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.
Similar content being viewed by others
References
Graham J M R. I C Aero report, 1982
Lian W, Appl Ocean Res, 1988, 10(3)
Ling G, Luo C. Acta Mech Sinica, 1991 7(1)
Chein R., Chung J N. Comput & Fluids, 1988, 16(4)
Kiya M., Arie M. Bull JSME, 1980, 23(1451)
Kamemoto, K. Bearman PW, I C Aero, TN 78-108, 1978
Sarpkaya T, J Fluid Mech, 1975, 68(109)
Armstrong B J, Barnes F H, Phys Fluids, 1986,29 (7)
Author information
Authors and Affiliations
Additional information
The project supported by National Natural Science Foundation of China & LNM, Institute of Mechanics, CAS
Rights and permissions
About this article
Cite this article
Guocan, L., Guohua, L. Flow structures and force characteristics for flat plate in oscillatory flows withKc number from 2 to 40 and in combined flows. Acta Mech Sinica 8, 35–43 (1992). https://doi.org/10.1007/BF02486914
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF02486914