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  • Drag reduction of turbulent boundary layers by means of grooved surfaces Citation for published version (APA): Pulles, C. J. A. (1988). Drag reduction of turbulent boundary layers by means of grooved surfaces. Eindhoven: Technische Universiteit Eindhoven. https://doi.org/10.6100/IR280307

    DOI: 10.6100/IR280307

    Document status and date: Published: 01/01/1988

    Document Version: Publisher’s PDF, also known as Version of Record (includes final page, issue and volume numbers)

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    Download date: 26. Jan. 2020

    https://doi.org/10.6100/IR280307 https://doi.org/10.6100/IR280307 https://research.tue.nl/en/publications/drag-reduction-of-turbulent-boundary-layers-by-means-of-grooved-surfaces(7e6e9511-c676-40df-bcf6-a743f7008b30).html

  • DRAG REDUCTION

    OF

    TURBULENT BOUNDARY LAYERS

    BY MEANS OF GROOVED SURFACES

    C:J.A.PULLES

  • DRAG REDUCTION

    OF

    TURBULENT BOUNDARY LAYERS

    BY MEANS Oir GROOVED SURFACES

    Proefschrift

    ter verkrijging vim de graad van doctor aan de Technische Universiteit Eindhoven, op gezag

    I

    van de Rector Magnificus, prof. dr. F.N. Hooge, I

    voor een commissie aangewezen door het College van Dekanen i ~ het openbaar te verdedigen op

    vrijdag 4 maart 1988 te 16.00 uur

    door

    CORNELIS J~HANNES ADRIANUS PULLES

    geboren te Eindhoven

    I d k: Oissertatiedrukkerij Wibro. Helmond.

  • Dit proefschrift is goedgekeurd door de promotoren:

    Dr. ir. G. Ooms

    en Prof. dr. ir. G. Vossers

    Co-promotor: Dr. K. Krishna Prasad

    This research has been supported by the Nederlands Technology

    Foundation (STW) as part of the program of the Foundation for Fundamental Research on Matter (FOM)

  • Drag reductlon of turbulent boundary layers

    bv means of grooved surfaces.

    Contents

    List of symbols.

    Chapter 1 Introduetion.

    § 1 . 1 Historie review.

    § 1.2 Short deseription of smooth wall

    turbulent boundary layer.

    § 1.3 Strueture of this thesis.

    Chapter 2 Summary of existing ideas. theories and

    5

    7

    experiments. 9

    § 2.1 Survey of different means of obtaining

    drag reduetion. 9

    § 2.2 Ideas and theories eoneerning

    drag reduetion. 12

    § 2 . 3 Experimental results from literature

    eoneerning drag reduetion by means

    of mierogrooves. 23

    Chapter 3 Experimental setup. 29

    § 3.1 Water ehannel. 29

    § 3.2 Measurement system. 34

    § 3.3 Deseription of the roughness types. 37

    Chapter 4 Point measurements. 42

    § 4.1 Introduetion. 42

    § 4.2 Profiles. 43

    § 4.3 Detailed point measurements. 51

    § 4.4 Conelusions. 62

    Chapter 5 Hydrogen bubble visualisation. 63

    § 5.1 Introduetion. 63

    § 5.2 Deseription of the experimental set-up. 65

    § 5.3 Some tests of the method. 70

    § 5.4 Results of the automated visualisation

    experiment.

    § 5.5 Results of the visualisation with

    LDA measurements.

    § 5.6 Conelusions.

    Chapter 6 Drag measurements.

    iii

    75

    77

    89

    93

  • § 6.1 Survey of different methods of

    measuring drag.

    § 6 . 1.1 Indirect methods.

    § 6 . 1.2 Direct methods.

    § 6.2 Drag balance Delft.

    § 6.3 Design considerations of the

    drag balance.

    § 6 .4 Some additional design formula of

    the balance.

    § 6.5 Sensor.

    § 6.6 Measurements and results.

    Chapter 7 Discussion and suggestions for

    further research.

    Appendix A rhe method of Head applied to the

    water channel flow.

    Appendix B rhe accuracy of the spanwise correlation function.

    References.

    Summary.

    Samenva t Ung.

    Dankwoord.

    Curriculum vitae.

    iv

    93

    93

    97

    99

    99

    104

    110

    110

    115

    119

    121

    126

    131

    132

    133

    133

  • List of symbols.

    Roman symbols.

    A

    a

    B

    b

    Cf

    D

    H

    h

    k

    I!

    P

    P p

    U

    u

    u

    * u

    U .. v

    v

    v

    w x

    y

    * y z

    van Driest constant

    ratio between Reynolds shear stress

    and turbulent intensity

    constant in Spaldings formuia

    groove width

    friction coefficient

    pipe diameter

    shape factor of boundary layer 9/ó*

    groove height

    trigger level in burst detection procedure

    mixing length

    pressure

    pressure gradient parameter

    velocity component in the direction of the

    free stream direction.

    fluctuating part of U. U-U rms of U

    shear stress velocity ~ w

    free stream flow velocity

    velocity component at right angles with the

    surface

    fluctuating part of V. V-V rms of V

    spanwise velocity component

    distance from start of boundary layer

    vertical distance from surface

    viscous length v/u*

    spanwise distance

    Greek symbols.

    ó boundary layer thickness

    v

    [m]

    [m]

    [m]

    [mis]

    [mis]

    [mis]

    [mis]

    [mis]

    [mis]

    [mis]

    [mis]

    [mis]

    Cm] Cm] Cm] Cm]

    Cm]

  • 6* displacement thickness Cm]

    E- dissipation of turbulent energy [J/kg]

    Tl dynamic viscosi ty . [kg/m s]

    e momentum loss thickness Cm] K. von Karman's konstant 0.41

    À. low speed streak spacing Cm]

    kinematic 2 v viscosity [m /s]

    p density [kg/m3 ]

    T total shear stress [N/m2]

    Tl viscous shear stress [N/m2]

    Tt turbulent shear stress [N/m2]

    T wall shear stress [N/m2] w

    Superscripts

    (overbar) ave rage value . time or ensemble ave rage

    + quantity made dimensionless by wall variables TW' pand v

    vi

  • Chapter Introduction.

    § 1.1 Historie review.

    Time af ter time nature provides us withunexpected phenomena.

    Although very common, turbulence should be reckoned among them. It is

    surprising to observe how a smooth laminar flow through a pipe, sudden

    ly becomes chaotic. Osborne Reynolds [lB9S] was the first to investi-

    gate this phenomenon in some depth .

    During the years most schol ars used the obvious random nature of

    turbulence in order to f ind a sui table model. WeIl known is the

    reasoning of Kolmogorov [1941] which provides an estimate of the

    length and timescales involved. It rests heavily on the assumption of

    scale invariance of turbulence.

    During the last two decades it became clear that turbulence is

    not as random as a first glance would suggest. Patterns are detected

    in wall boundary layers, jetsand pipe flow [see eg Kunen 19B4]. And

    literature is filled with descriptions of "bursts", "horse-shoe vorti-

    ces", "low speed streaks" and other coherent structures, which were

    detected by experimenters. Some of those structures are also observed

    in other turbulent flows. like turbulent jets and free shear layers.

    'Still more recent is the application of mathematical ideas of

    strange at tractors and chaotic systems to turbulence [Eckmann 19B1 J. No unification with the former ideas is apparent yet.

    i Also noted was the easy way turbulence was modified. for

    instanee by suction o