Boundary-layer bleed has conventionally been used to control separation due to shock wave/boundary-layer interactions within supersonic engine inlets. However, bleed systems result in a loss of captured mass flow, incurring higher drag and, ultimately, lower propulsion system efficiency. Microramp sub-boundary-layer vortex generators arranged in a spanwise array have been proposed in the past as a form of flow-control methodology for shock wave/ boundary-layer interactions. Experiments have been conducted herein at Mach 1.4 to characterize flow details of such devices and obtain quantitative measurements of their ability to control the interaction of a normal shock with a turbulent boundary layer. The flowfield was analyzed using schlieren photography, surface oil flow visualization, pressure-sensitive paint, and particle image velocimetry. An array of three microramps, for which the height was scaled to 36% of the incoming boundary-layer thickness, was placed ahead of the normal shock interaction. It was demonstrated that the microramps did entrain higher-momentum fluid into the boundary layer, which improved boundary-layer health. Specifically, the incompressible displacement thickness, momentum thickness, and shape factor were decreased, and the skin friction coefficient was increased, for the shock wave/boundary-layer interaction with the microramp array relative to the no-array case.

The Lower Atmosphere/Ionosphere Coupling Experiment (LAICE) CubeSat mission will focus on understanding the interaction of atmospheric gravity waves generated by weather systems in the lower atmosphere with the mesosphere, lower thermosphere, and ionosphere (MLTI). Specifically, LAICE will focus on the energy and momentum delivered by these waves and attempt to connect the wave sources and the wave effects in three widely different altitude ranges, substantially adding to our knowledge of critical coupling processes between disparate atmospheric regions. The LAICE mission consists of a 6U CubeSat with a four-instrument payload. The retarding potential analyzer (RPA) will provide in-situ ion density and temperature measurements. A four-channel photometer will measure density and temperature variations in the mesosphere through observations of O 2 (0,0) Atmospheric band and O 2 Herzberg I band airglows. There are two pressure sensors that comprise the Space Pressure Suite (SPS): the Space Neutral Pressure Instrument (SNeuPI) and the LAICE Ionization gauge Neutral Atmosphere Sensor (LINAS). Both will provide neutral density measurements, but SNeuPI is a prototype sensor that will be validated by LINAS. This CubeSat mission, scheduled for launch in early 2016 from the International Space Station, provides a cost-effective approach to measuring low altitude in-situ parameters along with simultaneous imaging that is capable of addressing the fundamental questions of atmospheric gravity wave coupling in the MLTI region.

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