Skip to main content Accessibility help

Pressure fluctuations on an oscillating trailing edge

  • Thomas Staubli (a1) (a2) and Donald Rockwell (a1)

Turbulent boundary layers separating from a blunt trailing edge give rise to organized vortical structures in the downstream wake. The perturbation of this inherent flow-instability at f0 by controlled oscillations of the edge at fe produces corresponding, organized components of unsteady surface pressure along the edge. For edge excitation near the ‘natural’ vortex shedding frequency f0, the phase between the local pressure fluctuations and the edge displacement shows large changes for small changes in excitation frequency. Moreover, in this range of excitation, there is quenching (or attenuation) of the surface pressure component at f0 and resonant peaking of the component at fe. These phenomena are related to the change in sign of the energy transfer between the fluid and the body. Integration of the instantaneous pressure distributions along the surfaces of the edge leads to the instantaneous lift at fe and f0 acting upon the oscillating trailing edge. The location of the lift varies as the cotangent of the dimensionless time during an oscillation cycle. When the edge is excited near, or at, the natural vortex shedding frequency, there is a resonant peak in the amplitude of oscillation of the lift location at fe; that at f0 is invariant. Moreover, the mean location of the lift at fe undergoes abrupt changes in this region of excitation. Flow visualization allows determination of the phasing of the organized vortical structures shed from the trailing edge relative to the edge displacement. Modulation of the flow structure at the frequencies f0 and fe, as well as interaction of small-scale vortices at high excitation frequencies, was observed. These aspects of the near-wake structure are related to the instantaneous pressure field.

