A concern has arisen regarding the emissive distribution of water molecules from the shuttle orbiter flash evaporator system (FES). The role of the orbiter fuselage and elevon in affecting molecular scattering distributions was nuclear. The effect of these components were evaluated. Molecular distributions of the water vapor effluents from the FE were measured. These data were compared with analytically predicted values and the resulting implications were calculated

Commentary: Legal Education\u27s Future; A Broader Horizon or a Narrowing Window?

The curriculum and perspective of law schools today are broader than they have ever been, especially for students who elect to seek a broad legal education. Even broader legal education is not likely because factors both within and outside the universities point toward a narrowing of law school programs. There is at best an uneven case on the merits for further broadening of legal education

The Constitutional Jurisprudence of Justice Kennedy on Speech

Justice Kennedy\u27s basic principles in free speech cases are supporting political freedom, supporting individual autonomy, and protecting freedom to teach, learn, and innovate. Given these principles, his opinions in free speech cases protect free speech from government regulation unless the government can provide strong reasons for any restrictive action and show that the means it has chosen to carry out its purposes are closely tailored to its goals. At a minimum, judicial review is by strict scrutiny for content-based regulations and intermediate review for content-neutral time, place, and manner regulations. In some cases, Justice Kennedy has indicated a preference for a stronger, absolute rule of unconstitutionality for content-based regulations that do not fall into one of the traditional exceptions of free speech doctrine, such as obscenity, defamation, words tantamount to an act otherwise criminal, impairing some other constitutional right, an incitement to lawless action, or speech calculated to bring about imminent harm that the state has substantive power to regulate. Given his entire body of decisions regarding the freedom of speech over his quarter century on the Court, no Justice on the modern Court has been more consistently protective of the First Amendment freedom of speech than Justice Kennedy