Silicon micromachined magnetic actuators for aerodynamic flow control applications

Citation

Tsao, Thomas Rocco (1998) Silicon micromachined magnetic actuators for aerodynamic flow control applications. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/z29s-kt20. https://resolver.caltech.edu/CaltechETD:etd-02052008-112354

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. Active micro-scale flow control has been a long sought-after goal of fluid mechanists. One of the primary desires within this field is to control macroscopic events with microscopic forces. Recent research has provided shear stress sensors capable of detecting micro-scale structures present in aerodynamic flows. In this work, the results (fabrication, device testing, fluidic testing) of developing magnetic actuators to interact with and affect the flow are reported. A first attempt at [...] (microsensor, mielodetuator, and microelectronic) integration is also presented. One of the primary aerodynamic motivations is the control of the rolling moment of delta wing aircraft. For the demonstration of such an application, a line of flaps on a leading edge of the wing should be activated simultaneously. Therefore, arrays of passive magnetic flaps were fabricated and successfully used to create significant rolling moments in wind tunnel testing of delta wings. The other motivation in the development of magnetic flaps is the reduction of drag in turbulent boundary layers. To succeed in this effort, the actuators must interact with, and negate the effects of, millimeter sized turbulent structures. Due to the unpredictable nature of such structures, each flap across a control surface should be individually addressable. Many designs of actively controlled magnetic flaps were fabricated and tested. The various generations were designed not only with device performance in mind, but also eventual integration with sensors and electronics. To this end, several fabrication issues, most notably dealing with the sacrificial layer, are presented. Finally, a first attempt at integrating sensors, actuators, and electronics on one substrate is presented. Such an effort is crucial both for the eventual use in flow control applications as well as in other generic MEMS/electronics integration efforts.

Thesis Files