This paper presents experimental results on the internal flow structure of turbulent spots, and examines the sensitivity of this structure to streamwise acceleration rate and freestream turbulence. Measurements were performed on a flat plate, with two levels of freestream acceleration rate and three levels of freestream turbulence. The turbulent spots were generated artificially at a fixed distance from the test-surface leading edge, and the development of the spot was documented through hotwire measurements at three streamwise locations. The measurements were performed at multiple spanwise locations to allow observation of the three-dimensional spatial structure of the turbulent spot and the temporal evolution of this structure. Analysis of the perturbation velocity and rms velocity fluctuations provides insight into the variations of the streaky streamwise-velocity structure within the turbulent spot, with a focus on the effects of freestream acceleration rate and turbulence level.
Issue Section:
Technical Papers
1.
Emmons
, H. W.
1951, “The Laminar-Turbulent Transition in a Boundary Layer
,” J. Aeronaut. Sci.
0095-9812, 18
, pp. 490
–498
.2.
Elder
, J. W.
1960, “An Experimental Investigation of Turbulent Spots and Breakdown to Turbulence
,” J. Fluid Mech.
0022-1120, 9
, pp. 235
–246
.3.
Wygnanski
, I.
, Sokolov
, M.
, and Friedman
, D.
1976, “On a Turbulent Spot in a Laminar Boundary Layer
,” J. Fluid Mech.
0022-1120, 78
, pp. 785
–819
.4.
Coles
, D.
, and Barker
, S. J.
1975, “Some Remarks on a Synthetic Turbulent Boundary Layer
,” in Turbulent Mixing in Nonreactive and Reactive Flows
, S. N. B.
Murthy
, ed., Plenum Press, New York, 0.75pp. 285
–293
.5.
Cantwell
, B.
, Coles
, D.
, and Dimotakis
, P.
1978, “Structure and Entrainment in the Plane of Symmetry of a Turbulent Spot
,” J. Fluid Mech.
0022-1120, 87
, pp. 641
–676
.6.
Gad-El-Hak
, M.
, Blackwelder
, F.
, and Riley
, J. J.
1981, “On the Growth of Turbulent Regions in Laminar Boundary Layers
,” J. Fluid Mech.
0022-1120, 110
, pp. 73
–95
.7.
Charters
, A. C.
1943, “Transition Between Laminar and Turbulent Flow by Transverse Contamination
,” NACA Technical Note No. 891.8.
Corrsin
, S.
, and Kistler
, A. L.
1955, “Free-Stream Boundaries of Turbulent Flows
,” NACA Report No. 1244.9.
Sankaran
, R.
, Sokolov
, M.
, and Antonia
, R. A.
1988, “Substructures in a Turbulent Spot
,” J. Fluid Mech.
0022-1120, 197
, pp. 389
–414
.10.
Schröder
, A.
, and Kompenhans
, J.
2004, “Investigation of a Turbulent Spot Using Multi-Plane Stereo Particle Image Velocimetry
,” Exp. Fluids
0723-4864, 36
, pp. 82
–90
.11.
Makita
, H.
, and Nishizawa
, A.
2001, “Characteristics of Internal Vortical Structures in a Merged Turbulent Spot
,” J. Turbul.
1468-5248, 2
, pp. 1
–14
.12.
Zilberman
, M.
, Wygnanski
, I.
, and Kaplan
, R.
1977, “Transitional Boundary Layer Spot in a Fully Turbulent Environment
,” Phys. Fluids
0031-9171, 20
, pp. 258
–271
.13.
Chong
, T. P.
, and Zhong
, S.
2003, “On the Three-Dimensional Structure of Turbulent Spots
,” ASME Paper No. GT-2003-38435.14.
Schubauer
, G. B.
, and Klebanoff
, P. S.
1956, “Contributions on the Mechanics of Boundary Layer Transition
,” NACA Report No. 1289.15.
Moretti
, P. H.
, and Kay
, V. M.
1965, “Heat Transfer in Turbulent Boundary Layer With Varying Free-Stream Velocity and Varying Surface Temperature—An Experimental Study
,” Int. J. Heat Mass Transfer
0017-9310, 8
, pp. 1187
–1202
.16.
Jones
, V. P.
, and Launder
, B. E.
1972, “Some Properties of Sink-Flow Turbulent Boundary Layers
,” J. Fluid Mech.
0022-1120, 56
, pp. 337
–351
.17.
Escudier
, M. P.
, Abdel-Hameed
, A.
, Johnson
, M. W.
, and Sutcliffe
, C. J.
1998, “Laminarization and Retransition of a Turbulent Boundary Layer Subjected to a Favourable Pressure Gradient
,” Exp. Fluids
0723-4864, 25
, pp. 491
–502
.18.
Zhong
, S.
, Kittichaikarn
, C.
, Hodson
, H. P.
, and Ireland
, P. T.
1998, “Visualization of Turbulent Spots Under the Influence of Adverse Pressure Gradients
,” Proceeding of the 8th International Conference on Flow Visualization
, Italy
.19.
Wu
, X.
, Jacobs
, R. G.
, Hunt
, J. C. R.
, and Durbin
, P. A.
1999, “Simulation of Boundary Layer Transition Induced by Periodically Passing Wakes
,” J. Fluid Mech.
0022-1120, 398
, pp. 109
–153
.20.
Kline
, S. J.
, and Robinson
, S. K.
1988, “Quasi-Coherent Structures in the Turbulent Boundary Layer: Part I. Status Report on a Community-Wide Summary of the Data
,” Near Wall Turbulence, 1988 Zoran Zarić Memorial Conference, S. J.
Kline
and N. J.
Afghan
, ed.21.
Piomelli
, U.
, Balaras
, E.
, and Pascarelli
, A.
2000, “Turbulent Structures in Accelerating Boundary Layers
,” J. Turbul.
1468-5248, 1
, pp. 1
–16
.22.
Smith
, C. R.
, and Metzler
, S. P.
1983, “The Characteristics of Low-Speed Streaks in the Near-Wall Region of a Turbulent Boundary Layer
,” J. Fluid Mech.
0022-1120, 129
, pp. 27
–54
.23.
Schraub
, F. A.
, and Kline
, S. J.
1965, “A Study of the Structure of the Turbulent Boundary Layer With and Without Longitudinal Pressure Gradient
,” Report No. MD-12, Thermosciences Division, Stanford University.24.
Talamelli
, A.
, Fornaciari
, N.
, Westin
, K. J. A.
, and Alfredsson
, P. H.
2002, “Experimental Investigation of Streaky Structures in a Relaminarizing Boundary Layer
,” J. Turbul.
1468-5248, 3
, pp. 18
–30
.Copyright © 2007
by American Society of Mechanical Engineers
You do not currently have access to this content.
