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Computational Study of a Plate Mounted Finite Cylinder: Aspect Ratio and Boundary Layer Thickness Effects
Hummer, Christopher J

, MS, University of Cincinnati, Engineering and Applied Science: Aerospace Engineering.
The integration of protrusions on aircraft, whether they are antennas or sensor
turrets, can impact both aircraft safety and performance. The protrusions vary in size
and shape and where they are placed on the aircraft can greatly affect the flow around
the structure. This work utilizes the power and adaptability of modern computational
methods to analyze finite cylinders of various aspect ratios subjected to incoming flow
of varying boundary layer thickness. The geometry and flow conditions for the analysis
match a wind tunnel test completed by the University of Cincinnati in 2005. This
flow is challenging to model computationally because the flow is largely separated
and influenced by both ends of the cylinder. The four cylinders analyzed, labeled by
their diameter and height in inches, are D2H5, D4H2, D4H5, and D4H10. These four
cylinders were subjected to cross-flows with two different boundary layer thicknesses
for a total of eight cases. The boundary layer thicknesses were 1.5” and 6.0”. This
work compared the computational results with both the wind tunnel results and
with available literature. The results compared favorably with both and captured all
primary flow features for this class of flows. Furthermore, the impacts of cylinder
aspect ratio and boundary layer thickness were evident in the results. The lower the
aspect ratio of the cylinder, the more the flow from the free-end dominates the wake.
Higher aspect ratio cylinders can be divided into regions with juncture flow near the
wall, Karman style shedding near the middle and free-end effects near the tip. This
work also identifies a transitional cylinder aspect ratio where the flow transitions
from segregated regions to being dominated by the free-end downwash. This work
shows that modern computational methods are capable of modelling the complex flow
about a finite cylinder and can provide valuable insight to aid in protrusion design
and integration.
Ephraim Gutmark, Ph.D. D.Sc. (Committee Chair)
David Munday, Ph.D. (Committee Member)
Mark Turner, Sc.D. (Committee Member)
203 p.

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Hummer, C. (). Computational Study of a Plate Mounted Finite Cylinder: Aspect Ratio and Boundary Layer Thickness Effects. (Electronic Thesis or Dissertation). Retrieved from https://etd.ohiolink.edu/

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Hummer, Christopher. "Computational Study of a Plate Mounted Finite Cylinder: Aspect Ratio and Boundary Layer Thickness Effects." Electronic Thesis or Dissertation. University of Cincinnati, . OhioLINK Electronic Theses and Dissertations Center. 04 Jul 2015.

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Hummer, Christopher "Computational Study of a Plate Mounted Finite Cylinder: Aspect Ratio and Boundary Layer Thickness Effects." Electronic Thesis or Dissertation. University of Cincinnati, . https://etd.ohiolink.edu/

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