Hide All
Abernathy, F. & Kronauer, R. E., 1962 The formation of vortex streets. J. Fluid Mech. 13, 120.
Archibald, F. S.: 1975 Unsteady Kutta condition at high values of the reduced frequency parameter. J. Aircraft 12, 545550.
Bearman, P. W.: 1967 On vortex street wakes. J. Fluid Mech. 28, 625641.
Bearman, P. W.: 1984 Vortex shedding from oscillating bluff bodies. Ann. Rev. Fluid Mech. 16, 195222.
Bearman, P. W. & Currie, I. G., 1979 Pressure fluctuation measurements on an oscillating circular cylinder. J. Fluid Mech. 91, 661677.
Bearman, P. W. & Obasaju, E. D., 1982 Vortex shedding from bluff bodies in oscillatory flow. J. Fluid Mech. 99, 225245.
Berger, E. & Wille, R., 1972 Periodic flow phenomena. Ann. Rev. Fluid Mech. 4, 313340.
Bishop, R. E. D. & Hassan, A. Y. 1964 The lift and drag forces on a circular cylinder oscillating in a flowing fluid. Proc. R. Soc. Lond. A 277, 5175.
Bisplinghoff, E. H., Ashley, H. & Halfman, R. L., 1955 Aeroelasticity. Addison Wesley.
Blake, W. K.: 1984 Trailing edge flow and aerodynamic sound: Part 1, Tonal pressure and velocity fluctuations. David W. Taylor Naval Ship research and Development Center, Rep. DTNSRDC-83/113.
Blake, W. K.: 1984 Trailing edge flow and aerodynamic sound: Part 2, Random pressure and velocity fluctuations. David W. Taylor Naval Ship Research and Development Center, Rep. DTNSRDC-83/113.
Blake, W. K. & Maga, L. J., 1979 Near wake structure and unsteady pressures at trailing edges of airfoils. Proc. Joint IUTAM/ICA/AIAA Symposium on Mechanics of Sound Generation in Flows (ed. E.-A. Mueller), pp. 6975. Springer.
Brepson, R. & Leon, P., 1972 Vibrations induced by von Kármán vortex trail in guide vanes. IUTAM–IAHR Symp. Karlsruhe 1972, Flow-Induced Vibrations (ed. E. Naudascher), pp. 318332. Springer.
Feng, C. C.: 1968 The measurement of vortex-induced effects on flow past stationary and oscillating circular and D-section cylinders. M. A. Sc. thesis, University of British Columbia.
Fiedler, H. E. & Mansing, P., 1985 The plane turbulent shear layer with periodic excitation. J. Fluid Mech. 150, 281309.
Gerrard, J. H.: 1978 The wakes of cylindrical bluff bodies at low Reynolds number. Phil. Trans. R. Soc. Lond. A 288, 351389.
Graham, J. M. R. & Maull, D. J. 1971 The effects of an oscillating flap and an acoustic resonance on vortex shedding. J. Sound Vibr. 18, 371380.
Greenway, M. E. & Wood, C. J., 1973 The effect of a bevelled trailing edge on vortex shedding and vibration. J. Fluid Mech. 61, 323335.
Griffin, O. M. & Ramberg, S. E., 1974 The vortex-street wakes of vibrating cylinders. J. Fluid Mech. 66, 553576.
Johansen, J. B. & Smith, C. R., 1983 The effects of cylindrical surface modifications on turbulent boundary layers. Rep. FM-3, Lehigh University, Department of Mechanical Engineering & Mechanics, Bethlehem, PA 18015.
Koch, W.: 1985 Local instability characteristics and frequency determination of self-excited wake flows. J. Sound Vibr. 99, 5383.
Mair, W. A. & Maull, D. J., 1971 Bluff bodies and vortex shedding – a report on Euromech 17. J. Fluid Mech. 45, 209224.
Monkewitz, P. A. & Nguyen, L. M., 1987 Absolute instability in the near-wake of two-dimensional bluff bodies. J. Fluids Structures 1, 165184.
Morkovin, M.: 1964 Flow around circular cylinder – a kaleidoscope of challenging fluid phenomena. Proc. ASME Symposium on Fully Separated Flows, Philadelphia, pp. 102118.
Ongoren, A. & Rockwell, D., 1988 Flow structure from an oscillating cylinder. Part 1. Mechanisms of phase shift and recovery of the near-wake. J. Fluid Mech. 191, 197223.
Purtell, L. P. & Klebenoff, P. S., 1981 Turbulent boundary layer at low Reynolds number. Phys. Fluids 24, 802811.
Roshko, A.: 1954 On the drag and shedding frequency of two-dimensional bluff bodies. NACA Tech. Note 3169.
Saffman, P. G. & Schatzman, J. C., 1982 An inviscid model for the vortex street wake. J. Fluid Mech. 122, 467486.
Sarpkaya, T.: 1978 Fluid forces on oscillating cylinders. J. Waterway, Port, Coastal Ocean Engng Div. ASCE 104 (WW4), 275290.
Sarpkaya, T.: 1979 Fluid forces on oscillating cylinders, a selective review. Trans. ASME E: J. Appl. Mech. 26, 241258.
Schewe, G.: 1983 On the structure and resolution of wall-pressure fluctuations associated with turbulent boundary-layer flow. J. Fluid Mech. 134, 311328.
Schlichting, H.: 1979 Boundary Layer Theory. McGraw-Hill.
Staubli, T.: 1981 Calculation of the vibration of an elastically mounted cylinder using experimental data from a forced oscillation. In ASME Symp. on Fluid–Structure Interaction in Turbomachinery, pp. 1924.
Staubli, T.: 1983 Untersuchung der oszillierenden Kräfte am querangestrõmten, schwingenden Kreiszylinder. Dissertation ETH 7322.
Staubli, T.: 1987 Entrainment of self-sustained flow oscillations: phase-locking or asynchronous quenching? Trans. ASME E: J. Appl. Mech. 54, 706712.
Unal, M. F. & Rockwell, D., 1988 On vortex formation from a cylinder. Part 1. The initial instability. J. Fluid Mech. 190, 491512.
Wood, C. J.: 1971 The effect of lateral vibrations on vortex shedding from blunt-based aerofoils. J. Sound Vib. 14, 91102.
Zdravkovich 1982 Modification of vortex shedding in the synchronization range. Trans. ASME I: J. Fluids Engng, 104, 513517.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Journal of Fluid Mechanics
  • ISSN: 0022-1120
  • EISSN: 1469-7645
  • URL: /core/journals/journal-of-fluid-mechanics
Please enter your name
Please enter a valid email address
Who would you like to send this to? *


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed