Aerodynamics and Design for Ultra-Low Reynolds Number Flight

Chapter 8
Conclusions and Recommendations
Achieving powered flight at ultra-low Reynolds numbers and true micro-aircraft scales
requires a greater understanding of aerodynamics in a flow regime that, until now, has
only been minimally explored. The goals of this research have been to broadly explore
the aerodynamics of this environment and then to use the insight gained to analyze,
design, manufacture, and test micro-rotors of an unprecedented small physical scale. In
the culmination of this effort, micro-rotorcraft have been proposed and developed that
represent both the current state-of-the art and what lies just beyond it.
8.1 Summary of Results and Contributions in the
Area of Two-Dimensional Aerodynamics
Airfoils in this regime face unique operating conditions and the two-dimensional
computational study represents the first comprehensive and quantitative exploration of
the airfoil design space at ultra-low Reynolds numbers. Under these conditions, the flow
is dominated by viscous effects and the growth of thick boundary layers causes
significant modifications to the effective geometry of the section. This effective loss of
camber is exacerbated by the fact that flow separation occurs at low angles of attack.
However, the onset of separation does not have to have the same catastrophic
169