Title page for ETD etd-04162009-161320


Type of Document Dissertation
Author Granlund, Kenneth Ove
Author's Email Address granlund@vt.edu
URN etd-04162009-161320
Title Steady and Unsteady Maneuvering Forces and Moments on Slender Bodies
Degree PhD
Department Aerospace and Ocean Engineering
Advisory Committee
Advisor Name Title
Simpson, Roger L. Committee Chair
Devenport, William J. Committee Member
Mason, William H. Committee Member
McCue-Weil, Leigh S. Committee Member
Woolsey, Craig A. Committee Member
Keywords
  • unsteady
  • ellipsoid
  • separation
  • signal processing
  • vortical
  • experiment
  • slender
Date of Defense 2009-02-06
Availability unrestricted
Abstract
Forces and moments have been measured on slender bodies in both static angle conditions as well as rapid time-dependent large amplitude maneuvers with the Dynamic Pitch Plunge Roll (DyPPiR) apparatus.



Lateral and transversal forces as well as all three moments have been measured at static angles of attack and sideslip and unsteady pitch ramp maneuvers at a fixed point of rotation at the quarter length of the body. The two bodies are the DARPA Suboff generic submarine shape and a non-Body-of-Revolution scalene ellipsoid with a constant cross-section midbody.

An analytical two-mode equation has been shown to accurately describe the normal force and pitch moment as well as side force and yaw moment for the ellipsoid body. It is based on the observation that the center of pressure for the cross-flow contribution is at a fixed location. For the Suboff body, this assumption is invalid. Unsteady forces and moments can be measured to a very small magnitude of uncertainty and were found to differ from steady forces and moments at the time-instantaneous flow angle during the motion.

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