Abstract
A survey of the physical features of steady and unsteady separating turbulent boundary layers is presented for practical Reynolds numbers and reduced frequencies for helicopter and turbomachinery flows. Well upstream of separation there is little interaction between the periodic motions, so the flow away from the wall has little phase variation from the freestream. Near the wall between the viscous sublayer and the semi-logarithmic region, unexpected phase shifts of the velocity and turbulence oscillations occur.
Near separation and downstream more interaction occurs between the periodic and turbulent motions since the characteristic frequency of the large scale structures is much lower than upstream. Significant phase variations between the velocity and turbulence exist in the detached and back flows. For moderate oscillation amplitudes there is no effect of oscillation waveform on the mean flow features. Large amplitude oscillations affect the flow structure significantly.
Keywords
- Turbulent Boundary Layer
- Eddy Viscosity
- Freestream Velocity
- Sinusoidal Waveform
- Large Amplitude Oscillation
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsPreview
Unable to display preview. Download preview PDF.
References
Simpson, R.L., “A Review of Some Phenomena in Turbulent Flow Separation,” in press, J. Fluids Engrg., 1981.
Simpson, R.L., Shivaprasad, B.G., and Chew, Y-Y., “Measurements of Unsteady Turbulent Boundary Layers with Pressure Gradients,” Rept. WT-6, SMU Dept. Civil/Mech. Engrg., 1980; submitted to J. Fluid Mechanics.
Simpson, R.L., Sallas, J.J., and Nasburg, R.E., “Tailoring the Waveform of a Periodic Flow with a Programmable Damper,” J. Fluids Engrg., 100, pp. 287–290, 1978.
Simpson, R.L. and Chew, Y.-T., “Measurements in Highly Turbulent Flows: Steady and Unsteady Separated Turbulent Boundary Layers,” Proceedings of Third Int. Workshop on Laser Velocimetry, pp. 179–196, Hemisphere, 1979.
Rubesin, M.W., Okuno, A.F., Mateer, G.G., and Brosh, A., “A Hot-Wire Surface Gage for Skin Friction and Separation Detection Measurements,” NASA TM X - 62, 465, 1975.
Eaton, J.K., Jeans, A.H., Ashjaee, J., and Johnston, J.P., “A Wall-Flow- Direction Probe for Use in Separating and Reattaching Flows,” J. Fluids Engrg., 101, pp. 364–366, 1979.
Shivaprasad, B.G. and Simpson, R.L., “Evaluation of an Improved Wall- Flow-Direction Probe for Measurements in Separated Flows,” submitted to J. Fluids Engrg.
Simpson, R.L., Chew, Y.-T., and Shivaprasad, B.G., “The Structure of a Separating Turbulent Boundary Layer: Part I, Mean Flow and Reynolds Stresses; Part II, Higher Order Turbulence Results,” both in press, J. Fluid Mechanics.
Shiloh, K., Shivaprasad, B.G., and Simpson, R.L., “The Structure of a Separating Turbulent Boundary Layer III: Transverse Velocity Measurements,” in press, J. Fluid Mechanics.
Perry, A.E. and Schofield, W.H., “Mean Velocity and Shear Stress Distribution in Turbulent Boundary Layers,” Physics Fluids, 16, pp. 2068–2074, 1973.
Simpson, R.L., “Features of Unsteady Turbulent Boundary Layers as Revealed from Experiments,” paper 19, Symposium on Unsteady Aerodynamics, NATO-AGARD, Ottawa, Canada, Sept. 1977, AGARD-CP-227.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1981 Springer-Verlag, Berlin, Heidelberg
About this paper
Cite this paper
Simpson, R.L., Shivaprasad, B.G., Chew, YT. (1981). Some Features of Unsteady Separating Turbulent Boundary Layers. In: Michel, R., Cousteix, J., Houdeville, R. (eds) Unsteady Turbulent Shear Flows. International Union of Theoretical and Applied Mechanics. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-81732-8_10
Download citation
DOI: https://doi.org/10.1007/978-3-642-81732-8_10
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-81734-2
Online ISBN: 978-3-642-81732-8
eBook Packages: Springer Book Archive