Supersonic Boundary Layer in Regions with Small Temperature Perturbations on the Wall
The problem of disturbed flow in the laminar boundary layer when heating elements are located on the surface is investigated. The flow is described by the theory of viscous-inviscid interaction with full Navier–Stokes equations. We apply the triple-deck model of the flow and describe asymptotic multiscale structure for the supersonic case. Using this structure as a base, we construct the solution to the flat stationary problem by means of Fourier transform and analysis in the complex plane. It is also shown that localization of a heating element may arrive at a singularity of the pressure downstream. Results of numerical and analytic analysis are presented. Using these elements gives us the opportunity to develop a novel method for the separation control of the boundary layer.
Stationary subsonic boundary layer in the regions of local heating of surface
The problem of disturbed flow in the laminar boundary layer is investigated when a heating element is located on the surface of the body. The flow is supposed to be laminar one. It is shown that the problem may be solved in terms of free interaction theory. The solution of linear flat problem is constructed. The results of asymptotic analysis are also presented.
Randi Weingarten, the American Federation of Teachers, and the Challenges of Policy Leadership in a Hostile Environment
Randi Weingarten is the president of the most vocal and influential teachers’ union, the American Federation of Teachers. Since rising through the ranks to AFT president in just two years, Weingarten is now a major, if not the most prominent, nongovernmental player in national education policy. She has earned deep respect from many educational policy actors. Likewise, Weingarten elicits withering criticism from others. This fascinating profile explains why, in such a brief period, she has proved to be a fierce, fearless, and effective leader under extraordinarily difficult circumstances. Her experience offers invaluable lessons applicable for others working in similarly intense policy arenas.