Unsteady Turbulent Skin Friction and Separation Location Measurements on a Maneuvering Undersea Vehicle


Steady and unsteady flow over a generic Suboff model is studied. The skin friction magnitudes are measured by using hot-film sensors each connected to a constant temperature anemometer. The local minima in the skin friction magnitudes are used to obtain the separation locations. Steady results are presented for two model configurations: barebody and sail-on-side case. Unsteady results are given for the barebody case. The dynamic plunge-pitch-roll model mount (DyPPiR) is used to simulate the pitchup maneuvers. The pitchup maneuver is a linear ramp from 1° to 27° in 0.33 seconds. Steady results show that the flow structure on the leeward side of the barebody can be characterized by the crossflow separation. In the sail-on-side case, the separation pattern of the non-sail region follow the barebody separation trend closely. The flow on the sail side is strongly affected bythe presence of the sail and the separation pattern is different from the crossflow separation. Unsteady results show significant time lags between unsteady and steady separation locations. These effects produce the difference in separation topology between the unsteady and steady flowfields. A first-order time lag model approximates the unsteady separation locations reasonably well and time lags are obtained by fitting the model equation with the experimental data.

Meeting Name

39th Aerospace Sciences Meeting and Exhibit, AIAA ARC (2001: Jan. 8-11, Reno, NV)


Mechanical and Aerospace Engineering

Document Type

Article - Conference proceedings

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© 2001 American Institute of Aeronautics and Astronautics (AIAA), All rights reserved.

Publication Date

11 Jan 2001