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Measurements of lift in oscillatory flow

Published online by Cambridge University Press:  21 April 2006

G. N. Rosenthal  and
J. F. A. Sleath
G. N. Rosenthal
Affiliation:
Department of Engineering, University of Cambridge Present address: Department of Civil Engineering, University of Cape Town.
J. F. A. Sleath
Affiliation:
Department of Engineering, University of Cambridge
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Abstract

Measurements are reported of the lift on a sphere in oscillatory flow. Two different oscillating-tray rigs were used and measurements were made for a sphere at various distances from both smooth and rough beds. For the rough bed, the roughness consisted of a single close-packed layer of similar spheres glued to the surface of the tray. Both smooth and rough beds showed somewhat similar trends. At sufficiently low Reynolds numbers the lift varied smoothly during the course of the cycle with maxima near the point at which fluid velocity was greatest and minima near velocity reversal. However, at higher Reynolds numbers a secondary peak began to appear near the point of velocity reversal. It is suggested that this secondary peak may be associated with vortex formation around the sphere. When the sphere diameter D was large compared with the viscous-boundary-layer lengthscale 1/β(= (2ν/ω)½), the maximum value of CL during the course of a half-cycle initially increased with increasing Reynolds number, reached a maximum, and then declined steadily. The curves were similar for smaller βD-values except that the tests did not extend to low enough Reynolds numbers to show the initial rise. For the smaller values of βD the lift record became unstable when the Keulegan–Carpenter number exceeded approximately 244. At higher βD-values it was not possible to observe any significant instability for the range of Reynolds numbers investigated.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 164 , March 1986 , pp. 449 - 467
Copyright
© 1986 Cambridge University Press

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References

Aksoy, S. 1973 Fluid force acting on a sphere near a solid boundary. In Proc. 15th IAHR Cong., Istanbul, pp. 217–224.
Auton, T. R. 1984 The dynamics of bubbles, drops and particles in motion in liquids. Ph.D. dissertation, Cambridge University.
Bagnold, R. A. 1974 Fluid forces on a body in shear flow; experimental use of stationary flow. Proc. R. Soc. Land. A 340, 147–171.Google Scholar
Carstens, M. R. 1952 Accelerated motion of a spherical particle. Trans. Am. Geophys. Union 33, 713–721.Google Scholar
Chen, C. & Caestens, M. R. 1973 Mechanics of removal of a spherical particle from a flat bed. In Proc. 15th IAHR Cong., Istanbul, pp. 147–158.
Chepil, W. S. 1961 The use of spheres to measure lift and drag on wind-eroded soil grains. Proc. Soil Sci. Soc. 5, 343.Google Scholar
Coleman, N. L. 1967 A theoretical and experimental study of drag and lift forces acting on a sphere resting on a hypothetical streambed. In Proc. 12th Congress IAHR Fort Collins, pp. 185–192.
Davies, T. R. H. & Samad, M. F. A. 1978 Fluid dynamic lift on a bed particle. Proc. A8CE J. Hydraul. Div. 104, 1171–1182.Google Scholar
Duw Toit, C. G. & Sleath, J. F. A. 1981 Velocity measurements close to rippled beds in oscillatory flow. J. Fluid Mech. 112, 71–96.Google Scholar
Lee, K. C. 1979 Aerodynamic interaction between two spheres at Reynolds numbers around 104. Aero. Q. 15, 371–385.Google Scholar
Maull, D. J. & Milliner, M. G. 1978 Forces on a circular cylinder having a complex periodic motion. In Mechanics of Wave-Induced Forces on Cylinders (ed. T. L. Shaw), pp. 490–502. Fearon Pitman.
Maull, D. J. & Norman, S. J. 1978 A horizontal circular cylinder under waves. In Mechanics of Wave-Induced Forces on Cylinders (ed. T. L. Shaw), pp. 359–378. Fearon Pitman.
Milne Thomson, L. M. 1968 Theoretical Hydrodynamics. 5th edn. Macmillan.
Naheer, E. 1977 Stability of bottom armoring under the attack of solitary waves. Calif. Inst. of Tech. W. M. Keck Lab. Rep. Kh-R-34.Google Scholar
Rosenthal, G. N. 1986 Lift forces on spherical particles near a horizontal bed in oscillatory flow. Ph.D. dissertation, Cambridge University.
Rubinow, S. I. & Keller, J. B. 1961 The transverse force on a spinning sphere moving in a viscous fluid. J. Fluid Mech. 11, 447–459.Google Scholar
Saffman, P. G. 1965 The lift on a small sphere in a slow shear flow. J. Fluid Mech. 22, 385–400 (and Corrigendum 31 (1968), 624).Google Scholar
Sarpkaya, T. 1975 Forces on cylinders and spheres in a sinusoidally oscillating fluid. Trans. ASME E: J. Appl. Mech. 42, 32–37Google Scholar
Sarpkaya, T. 1976 Forces on cylinders near a plane boundary in a sinusoidally oscillating fluid. Trans. ASMS I: J. Fluids Engng 98, 499–505Google Scholar
Sert, M. 1977 The force on a particle near a bed acted upon by water waves. Ph.D. dissertation, Cambridge University.
Sleath, J. F. A. 1973 A numerical study of the influence of bottom roughness on mass transport by water waves. In Numerical Methods in Fluid Dynamics (ed. C. A. Brebbia and J. J. Connor). Pentech Press.
Swanson, W. M. 1961 The Magnus effect: a summary of investigations to date. Trans. ASMS D: J. Basic Engng 83, 461–470Google Scholar
Thomschke, H. 1971 Experimentelle Untersuchung der stationären Umströmung von Kugel und Zylinder in Wandnähe. Doctoral thesis, Karlsruhe University.
Willetts, B. B. & Murray, C. G. 1981 Lift exerted on stationary spheres in turbulent flow. J. Fluid Mech. 105, 487–505.Google Scholar
Willmarth, W. W. & Enlow, R. L. 1969 Aerodynamic lift and moment fluctuations of a sphere. J. Fluid Mech. 36, 417–432.Google Scholar
Young, D. F. 1960 Drag and lift on spheres within cylindrical tubes. Proc. A8CE J. Hydraul. Div. 86, 47.Google Scholar