Direct Numerical Simulation of Thermal Turbulent Boundary Layer Flow over Multiple V-Shaped Ribs at Different Angles

Direct numerical simulations (DNSs) of spatially developing thermal turbulent boundary layers over angle-ribbed walls were performed. Four rib angles (γ=90°,60°,45° and 30°) were examined. It was found that the 45° ribs produced the highest drag coefficient, whereas the 30° ribs most improved the St...

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Bibliographic Details
Published inEnergies (Basel) Vol. 16; no. 9; p. 3831
Main Authors Ji, Feng, Ding, Jing, Lu, Jianfeng, Wang, Weilong
Format Journal Article
LanguageEnglish
Published Basel MDPI AG 29.04.2023
Subjects
Boundary layer flow
Boundary layers
Computer industry
Decomposition
Direct numerical simulation
Dispersion
Drag coefficients
Friction
Heat flux
Heat transfer
Influence
Investigations
Mathematical models
Numerical analysis
Reynolds analogy
Reynolds number
ribbed surface
Secondary flow
Simulation
Simulation methods
Stanton number
Thermal boundary layer
Thermal simulation
thermal turbulent boundary layer
Turbulence
Turbulent boundary layer
Turbulent flow
Velocity
Vortices
United States
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Summary:Direct numerical simulations (DNSs) of spatially developing thermal turbulent boundary layers over angle-ribbed walls were performed. Four rib angles (γ=90°,60°,45° and 30°) were examined. It was found that the 45° ribs produced the highest drag coefficient, whereas the 30° ribs most improved the Stanton number. In comparison to the transverse rib case, streamwise velocity and dimensionless temperature in the V-shaped cases significantly increased in the near wall region and were attenuated by secondary flows further away from the ribs, which suggested a break of the outer-layer similarity in the scenario presented. The surprising improvement of heat transfer performance in the 30° rib case was mainly due to its large dispersive heat flux, while dispersive stress reached its peak value in the 45° case, emphasizing the dissimilarity in transporting momentum and heat by turbulence over a ribbed surface. Additionally, by calculating the global and local Reynolds analogy factors, we concluded that the enhancement in heat transfer efficiency was attributed to an increasing Reynolds analogy factor in the intermediate region as the rib angle decreased.
ISSN:1996-1073
1996-1073
DOI:10.3390/en16093831