0
Research Papers: Fundamental Issues and Canonical Flows

Effects of Freestream Turbulence on the Characteristics in the Boundary Layer Near the Transition Onset Location

[+] Author and Article Information
Norah Patten

e-mail: norah.patten@ul.ie

Trevor M. Young

Department of Mechanical,
Aeronautical and Biomedical Engineering,
University of Limerick,
Limerick, Ireland

1Corresponding author.

Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received January 9, 2012; final manuscript received March 6, 2013; published online May 17, 2013. Assoc. Editor: Michael G. Olsen.

J. Fluids Eng 135(7), 071203 (May 17, 2013) (9 pages) Paper No: FE-12-1005; doi: 10.1115/1.4023989 History: Received January 09, 2012; Revised March 06, 2013

Experimental data is presented for a flat plate test facility with augmented levels of freestream turbulence (FST). The turbulence decay downstream of two turbulence generating grids, in addition to the integral length scales, is provided and good comparison with established correlations is presented. Boundary layer measurements using a single normal hotwire probe were obtained at FST intensities of 7%, 6%, 5.5%, 1.55%, and 1.45%, and the results presented include the fifth and 95th percentile of the velocity fluctuations and the root mean squared (RMS) velocity profiles near the transition onset region. The transition onset Reynolds number for each of the turbulence levels considered is consistent with theoretical findings. In all cases analyzed, the maximum fifth and 95th percentile far exceeded the maximum RMS values, with the location of the maximum 95th percentile closer to the wall compared to the maximum fifth percentile. Using probability density function (PDF) analysis, it is demonstrated that there is a dominating positive velocity fluctuation in the near-wall region and a dominating negative velocity fluctuation further out in the boundary layer and that the fluctuations in the boundary layer are greater compared to the freestream. The effect of the FST on the boundary layer is discussed with comparison to the Blasius solution and the influence of the fluctuations on the deviation from the Blasius profile is presented and discussed. Through investigation of the energy spectrum of the fluctuating velocity component within the boundary layer, it is shown that there is a higher energy content at lower frequency in the boundary layer when compared to that of the freestream.

FIGURES IN THIS ARTICLE
<>
Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.

