Boundary layers in planes of symmetry. I - Experiments in turbulent flow

Patel, V. C.; Baek, J. H.

doi:10.2514/3.9662

Cited by 17 publications

(7 citation statements)

References 4 publications

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“…Although lateral-straining studies were made earlier (e.g. of flow past a conical flare by Smits, Eaton & Bradshaw 1979, and a body of revolution at incidence by Patel & Baek 1987), those also included streamwise curvature, streamwise pressure gradients and/or mean three-dimensionality. Saddoughi & Joubert (1991) and Pompeo et al (1993) introduced a class of experiments with the advantage that they nominally contain one and only one extra strain at a time.…”

Section: Introductionmentioning

confidence: 99%

A numerical study of laterally strained wall-bounded turbulence

et al. 2009

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Direct numerical simulation (DNS) is used to study the effects of mean lateral divergence and convergence on wall-bounded turbulence, by applying uniform irrotational temporal deformations to a plane-channel domain. This extends a series of studies of similar deformations. Fast and slow straining fields are considered, leading to a matrix of four cases, all corresponding to zero-pressure-gradient (ZPG) flows along the centreplane in ducts with constant rectangular cross-sectional area but varying aspect ratio. The results are used to address basic physical and modelling questions, and create a database that allows detailed yet straightforward testing of turbulence models. Initial tests of three representative one-point models reveal meaningful differences. The extra-strain effects introduced by the matrix of fast and slow divergence and convergence are documented, separating the direct effects of the strain from the indirect ones that alter the shear rate and change the distance from the wall. Some findings are predictable, and none contradict experimental findings. Others require more thought, notably an asymmetry between the effect of convergence and divergence on the peak turbulence kinetic energy.

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Section: Introductionmentioning

confidence: 99%

A numerical study of laterally strained wall-bounded turbulence

et al. 2009

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“…27 " 30 Measurements in the plane of symmetry of the model combining a hemispherical nose with a hemispheroidal rear part were carried out by Patel and Baek. 31 These authors used their results in conjunction with a boundary-layer calculation employing the Cebeci-Smith turbulence model to study the effect of outer flow convergence or divergence on development of the boundary layer. 30 The theoretical prediction of this flow was improved by Sohn et al 32 by introducing a modified (k, £) turbulence model in the boundary-layer code.…”

Section: Cpmentioning

confidence: 99%

Experimental study of three-dimensional separation on a large-scale model

Barberis

Molton

1995

AIAA Journal

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Three-dimensional separation was studied by analyzing the flow past a large-scale model consisting of a halfprolate ellipsoid extended by a circular cylinder ending in a flat base at 45 deg with respect to the cylinder axis. The flow past the model, including boundary layer and vortical structures, was investigated in great detail using a three-component laser Doppler velocimetry system and three-hole pressure probes actuated by a displacement system installed inside the model. This last device allowed probing of the separating three-dimensional boundary layer very close to the surface. We observed how the boundary layer evolved as it gradually sheared into a vortex roll-up and then into an organized vortex. When skewing of the boundary layer increased, the difference in direction between the velocity gradient vector and the shear stress vector also increased. For this type of flow, turbulence models based on the assumption of isotropic turbulent viscosity are inadequate for numerical analysis. NomenclatureCp = static pressure coefficient L = model length Re = Reynolds number, (V Q L/v) V 1 = velocity components Vg = velocity components on the edge of the boundary layer Vq = upstream velocity at infinity X 1 = coordinates of a point on the surface a = angle of attack of the model v -kinematic viscosity (p = circumferential angle Subscripts i = 1 and 2 = components located in a plane parallel to the surface i = 3 = component normal to the surface

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“…A set of turbulent flow measurements on windward and leeward planes of symmetry was recently reported by Patel and Baek. 31 The authors made subsonic turbulent flow measurements for an axisymmetric body at 15-deg incidence. Their "measured" normalized eddy viscosity on the leeside plane of symmetry was markedly smaller than the Clauser constant 0.0168.…”

