Radial Distributions of Temporal-Mean Peripheral Velocity and Pressure for Fully Developed Turbulent Flow in Curved Channels

1960 ◽  
Vol 82 (3) ◽  
pp. 528-536 ◽  
Author(s):  
A. W. Marris
Keyword(s):  
Reynolds Number ◽  
Turbulent Flow ◽  
Rectangular Cross Section ◽  
Width Ratio ◽  
Curved Channels ◽  
Peripheral Velocity ◽  
Wide Range ◽  
Fully Developed Turbulent Flow ◽  
The Mean ◽  
Moving Fluid

Experimental results are presented for the radial distributions of pressure and peripheral velocity for the turbulent flow of water in two closed curved channels of rectangular cross section and large depth-to-width ratio. The traverses were taken at the equatorial section of the channel and sufficiently far around the curve for the effect of curvature on the mean motion to be fully established. The two channels employed had widely differing mean-radius-to-width ratios n. The data obtained for a wide range of flow rates in the channel with a larger n indicated that Reynolds similarity existed between the flows in this channel. These data are compared with the pressure and velocity profiles predicted by potential flow theory and with a semiempirical logarithmic velocity distribution. Results obtained for the channel with smaller n showed that at above a certain Reynolds number an anomaly occurred in the flow, manifesting itself as an unstable “belt” of faster moving fluid, which moved outward from the inner wall as the Reynolds number was increased. This effect, considered to be the consequence of upstream stall, was accompanied by an adverse longitudinal-pressure gradient at the inner wall of the channel. It appeared to be eliminated by the insertion of an upstream splitter vane.

An Analysis of Heat Transfer for Fully Developed Turbulent Flow in Concentric Annuli

1968 ◽  
Vol 90 (1) ◽  
pp. 43-50 ◽  
Author(s):  
N. W. Wilson ◽  
J. O. Medwell
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Turbulent Flow ◽  
Velocity Distribution ◽  
Maximum Velocity ◽  
Dimensionless Form ◽  
Temperature Distributions ◽  
Wide Range ◽  
Fully Developed Turbulent Flow ◽  
Heat And Momentum Transfer

The heat and momentum transfer analogy is employed to analyze the heat transfer phenomena for turbulent flow in concentric annuli. A modification of the velocity distribution due to Van Driest is assumed and equations in dimensionless form are developed to predict: (a) the position of maximum velocity in the annulus; (b) the friction factor-Reynolds number relationship, and (c) temperature distributions and heat transfer relations over a wide range of Reynolds number and Prandtl modulus.

ON FULLY DEVELOPED TURBULENT FLOW IN CURVED CHANNELS

1956 ◽  
Vol 34 (11) ◽  
pp. 1134-1146 ◽  
Author(s):  
A. W. Marris
Keyword(s):  
Experimental Data ◽  
Turbulent Flow ◽  
Velocity Distribution ◽  
Radius Of Curvature ◽  
Mixing Length ◽  
Mean Velocity ◽  
Curved Channels ◽  
Fully Developed Turbulent Flow ◽  
The Mean ◽  
Theoretical Results

Formulae for the radial distribution of velocity and vorticity for the case of fully developed turbulent flow in the channel between concentric and infinitely long cylinders are developed on a similarity vorticity transfer theory, by postulating an Eulerian mixing length function dependent on both position and radius of curvature. The theoretical results obtained for the mean velocity distribution across the channel compare satisfactorily with existing experimental data when the curvature dependent parameters are given appropriate numerical values.

Moderate Reynolds Number Mixing in a T-Channel

2010 ◽  
Author(s):  
Susan Thomas ◽  
Tim Ameel
Keyword(s):  
Reynolds Number ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Large Body ◽  
Experimental Studies ◽  
Numerical Work ◽  
Moderate Reynolds Number ◽  
Wide Range ◽  
Particle Imaging ◽  
Experimental Trials

An experimental investigation of water flow in a T-shaped channel with rectangular cross section (20 × 20 mm inlet ID and 20 × 40 mm outlet ID) has been conducted for a Reynolds number Re range of 56 to 422, based on inlet diameter. Dynamical conditions and the T-channel geometry of the current study are applicable to the microscale. This study supports a large body of numerical work, and resolution and the interrogation region are extended beyond previous experimental studies. Laser induced fluorescence (LIF) and particle imaging velocimetry (PIV) are used to characterize flow behaviors over the broad range of Re where realistic T-channels operate. Scalar structures previously unresolved in the literature are presented. Special attention is paid to the unsteady flow regimes that develop at moderate Re, which significantly impact mixing but are not yet well characterized or understood. An unsteady symmetric topology, which develops at higher Re and negatively impacts mixing, is presented, and mechanisms behind the wide range of mixing qualities predicted for this regime are explained. An optimal Re operating range is identified based on multiple experimental trials.

