ISSN:
1614-3116
Keywords:
flow structure
;
force coefficients
;
oscillatory flow
;
combined flow
;
that plate
;
discrete vortex method
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract The evolution of wake structures and variation of the forces on a flat plate in harmonic oscillatory and in-line combined flows are obtained numerically by improved discrete vortex method. For the oscillatory oncoming flow cases, wyenKc number varies from 2 to 40, the vortex pattern changes from a “harmonic wave” shaped (in a range of smallKc number) to a slight inclined “harmonic wave” shaped (in a range of moderateKc numbers), then to inclined vortex clusters with an angle of 50° to the oncoming flow direction (atKc=20), at last, asKc number becomes large, the vortex pattern is like a normal Karman vortex street. The well predicted drag and inertia force coefficients are obtained, which are more close to the results of Keulegan & Carpenter's experiment as compared with previous vortex simulation by other authors. The existence of minimum point of inertia force coefficientC m nearKc=20 is also well predicted and this phenomenon can be interpreted according to the vortex structure. For steady-oscillatory in-line combined flow cases, the vortex modes behave like a vortex street, exhibit a “longitudinal wave” structure, and a vortex cluster shape corresponding to the ratios ofU m toU 0 which are ofO (10−1)O(1) andO(10), respectively. The effect on the prediction of forces on the flat plate from the disturbance component in a combined flow has been demonstrated qualitatively. In addition to this, the lock in phenomenon of vortex shedding has been checked.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02486914
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