Vorticity and turbulence production in pattern recognized turbulent flow structures

1977 ◽  
Vol 20 (10) ◽  
pp. S225 ◽  
Author(s):  
Helmut Eckelmann ◽  
Stavros G. Nychas ◽  
Robert S. Brodkey ◽  
James M. Wallace
Keyword(s):  
Turbulent Flow ◽  
Flow Structures ◽  
Turbulence Production

Directional Surface Roughness Influence on Turbulent Flow Structure

2019 ◽  
Author(s):  
Zambri Harun ◽  
Ashraf A. Abbas ◽  
Bagus Nugroho
Keyword(s):  
Surface Roughness ◽  
Turbulent Flow ◽  
Surface Pattern ◽  
Flow Structures ◽  
Mean Velocity ◽  
Turbulent Flow Structure ◽  
Series Of Experiments ◽  
The Mean ◽  
Turbulence Production ◽  
Current Report

Abstract A series of experiments have been conducted to investigate turbulent flow structures when it is exposed to a highly directional riblet-type surfaces roughness (converging-diverging/herringbone pattern) at a relatively low Reynolds number (Reτ). These experiments show that even at a low Reτ, the surface pattern is able to modify the turbulent boundary layer. Over the diverging region, we observe a decrease in drag penalty, while over the converging region there is an increase of drag penalty, which is indicated by the shift in the mean velocity profiles. The surface roughness also influences the turbulence production, indicated by the elevated turbulence intensities profiles for both the converging and diverging regions. The result seems to deviate from early investigations that show an increase in turbulence intensities above the converging region and a lowered turbulence intensities above the diverging region. The discrepancy may be caused by the lower Reτ Ret in the current report. Other important statistics such as skewness and flatness are also reported.

FORCED CONVECTION BASED HEAT TRANSFER ANALYSIS OF SPHERICAL DIMPLE AND PROTRUSION SURFACE IN TURBULENT FLOW

2017 ◽  
Vol 41 (5) ◽  
pp. 771-786 ◽  
Author(s):  
Ashif Perwez ◽  
Shreyak Shende ◽  
Rakesh Kumar
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Friction Factor ◽  
Vortex Flow ◽  
Rectangular Channel ◽  
Heat Transfer Analysis ◽  
Flow Structures ◽  
Transfer Enhancement ◽  
Heat Transfer Augmentation ◽  
Thermal Boundary Conditions

An experimental and numerical investigation is performed to study the effect of dimple and protrusion geometry on the heat transfer enhancement and the friction factor of surfaces with dimples and protrusions subjected to turbulent flow. The parameters used to compare the spherical dimples and protrusions are Nusselt Number, friction factor, and flow pattern. These parameters are obtained for a Reynolds number of 10500-60900. The spherical dimple results showed the greater heat transfer, which is about 6.97% higher and pressure loss which is 5.07% lower than the spherical protrusion. The realistic heat transfer augmentation capabilities of channels with dimples and protrusions can be studied from the experimental results. The comparison is made with respect to the smooth rectangular channel under the same flow and thermal boundary conditions. The numerical analysis is performed which shows the different vortex flow structures of the spherical dimples and protrusions channel.

Phenomenological investigations on the turbulent flow structures in a rod bundle array with mixing devices

2008 ◽  
Vol 238 (3) ◽  
pp. 600-609 ◽  
Author(s):  
Seok Kyu Chang ◽  
Sang Ki Moon ◽  
Won Pil Baek ◽  
Young Don Choi
Keyword(s):  
Turbulent Flow ◽  
Flow Structures ◽  
Rod Bundle

Numerical Study on the Turbulent Flow Structures of a Buoyant Pool Fire

2010 ◽  
Author(s):  
Sherman C. P. Cheung ◽  
Camby M. K. Se ◽  
G. H. Yeoh ◽  
Jiyuan Tu ◽  
Jane W. Z. Lu ◽  
...  
Keyword(s):  
Turbulent Flow ◽  
Numerical Study ◽  
Pool Fire ◽  
Flow Structures

scholarly journals EFFECTS OF HYDRAULIC PARAMETERS ON 3D TURBULENT FLOW STRUCTURES AROUND SUBMERGED SPUR-DIKES

2004 ◽  
Vol 48 ◽  
pp. 661-666
Author(s):  
Ichiro KIMURA ◽  
Takashi HOSODA ◽  
Sinichiro ONDA ◽  
Akihiro TOMINAGA
Keyword(s):  
Turbulent Flow ◽  
Flow Structures ◽  
Hydraulic Parameters ◽  
Spur Dikes
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