Optimal energy growth in stably stratified turbulent Couette flow

2021 ◽  
Author(s):  
Grigory Zasko ◽  
Andrey Glazunov ◽  
Evgeny Mortikov ◽  
Yuri Nechepurenko ◽  
Pavel Perezhogin
Keyword(s):  
Boundary Layer ◽  
Turbulent Flow ◽  
Couette Flow ◽  
Large Scale ◽  
Thin Layers ◽  
Plane Couette Flow ◽  
Turbulent Layer ◽  
Wide Range ◽  
The Mean ◽  
Optimal Disturbances

<p>In this report, we will try to explain the emergence of large-scale organized structures in stably stratified turbulent flows using optimal disturbances of the mean turbulent flow. These structures have been recently obtained in numerical simulations of turbulent stably stratified flows [1] (Ekman layer, LES) and [2] (plane Couette flow, DNS and LES) and indirectly confirmed by field measurements in the stable boundary layer of the atmosphere [1, 2]. In instantaneous temperature fields they manifest themselves as irregular inclined thin layers with large gradients (fronts), spaced from each other by distances comparable to the height of the entire turbulent layer, and separated by regions with weak stratification.</p><p>Optimal disturbances of a stably stratified turbulent plane Couette flow are investigated in a wide range of Reynolds and Richardson numbers. These disturbances were computed based on a simplified linearized system of equations in which turbulent Reynolds stresses and heat fluxes were approximated by isotropic viscosity and diffusion with coefficients obtained from DNS results. It was shown [3] that the spatial scales and configurations of the inclined structures extracted from DNS data coincide with the ones obtained from optimal disturbances of the mean turbulent flow.</p><p>Critical value of the stability parameter is found starting from which the optimal disturbances resemble inclined structures. The physical mechanisms that determine the evolution, energetics and spatial configuration of these optimal disturbances are discussed. The effects due to the presence of stable stratification are highlighted.</p><p>Numerical experiments with optimal disturbances were supported by the RSF (grant No. 17-71-20149). Direct numerical simulation of stratified turbulent Couette flow was supported by the RFBR (grant No. 20-05-00776).</p><p>References:</p><p>[1] P.P. Sullivan, J.C. Weil, E.G. Patton, H.J. Jonker, D.V. Mironov. Turbulent winds and temperature fronts in large-eddy simulations of the stable atmospheric boundary layer // J. Atmos. Sci., 2016, V. 73, P. 1815-1840.</p><p>[2] A.V. Glazunov, E.V. Mortikov, K.V. Barskov, E.V. Kadantsev, S.S. Zilitinkevich. Layered structure of stably stratified turbulent shear flows // Izv. Atmos. Ocean. Phys., 2019, V. 55, P. 312–323.</p><p>[3] G.V. Zasko, A.V. Glazunov, E.V. Mortikov, Yu.M. Nechepurenko. Large-scale structures in stratified turbulent Couette flow and optimal disturbances // Russ. J. Num. Anal. Math. Model., 2010, V. 35, P. 35–53.</p>

Turbulent Flow of Water in Plane Curved Channels of Finite Depth

1963 ◽  
Vol 85 (3) ◽  
pp. 377-390 ◽  
Author(s):  
O. G. Brown ◽  
A. W. Marris
Keyword(s):  
Experimental Study ◽  
Shear Flow ◽  
Turbulent Flow ◽  
Finite Depth ◽  
Width Ratio ◽  
Mean Flow ◽  
Curved Channel ◽  
Flow Acceleration ◽  
Curved Channels ◽  
Convex Wall

An experimental study of turbulent flow in a plane curved channel of depth-to-width ratio 8:1 and mean radius-to-width ratio 1.83:1 by means of measured distributions of mean peripheral velocity and pressure and flow visualization methods using dye. It appears that due to the large depth-to-width ratio, the secondary flow, though appreciable, is apparent mainly in the end plate regions. Even so it has a pronounced effect on the flow near the inner (convex) wall. It appears that the sharp curvature is effective in quenching the turbulence of the entering rectilinear shear flow at the inner wall of the curved channel by causing a mean flow acceleration in this region. The study indicates that localized backflows can occur at the inner wall at the meeting of secondary and main flows under near-laminar conditions.

Investigation of Fully Developed Turbulent Flow in a Straight Duct With Large Eddy Simulation

1994 ◽  
Vol 116 (4) ◽  
pp. 677-684 ◽  
Author(s):  
M. D. Su ◽  
R. Friedrich
Keyword(s):  
Reynolds Number ◽  
Large Eddy Simulation ◽  
Turbulent Flow ◽  
Secondary Flow ◽  
Initial Conditions ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Fully Developed Turbulent Flow ◽  
High Reynolds ◽  
Straight Duct

Large eddy simulations have been performed in straight ducts with square cross section at a global Reynolds number of 49,000 in order to predict the complicated mean and instantaneous flow involving turbulence-driven secondary motion. Isotropic grid systems were used with spatial resolutions of 256 * 642. The secondary flow not only turned out to develop extremely slowly from its initial conditions but also to require fairly high resolution. The obtained statistical results are compared with measurements. These results show that the large eddy simulation (LES) is a powerful approach to simulate the complex turbulence flow with high Reynolds number. Streaklines of fluid particles in the duct show the secondary flow clearly. The database obtained with LES is used to examine a statistical turbulence model and describe the turbulent vortex structure in the fully developed turbulent flow in a straight duct.

Turbulence Measurements in the Corner Wall Jet

2014 ◽  
Author(s):  
Barrett Poole ◽  
Joseph W. Hall
Keyword(s):  
Reynolds Number ◽  
Flow Field ◽  
Turbulent Flow ◽  
Three Dimensional ◽  
Wall Jet ◽  
Hot Wire ◽  
Turbulence Measurements ◽  
Vertical Growth ◽  
The Mean ◽  
Turbulent Flow Field

The corner wall jet is similar to the standard three-dimensional wall jet with the exception that one half of the surface has been rotated counter-clockwise by 90 degrees. The corner wall jet investigated here is formed using a long round pipe with a Reynolds number of 159,000. Contours of the mean and turbulent flow field were measured using hot-wire anemometry. The results indicate that the ratio of lateral to vertical growth in the corner wall jet is approximately half of that in a standard turbulent three-dimensional wall jet.

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