Section: Modification Of Algebraic Turbulence Model For Bodies At Incmentioning

confidence: 99%

“…Presented as Paper 89-0669 at the AIAA 27th Aerospace Sciences Meeting, Reno, NV, Jan. 1989; received Aug. 14,1989; revision received Aug. 15,1990; accepted for publication Aug. 31,1990 …”

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confidence: 99%

Simple turbulence models for supersonic flows - Bodies at incidence and compression corners

Shirazi

Truman

1991

AIAA Journal

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Parabolized Navier-Stokes (PNS) predictions of turbulent flows at supersonic and hypersonic speeds past two sphere-cones and a cone-cylinder-flare are used to evaluate simple turbulence models. Modifications to an algebraic turbulence model are proposed to improve predictions for flow on bodies at incidence. Predictions using a simple modification for the length scale and a model based upon Bradshaw's extra-strain-rate hypothesis are compared with measurements of supersonic and hypersonic flows. The modifications lead to significant improvements in predicted wall shear stress for a Mach 3 flow over a sphere-cone at moderate angle of attack. In addition, predictions of hypersonic flow past a cone-cylinder-flare are used to compare the algebraic CebeciSmith turbulence model with the nonequilibrium Johnson-King half-equation model. Predictions are compared with measurements of surface pressure and heat transfer for isothermal-wall flow at Mach 9.22 for a cone-cylinder-flare. The algebraic model predictions are quite satisfactory and no significant improvement is achieved with the nonequilibrium model for this flow with no streamwise separation.z a ,w Nomenclature = freestream speed of sound = empirical constants in the van Driest damping, Eqs. (4) and (17) = van Driest damping, Eqs. (4) and (17) = dimensionless effective conductivity, K e /K x , Eq. (2) = characteristic or reference length = freestream Mach number, V = dimensionless normal distance from wall, = dimensionless wall coordinate, Eq. (5) = dimensionless pressure, p/p^Vl, = Prandtl number = radial distance from body axis, Eq. (8) = freestream Reynolds number, p^V^L/jl= Stanton number based on freestream conditions, Eq. (25) = temperature = dimensionless velocity components in the Cartesian coordinates (x,y,z), N/L = dimensionless velocity tangent to the surface (excluding crossflow), U/V= dimensionless total velocity, (u 2 + v 2 + w 2 ) 1/2 = dimensionless velocity tangent to the surface (including crossflow), V T /V= freestream total velocity = dimensionless crossflow velocity, W/V= dimensionless physical Cartesian coordinates, x/L,y/L,z/L = angle of attack = Klebanoff intermittency factor, Eq. (9) . Member AIAA. tAssociate Professor, Department of Mechanical Engineering. Senior Member AIAA.d* = dimensionless kinematic, or "incompressible," displacement thickness, Eq. (7) 6 C = cone half-angle K = von Karman constant JM, = dimensionless coefficient of viscosity, \L/\L™ Ht = dimensionless eddy viscosity, /1,/jIoo He = dimensionless effective viscosity, £ e //Ioo, Eq. (1) £,i7,f = dimensionless computational coordinates in the streamwise (axial), radial (normal), and circumferential directions p = dimensionless density, p/pT -dimensionless total Reynolds shear stress (divided by density), Eq. (16) T W = dimensionless wall shear stress, r^/^^V^/L) 4> = meridian angle, 0 = 0 deg windward, 0= 180 deg leeward Subscripts and Superscripts oo = freestream e = edge of boundary layer eq = equilibrium value m = location of maximum in r ti = inner region of turbulent...

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Boundary layers in planes of symmetry. I - Experiments in turbulent flow

Cited by 17 publications

References 4 publications

A numerical study of laterally strained wall-bounded turbulence

A numerical study of laterally strained wall-bounded turbulence

Experimental study of three-dimensional separation on a large-scale model

Simple turbulence models for supersonic flows - Bodies at incidence and compression corners

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