References

Arnal, D., 1992, “Boundary Layer Transition: Prediction, Application to Drag Reduction,” AGARD Report No. 786. Special Course on Skin Friction Drag Reduction.
Reshotko, E., 1984, “Environment and Receptivity,” AGARD Report No. 709, Special Course on Stability and Transition of Laminar Flow.
Fransson, J., Matsubara, M., and Alfredsson, P., 2005, “Transition Induced by Freestream Turbulence,” J. Fluid Mech., 527, pp. 1–25. [CrossRef]
Filippov, V. M., 2002, “Influence of Plate Nose Heating on Boundary Layer Development,” J. Fluid Dyn., 37(1), pp. 27–36. [CrossRef]
Abu-Ghannam, B., and Shaw, R., 1980, “Natural Transition of Boundary Layers—The Effects of Turbulence, Pressure Gradient, and Flow History,” J. Mech. Eng. Sci., 22(5), pp. 213–228. [CrossRef]
Westin, K. J., Boiko, A. V., Klingmann, B. G., Kozlov, V. V., and Alfredsson, P. H., 1994, “Experiments in a Boundary Layer Subjected to Free Stream Turbulence. Part 1. Boundary Layer Structure and Receptivity,” J. Fluid Mech., 281, pp. 193–218. [CrossRef]
Saric, W., Reed, H., and Kerschen, E., 2002, “Boundary-Layer Receptivity to Freestream Disturbances,” Ann. Rev. Fluid Mech., 34, pp. 291–319. [CrossRef]
Matsubara, M., and Alfredsson, P., 2001, “Disturbance Growth in Boundary Layers Subjected to Freestream Turbulence,” J. Fluid Mech., 430, pp. 149–168. [CrossRef]
Kendall, J. M., 1985, “Experimental Study of Disturbances Produced in a Pre-Transitional Laminar Boundary Layer by Weak Freestream Turbulence,” AIAA Paper No. 85-1695.
Cossu, C., and Brandt, L., 2004, “On Tollmien-Schlichting-Like Waves in Streaky Boundary Layers,” Eur. J. Mech. B/Fluids, 23, pp. 815–833. [CrossRef]
Westin, J., 1997, “Laminar–Turbulent Boundary Layer Transition Influenced by Freestream Turbulence,” Ph.D. thesis, Department of Mechanics, KTH, Stockholm, Sweden.
Emmons, H. W., 1951, “The Laminar–Turbulent Transition in a Boundary Layer—Part 1,” J. Aeronaut. Sci., 18, pp. 490–498.
Griffin, P., and Davies, M., 2004, “Aerodynamic Entropy Generation Rate in a Boundary Layer With High Freestream Turbulence,” J. Fluid Eng., 126, pp. 700–703. [CrossRef]
Fransson, J., Brandt, L., Talamelli, A., and Cossu, C., 2004, “Experimental and Theoretical Investigation of the Non-Modal Growth of Steady Streaks in a Flat Plate Boundary Layer,” Phys. Fluids, 16, pp. 3627–3638. [CrossRef]
Hernon, D., Walsh, E. J., and McEligot, D. M., 2007, “Experimental Investigation into the Routes to Bypass Transition and Shear-Sheltering Phenomenon,” J. Fluid Mech., 591, pp. 461–479. [CrossRef]
Mathieu, J., and Scott, J., 2000, An Introduction to Turbulent Flow, Cambridge University Press, Cambridge, UK.
Boiko, A. V., Grek, G. R., Dovgal, A. V., and Koslov, V. V., 2002, The Origin of Turbulence in Near-Wall Flow, Springer, Berlin.
Morkovin, M. V., 1984, “Bypass Transition to Turbulence and Research Desiderata,” Transition in Turbines, Report No. NASA-CP-2386.
Roach, P. E., and Brierley, D. H., 1990, “The Influence of a Turbulent Free-Stream on Zero Pressure Gradient Transitional Boundary Layer Development, Part 1 Test Cases t3a and t3b,” ERCOFTAC Workshop, Lausanne, France.
Becker, S., Stoots, C. M., Condie, K. G., Dursk, F., and McEligot, D. M., 2002, “LDA-Measurements of Transitional Flows Induced by a Square Rib,” J. Fluid Eng., 124(1), pp. 108–118. [CrossRef]
Patten, N., Young, T. M., and Griffin, P., 2009, “Design and Characteristics of New Test Facility for Flat Plate Boundary Layer Research,” Proceedings of the ICFMTE, Venice, Italy, Oct. 28–30.
Chong, T., and Zhong, S., 2005, “On the Three-Dimensional Structure of Turbulent Spots,” ASME J. Turbomach, 127, pp. 545–551. [CrossRef]
Mayle, P. E., 1991, “The Role of Laminar-Turbulent Transition in Gas Turbine Engines,” ASME J. Turbomach., 113, pp. 509–537. [CrossRef]
Roach, P. E., 1987, “The Generation of Nearly Isotropic Turbulence by means of Grids,” Int. J Heat Fluid Flow, 8(2), pp. 82–92. [CrossRef]
Hinze, J. O., 1975, Turbulence, McGraw-Hill, New York.
Bruun, H. H., 1995, Hotwire Anemometry: Principles and Signal Analysis, Oxford University Press, New York.
Coleman, H. W., and Steel, W. G., 1989, Experimental and Uncertainty Analysis for Engineers, Wiley, New York.
Holman, J. P., 1997, Heat Transfer, 8th ed., McGraw-Hill, New York.
Sohn, K. H., O'Brien, J. E., and Reshotko, E., 1989, “Some Characteristics of Bypass Transition in a Heated Boundary Layer,” Report No. NASA TM 102126.
Jonas, P., Mazur, O., and Uruba, V., 2000, “On the Receptivity of the Bypass Transition to the Length Scale of the Outer Stream Turbulence,” Eur. J. Mech. B/Fluids, 19, pp. 707–722. [CrossRef]
Haykin, S., 1979, Nonlinear Methods of Spectral Analysis, Springer-Verlag, Berlin.
Jacobs, R., and Durbin, P., 2001, “Simulations of Bypass Transition,” J. Fluid Mech., 428, pp. 185–212. [CrossRef]

