Wing flapping is one of the most widespread propulsion methods found in nature; however, the current understanding of the aerodynamics in bird wakes is incomplete. The role of the unsteady motion in the flow and its contribution to the aerodynamics is still an open question. In the current study, the wake of a freely flying European starling has been investigated using long-duration high-speed ...

In this talk, we consider the well-posedness, ill-posedness and the regularity of stationary solutions to the hydrodynamic model of semiconductors represented by Euler-Poisson equations with sonic boundary, and make a classification on these solutions. When the doping profile is subsonic, we prove that, the corresponding steady-state equations with sonic boundary possess a unique interior subso...

Aerodynamics curriculum in undergraduate engineering has reached a critical juncture forcing the need for change in the traditional, largely theoretical curriculum and lecturer/listener pedagogy. The role of aerodynamics in aerospace engineering, while still important, is no longer the dominant driver in aircraft design. Furthermore, industry, government, and academia --the likely employers of ...

Historically, the design of subsonic and supersonic aircraft has been divided into separate technical disciplines (such as propulsion, aerodynamics and structures), each of which performs design and analysis in relative isolation from others. This is possible, in most cases, either because the amount of interdisciplinary coupling is minimal, or because the interactions can be treated as linear....

This paper studies the liquid to vapor phase transition in a cone shaped nozzle. Using the geometric method presented in [32, 34], we further develop results on subsonic and supersonic evaporation waves in [14] to transonic waves. It is known that transonic waves do not exist if restricted solely to the slow system on the slow manifolds [14]. Thus we consider the existence of transonic waves th...

The hydrodynamic model for semiconductors in one dimension is considered. For perturbated Riemann data, global subsonic (weak) entropy solutions, piecewise continuous and piecewise smooth solutions with shock discontinuities are constructed and their asymptotic behavior is analyzed. In subsonic domains, the solution is smooth and, exponentially as t —> oo, tends to the corresponding stationary ...

Active flow control of cavity tones has been successful in controlling Rossiter tones in both subsonic and supersonic flows. While closed-loop control promises the lowest actuator power requirements and the ability to adapt to changing flow conditions, so far it has only been demonstrated on subsonic cavities. Suppression of Rossiter tones in supersonic cavities has been demonstrated using open...