Turbulent Transfer of Momentum and Heat in a Separated and Reattached Flow over a Blunt Flat Plate

1980 ◽  
Vol 102 (4) ◽  
pp. 749-754 ◽  
Author(s):  
Terukazu Ota ◽  
Nobuhiko Kon
Keyword(s):  
Heat Flux ◽  
Shear Stress ◽  
Flat Plate ◽  
Finite Thickness ◽  
Leading Edge ◽  
Turbulent Heat Flux ◽  
Turbulent Shear ◽  
Turbulent Heat ◽  
Turbulent Shear Stress ◽  
Separated And Reattached Flow

Turbulent shear stress and heat flux were measured with a hot-wire anemometer in the separated, reattached, and redeveloped regions of a two-dimensional incompressible air flow over a flat plate of finite thickness having blunt leading edge. The characteristic features of the turbulent heat flux are found to be nearly equal to those of the turbulent shear stress in the separated and reattached flow regions. However, in the turbulent boundary layer downstream from the reattachment point, the development of turbulent heat flux appears to be much quicker than that of turbulent shear stress. Eddy diffusivities of momentum and heat are evaluated and then the turbulent Prandtl number is estimated in the thermal layer downstream of reattachment. These results are compared with the available previous data.

Turbulence Measurements in a Separated and Reattached Flow Over a Blunt Flat Plate

1978 ◽  
Vol 100 (2) ◽  
pp. 224-228 ◽  
Author(s):  
Terukazu Ota ◽  
Masashi Narita
Keyword(s):  
Kinetic Energy ◽  
Flat Plate ◽  
Turbulent Kinetic Energy ◽  
Finite Thickness ◽  
Leading Edge ◽  
Turbulent Shear ◽  
Turbulence Measurements ◽  
Turbulent Shear Stress ◽  
Separated And Reattached Flow ◽  
Blunt Leading Edge

Turbulence measurements were made in the separated, reattached, and redeveloped regions of a two-dimensional incompressible air flow over a flat plate with finite thickness and blunt leading edge. In the boundary layer downstream of the reattachment point, Prandtl’s mixing length and turbulent kinetic energy length scale are estimated, and the correlation between the turbulent shear stress and the turbulent kinetic energy is described.

Heat Flux Measurements in Homogeneous Curved Shear Flow

1999 ◽  
Vol 121 (1) ◽  
pp. 190-194 ◽  
Author(s):  
A. G. L. Holloway ◽  
S. A. Ebrahimi-Sabet
Keyword(s):  
Heat Flux ◽  
Shear Flow ◽  
Turbulent Heat Flux ◽  
Heat Fluxes ◽  
Turbulent Shear ◽  
Turbulent Heat ◽  
Curvature Effects ◽  
Turbulent Shear Stress ◽  
Uniform Shear ◽  
Flow Curvature

Turbulent heat fluxes were measured far downstream of a fine heating wire stretched spanwise across a curved, uniform shear flow. The turbulence was approximately homogeneous and the overheat small enough to be passive. Strong destabilizing and stabilizing curvature effects were produced by directing the shear toward the center of curvature and away from the center of curvature, respectively. The dimensionless turbulent shear stress was strongly affected by the flow curvature, but the dimensionless components of the turbulent heat flux were found to be relatively insensitive.

Turbulence Measurements in an Axisymmetric Separated and Reattached Flow Over a Longitudinal Blunt Circular Cylinder

1980 ◽  
Vol 47 (1) ◽  
pp. 1-6 ◽  
Author(s):  
T. Ota ◽  
H. Motegi
Keyword(s):  
Shear Stress ◽  
Kinetic Energy ◽  
Circular Cylinder ◽  
Turbulent Kinetic Energy ◽  
Leading Edge ◽  
Turbulent Shear ◽  
Turbulence Measurements ◽  
Turbulent Shear Stress ◽  
Separated And Reattached Flow ◽  
Blunt Leading Edge

Turbulence measurements were made in the separated, reattached, and redeveloped regions of an axisymmetric incompressible airflow over a longitudinal circular cylinder with blunt leading edge. Three components of turbulent fluctuating velocity and the turbulent shear stress are presented. In the boundary layer downstream of the reattachment point, Prandtl’s mixing length and turbulent kinetic energy length scale are estimated, and the correlation between the turbulent shear stress and the turbulent kinetic energy is described.