Figures

Grahic Jump Location
Fig. 2

Nondimensional velocity profiles compared to linear law of the wall (— linear law of the wall) for the same conditions as Fig. 1

Grahic Jump Location
Fig. 1

Comparison between experimental results and theoretical Blasius solution (o = Reθ 158, • = Reθ 249, x = Reθ 275, Δ = Reθ 291, + = Reθ 373, —Blasius solution)

Grahic Jump Location
Fig. 3

(a) Turbulence decay downstream of each grid compared to the Roach (1987) correlation. (— = 1.13(x/d)-5/7; - - - = 0.8(x/d)-5/7; + = SMR, Red = 1000; o = SMR, Red = 750; Δ = PP, Red = 2500; X = PP, Red = 1400. Red is the Reynolds number based on the thickness of the grid bar/wire). (b) Integral length scale growth downstream of the grids. (— = 0.2(x/d)0.5; + = Estimation using (Eq. (7)) for SMR, Red = 1000;  □= Estimation using (Eq. 7) for PP, Red = 1400; o Estimation using (Eq. (6)) for SMR, Red = 1000; X = Estimation using (Eq. (6)) for PP, Red = 1400).

Grahic Jump Location
Fig. 4

(a) Nondimensional velocity profiles compared to linear law of the wall (— linear law of the wall). (b) Normalized RMS velocity profiles where δ1 is the displacement thickness. (+ = Tu 7%, Reθ = 121; x = Tu 6%, Reθ = 145; o = Tu 5.5%, Reθ = 147; ◊ = Tu 5.2%, Reθ = 160; Δ = Tu 1.55%, Reθ = 304; • = Tu 1.45% Reθ = 323)

Grahic Jump Location
Fig. 5

Deviation in the velocity profiles due to the increase in FST compared to the Blasius profile. (+ = Tu 7%, Reθ = 121; x = Tu 6%, Reθ = 145; o = Tu 5.5%, Reθ = 147; ◊ = Tu 5.2%, Reθ = 160; Δ = Tu 1.55%, Reθ = 304; • = Tu 1.45% Reθ = 323; — Blasius profile).

Grahic Jump Location
Fig. 9

Spectral analysis (coresponding to traces provided in Fig. 8) at different freestream turbulence and at the same wall normal locations. (a) ▴: Tu = 7%, Reθ = 121. (b) •: Tu = 1.55%, Reθ = 304. Open symbols represent y/δ=0.5 and closed symbols represent y/δ=1.1.

Grahic Jump Location
Fig. 6

Probability Density Function (PDF) at near-wall, mid-boundary layer and boundary layer edge locations. (a) Tu = 7%, Reθ = 121, o = y/δ 0.28, x = y/δ 0.5, + = y/δ 1; (b) Tu = 6%, Reθ = 145, o = y/δ 0.25, x = y/δ 0.49, + = y/δ 1; (c) Tu = 5.5%, Reθ = 147, o = y/δ 0.27, x = y/δ 0.5, + = y/δ 1; and (d) Tu = 1.55%, Reθ = 304, o = y/δ 0.34, x = y/δ 0.5, + = y/δ 0.98.

Grahic Jump Location
Fig. 7

PDF analysis at different freestream turbulence and at the same wall normal locations. •: Tu = 1.55%, Reθ = 304; ▴: Tu = 7%, Reθ = 121; Open symbols represent y/δ=0.5 and closed symbols represent y/δ=1.1.

Grahic Jump Location
Fig. 8

Fifth percentile (average 5% negative velocity), 95th percentile (average 5% positive velocity) and RMS velocity components normalized with the freestream velocity upstream of transition onset. (a) Tu = 7%, Reθ 121; (b) Tu = 6%, Reθ = 145; (c) Tu 5.5%, Reθ = 147; and (d) Tu 1.55%, Reθ = 304. (▴ = 5th percentile; ▪ = 95th percentile; • = RMS).

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In