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.

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.

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.

An Axisymmetric Separated and Reattached Flow on a Longitudinal Blunt Circular Cylinder

1975 ◽  
Vol 42 (2) ◽  
pp. 311-315 ◽  
Author(s):  
T. Ota
Keyword(s):  
Circular Cylinder ◽  
Flow Pattern ◽  
Flow Characteristics ◽  
Leading Edge ◽  
Experimental Results ◽  
Reattachment Length ◽  
Low Speed ◽  
Separated And Reattached Flow ◽  
Blunt Leading Edge

Low-speed experiments are made for an axisymmetric separated, reattached, and redeveloped flow over a longitudinal circular cylinder with blunt leading edge. The flow characteristics such as the reattachment length and the flow pattern in the separated region are measured. The redevelopment of the flow downstream of reattachment is also investigated through various experimental results.

Calculation of axisymmetric jets and wakes with a three-equation model of turbulence

1978 ◽  
Vol 86 (4) ◽  
pp. 745-759 ◽  
Author(s):  
Sedat Biringen
Keyword(s):  
Shear Stress ◽  
Kinetic Energy ◽  
Equation Model ◽  
Hyperbolic Partial Differential Equations ◽  
Turbulent Shear ◽  
Length Scale ◽  
Mean Velocity ◽  
Turbulent Shear Stress ◽  
Air Stream ◽  
Explicit Finite Difference

The concept of diffusion by bulk convection formulated by Bradshaw is applied to the transport equations for the turbulent kinetic energy, turbulent shear stress and an integral length scale. The resulting set of hyperbolic partial differential equations is solved by an explicit finite-difference scheme for the cases of incompressible axisymmetric wakes and jets in a coflowing air stream. It is found that the profiles of mean velocity and shear stress are almost insensitive to the empirical input whereas the profiles of kinetic energy are very sensitive.

scholarly journals An Analytically Derived Shear Stress and Kinetic Energy Equation for One-Equation Modelling of Complex Turbulent Flows

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 576
Author(s):  
Ronald M. C. So
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Kinetic Energy ◽  
Turbulent Flows ◽  
Energy Equation ◽  
Body Force ◽  
Turbulent Shear ◽  
Turbulent Shear Stress ◽  
Body Forces ◽  
External Body

The Reynolds stress equations for two-dimensional and axisymmetric turbulent shear flows are simplified by invoking local equilibrium and boundary layer approximations in the near-wall region. These equations are made determinate by appropriately modelling the pressure–velocity correlation and dissipation rate terms and solved analytically to give a relation between the turbulent shear stress τρ and the kinetic energy of turbulence (k =q22). This is derived without external body force present. The result is identical to that proposed by Nevzgljadov in A Phenomenological Theory of Turbulence, who formulated it through phenomenological arguments based on atmospheric boundary layer measurements. The analytical approach is extended to treat turbulent flows with external body forces. A general relation τρ = a11 - AFRiFq22 is obtained for these flows, where FRiF is a function of the gradient Richardson number RiF, and a1 is found to depend on turbulence models and their assumed constants. One set of constants yields a1= 0.378, while another gives a1= 0.328. With no body force, F ≡ 1 and the relation reduces to the Nevzgljadov equation with a1 determined to be either 0.378 or 0.328, depending on model constants set assumed. The present study suggests that 0.328 is in line with Nevzgljadov's proposal. Thus, the present approach provides a theoretical base to evaluate the turbulent shear stress for flows with external body forces. The result is used to reduce the k–e model to a one-equation model that solves the k-equation, the shear stress and kinetic energy equation, and an e evaluated by assuming isotropic eddy viscosity behavior.

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