Turbulent boundary-layer flow from stationary to moving surfaces.

Tennant, J. S.; Yang, Tah-teh

doi:10.2514/3.6887

Cited by 13 publications

(4 citation statements)

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“…Using hot-wire anemometers , they were able to verify the theoretical model of equation ( 2 ) at least for the case of downstream moving walls. Tennant and his associates (Tennant [8]; Tennant and Yang [9]) also performed experiments with moving boundaries for both laminar and turbulent flow .…”

Section: Revi Ew Of Literature and Present Extensionsmentioning

confidence: 99%

Unsteady laminar separation: an experimental study

Koromilas

Telionis

1980

J. Fluid Mech.

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The design of most aerodynamic surfaces, as for example the helicopter rotor, is based essentially on quasi-steady theories. However, the dynamics of a rotating blade introduce unexpected fluctuations and overshoots of properties like lift, drag, etc. The phenomenon of unsteady stall is intimately connected with the development of an oscillating boundary layer and separation. Experimental investigation of such flows was undertaken by a method of visualization developed especially for the study of laminar or turbulent boundary layers and separation. The method captures the instantaneous two-dimensional flow field, including regions of separated flow, and provides accurate quantitative information. Laser-doppler anemometer measurements complement the optically obtained data. Results reveal that separation responds with time-lag to external disturbances, in agreement with unsteady stall data. Oscillating outer flows result in displacement of the point of separation and, under certain conditions, the Despard & Miller (1971) criterion was found to hold. Earlier theoretical models of separation are confirmed qualitatively and for the early stages of the transient phenomena. The findings provide physical insight and quantitative data that may help explain the phenomenon of unsteady stall and unsteady separation.

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Section: Revi Ew Of Literature and Present Extensionsmentioning

confidence: 99%

Unsteady laminar separation: an experimental study

Koromilas

Telionis

1980

J. Fluid Mech.

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“…Using hot-wire anemometers , they were able to verify the theoretical model of equation 2at least for the case of downstream moving walls. Tennant and his associates (Tennant [8]; Tennant and Yang [9]) also performed experiments with moving boundaries for both laminar and turbulent flow .…”

Section: ~~~~~~ -~~~7mentioning

confidence: 99%

Unsteady Laminar Separation--An Experimental Study.

Telionis¹,

Koromilas²

1978

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INTRODUCTION 1 CHAPTER 1. REVIEW OF LITERATURE AND PRESENT EXTENSIONS CHAPTER 2. STEADY FLOWS OVER MOVING WALLS 11 2.1 The Open Channel 2.2 Separation over Moving Walls CHAPTER 3. THE EXPERIMENTAL LAYOUT 3.1 The V.P.I. Water Tunnel 3.2 Optical Methods 3.3 The Models 38 3.4 Laser Doppler Velocimetry 3.5 Tunnel Calibration CHAPTER 4. TRANSIENT AND IMPULSIVE CHANGES OF THE PRESSURE DISTRIBUT ION 4.1 Impuls ive Changes R e lO~ Model A 4.2 Impulsive Change s R e = ~~~ 4.3 Impul sive Changes R e ~~ Model B 4.4 Mean Flow Accelerations 4.5 Separation over Model C , R e-~~ CHAPTER 5. PERIODIC DISTURBANCES OF THE OUTER FLOW

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“…However, experiments made in a subsonic diffuser with a partly moving surface [19] show that the influence of the discontinuity of the boundary conditions upstream is localized in a region whose length is of the order of the boundary-layer thickness.…”

Section: Numerical Solution Of the Boundary-layer Equations In The Prmentioning

confidence: 99%

Laminar boundary layer on a partly moving surface in the presence of blowing or suction

Gershbein¹,

Peigin²

1979

Fluid Dyn

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Planar and axisymmetric flows of a multicomponent compressible gas in a laminar boundary layer with nonzero tangential component of the velocity on a permeable surface are considered.The asymptotic solutions of the boundary-layer equations obtained earlier [1][2][3][4] for large values of the blowing and suction parameters are generalized to the case when the velocity vector of the blown or extracted gas makes an acute angle with th e surface of the body, this angle depending on the longitudinal coordinate. The region of applicability of the asymptotic formulas is estimated on the basis of the results of numerical solution of the boundary-layer equations.The results are given of some calculations of the boundary layer on a partly moving surface. ~any investigations have been made into the flow of liquids or gases in the boundary layer on amoving surface [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20].The solution of similarity boundary-layer equations was considered in [5L10] and of nonsimilarity equations in [11][12][13][14][15].In [16][17] the transition of a laminar boundary layer from a fixed section of the surface to a moving section was studied.The solution of the boundary~layer equations in the neighborhood of the velocity discontinuity point on the surface was constructed by an asymptotic method of outer and inner expansions.The problem of inclined blowing was considered in [20] in the framework of the equations of an inviscid boundary layer with a longitudinal pressure gradient that is determined in the process of solution.We also mention the experimental papers [18,19]. i. Asymptotic Solution of the Boundary-Layer Equations in the Case of Strong Inclined Blowin~We generalize the asymptotic solution of the laminar boundary-layer equations at large values of the blowing parameter ~ (see [I, 2]) to the case when the velocity vector of the blown gas makes an acute angle with the surface of the body. The notation is given in [1,2].At large values of the parameter $, the flow in the wall layer in the absence of chemical reactions is described by the system of equations (2.7) of [1] or (1.6) of [2], whose solution with the boundary conditions (1.1) has the form u~(x't) --nw(t~ pw(t) [P(t) J } +a.2(t), (i=l,... N), T(x,t) [ P(x) l~*(t' p(x,t)_[ P(x) 1~-'(') C,(x,t)=C,~(t) Tw(t) =[ P(t----)-J ' "9-~ I. P(t) JMoscow.

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Turbulent boundary-layer flow from stationary to moving surfaces.

Cited by 13 publications

References 1 publication

Unsteady laminar separation: an experimental study

Unsteady laminar separation: an experimental study

Unsteady Laminar Separation--An Experimental Study.

Laminar boundary layer on a partly moving surface in the presence of blowing or suction

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