Effects of an Upstream Circular Manipulator on the Flow Past a Cylinder-Flat Plate Junction

2003 ◽  
Author(s):  
Alan Dow ◽  
George Elizarraras ◽  
Hamid R. Rahai ◽  
Hamid Hefazi
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Flat Plate ◽  
Horseshoe Vortex ◽  
Turbulent Shear ◽  
Plate Surface ◽  
Mean Velocity ◽  
Time Resolved ◽  
Turbulent Shear Stress ◽  
Flow Past A Cylinder

Measurements of three components of mean velocity and simultaneous time-resolved measurements of axial and vertical turbulent velocities and their cross moment were made at three perpendicular planes slightly upstream of the corner and in the downstream interaction region of a cylinder-flat plate junction with and without an upstream circular manipulator. The circular manipulator was a smooth circular cylinder of 1.25 mm diameter, which was placed upstream of the cylinder at X/D = 1.2, within the boundary layer above the flat plate surface. Results show that when the manipulator is in place, there is a decrease in the axial mean velocity and increases in the axial mean squared turbulent velocity and turbulent shear stress at the first plane. There is an expanded region of secondary flow with reduced circulation, indicating that the manipulator has reduced the strength of the horseshoe vortex in this region.

scholarly journals Assessment of Turbulence Models in a Hypersonic Cold-Wall Turbulent Boundary Layer

Fluids ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 37 ◽  
Author(s):  
Junji Huang ◽  
Jorge-Valentino Bretzke ◽  
Lian Duan
Keyword(s):  
Boundary Layer ◽  
Heat Flux ◽  
Shear Stress ◽  
Turbulent Boundary Layer ◽  
Prandtl Number ◽  
Eddy Viscosity ◽  
Turbulence Models ◽  
Turbulent Heat Flux ◽  
Turbulent Heat ◽  
Cold Wall

In this study, the ability of standard one- or two-equation turbulence models to predict mean and turbulence profiles, the Reynolds stress, and the turbulent heat flux in hypersonic cold-wall boundary-layer applications is investigated. The turbulence models under investigation include the one-equation model of Spalart–Allmaras, the baseline k - ω model by Menter, as well as the shear-stress transport k - ω model by Menter. Reynolds-Averaged Navier-Stokes (RANS) simulations with the different turbulence models are conducted for a flat-plate, zero-pressure-gradient turbulent boundary layer with a nominal free-stream Mach number of 8 and wall-to-recovery temperature ratio of 0.48 , and the RANS results are compared with those of direct numerical simulations (DNS) under similar conditions. The study shows that the selected eddy-viscosity turbulence models, in combination with a constant Prandtl number model for turbulent heat flux, give good predictions of the skin friction, wall heat flux, and boundary-layer mean profiles. The Boussinesq assumption leads to essentially correct predictions of the Reynolds shear stress, but gives wrong predictions of the Reynolds normal stresses. The constant Prandtl number model gives an adequate prediction of the normal turbulent heat flux, while it fails to predict transverse turbulent heat fluxes. The discrepancy in model predictions among the three eddy-viscosity models under investigation is small.

Velocity, Temperature, and Turbulence Measurements in Air for Pipe Flow With Combined Free and Forced Convection

1973 ◽  
Vol 95 (4) ◽  
pp. 445-452 ◽  
Author(s):  
A. D. Carr ◽  
M. A. Connor ◽  
H. O. Buhr
Keyword(s):  
Heat Flux ◽  
Shear Stress ◽  
Reynolds Numbers ◽  
Viscous Sublayer ◽  
Constant Heat Flux ◽  
Experimental Results ◽  
Turbulent Shear ◽  
Low Reynolds Numbers ◽  
Turbulent Shear Stress ◽  
Free And Forced Convection

Experimental results are presented for velocity and temperature profiles and for the turbulence quantities vz′ t′ and vzt, for up-flow of air in a vertical pipe with constant heat flux at Reynolds numbers of 5000 to 14,000. The measurements show that, with increasing heat flux, superimposed free convection effects cause marked distortion of the flow structure at low Reynolds numbers, with the velocity maximum moving from the tube center to a position near the wall. The axial turbulence intensity, vz′, is depressed by increasing heat flux while the temperature intensity, t′, first decreases and then rises, with a shift in the position of the peak intensity away from the wall. On the basis of an analysis developed for heated turbulent flow, the turbulent shear stress and heat flux distributions are calculated from the experimental results. As the flow field becomes appreciably distorted on heating, it is found that the turbulent shear stress becomes very small, while the heat flux distribution suggests an increase in the width of the viscous sublayer.

A Separated and Reattached Flow on a Blunt Flat Plate

1976 ◽  
Vol 98 (1) ◽  
pp. 79-84 ◽  
Author(s):  
Terukazu Ota ◽  
Masaaki Itasaka
Keyword(s):  
Flat Plate ◽  
Finite Thickness ◽  
Flow Characteristics ◽  
Leading Edge ◽  
Reattachment Length ◽  
Reattachment Point ◽  
Separated And Reattached Flow ◽  
Velocity Pressure ◽  
Blunt Leading Edge ◽  
Made In

Velocity, pressure, and turbulence measurements were made in the separated, reattached, and redeveloped regions of a two-dimensional incompressible flow over a flat plate with finite thickness and blunt leading edge. Flow characteristics, such as the reattachment length and the flow pattern in the separated region, were determined. The boundary layer characteristics of the flow downstream of the reattachment point are presented through various experimental results.

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