Reynolds number effect on turbulent secondary flow in a duct

Kim, Myeongkyun; You, Donghyun

doi:10.1007/s12206-013-1161-0

Cited by 6 publications

(3 citation statements)

References 13 publications

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“…In this case, the sign of the quasilongitudinal vortices in the wall region predominantly coincides with the sign of . In [31], where LES calculations were performed for three Reynolds numbers, (…”

Section: Secondary Flows In Pipes Of Different Cross-sectionsmentioning

confidence: 99%

Prandtl’s Secondary Flows of the Second Kind. Problems of Description, Prediction, and Simulation

2021

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Abstract— The occurrence of turbulent pulsations in straight pipes of noncircular cross-section leads to the situation, when the average velocity field includes not only the longitudinal component but also transverse components that form a secondary flow. This hydrodynamic phenomenon discovered at the twenties of the last century (J. Nikuradse, L. Prandtl) has been the object of active research to the present day. The intensity of the turbulent secondary flows is not high; usually, it is not greater than 2–3% of the characteristic flow velocity. Nevertheless, their contribution to the processes of transverse transfer of momentum and heat is comparable to that of turbulent pulsations. In this paper, a review of experimental, theoretical, and numerical studies of secondary flows in straight pipes and channels is given. Emphasis is placed on the issues of revealing the physical mechanisms of secondary flow formation and developing the models of the apriori assessment of their forms. The specific features of the secondary flow development in open channels and channels with inhomogeneously rough walls are touched upon. The approaches of semiempirical simulation of turbulent flows in the presence of secondary flows are discussed.

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Section: Secondary Flows In Pipes Of Different Cross-sectionsmentioning

confidence: 99%

Prandtl’s Secondary Flows of the Second Kind. Problems of Description, Prediction, and Simulation

2021

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“…Huser and Biringen (1993), Huser et al (1994) and Zhu et al (2009) Lo and Lin (2006), Hsu et al (2011Hsu et al ( , 2012 and Kim and You (2014) P 900 Raiesi et al (2011) Heat transfer by Zhu et al (2010) Heat transfer by Rokni and Gatski (2001) With particles by Fairweather and Yao (2008) With particles by Adams et al (2011) turbulent scales. Moreover, the domain in the periodic direction, L x , must be long enough, keeping an adequate mesh resolution, Dx, to ensure that numerical solution is not affected.…”

Section: %600mentioning

confidence: 99%

Direct numerical simulation of a fully developed turbulent square duct flow up to Reτ=1200

Zhang

Trias

Gorobets

et al. 2015

International Journal of Heat and Fluid Flow

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a b s t r a c tVarious fundamental studies based on a turbulent duct flow have gained popularity including heat transfer, magnetohydrodynamics as well as particle-laden transportation. An accurate prediction on the turbulent flow field is critical for these researches. However, the database of the mean flow and turbulence statistics is fairly insufficient due to the enormous cost of numerical simulation at high Reynolds number. This paper aims at providing available information by conducting several Direct Numerical Simulations (DNS) on turbulent duct flows at Re s ¼ 300; 600; 900 and 1200. A quantitative comparison between current and previous DNS results was performed where a good agreement was achieved at Re s ¼ 300. However, further comparisons of the present results with the previous DNS results at Re s ¼ 600 obtained with much coarser meshes revealed some discrepancies which can be explained by the insufficient mesh resolution. At last, the mean flow and turbulent statistics at higher Re s was presented and the effect of Re s on the mean flow and flow dynamics was discussed.

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“…Curved rectangular cooling channels have two types of secondary flows, namely, the secondary flow of Prandtl's first and second kinds. The secondary flow of Prandtl's first kind is caused by the radial pressure gradient in curved sections, whereas the secondary motion of Prandtl's second kind is due to Reynolds stress and appears in straight noncircular ducts [22][23][24][25][26][27]. The Spalart-Allmaras (SA), linear k − ϵ, and linear k − ω turbulence models cannot describe the secondary motion of Prandtl's second kind because these turbulence models predict the normal Reynolds stress inaccurately [28].…”

Section: Introductionmentioning

confidence: 99%

Coupled Heat Transfer of Supercritical n-Decane in a Curved Cooling Channel

Liang

Liu

Pan

2016

Journal of Thermophysics and Heat Transfer

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The coupled heat transfer of supercritical-pressure n-decane in a concave heated, 90 deg bend, square channel was investigated numerically. Both the geometry and boundary conditions were close to those expected in active-cooled scramjet engines. The effect of secondary motions and wall thermal conductivity on heat transfer was studied. The flowfields obtained by the Spalart-Allmaras model and Reynolds stress model were compared. The secondary flow of Prandtl's first kind caused by the crosswise pressure gradient in the curved section was 1.0% of the maximum axial velocity. The secondary flow of Prandtl's second kind caused by Reynolds stress was one magnitude less than that of Prandtl's first kind. The Spalart-Allmaras turbulence model produced reasonable results with less computational effort than the Reynolds stress model. Secondary flow improves heat transfer by enhancing the mixing of the fluid. Furthermore, higher wall thermal conductivity produces more uniformly distributed temperature and heat flux. Nomenclature c p = specific heat at constant pressure, J · kg −1 K −1 D h = hydraulic diameter of cooling channel, m G = mass flux, kg · m −2 s −1 k w = wall thermal conductivity, W·m −1 K −1 P = pressure, Pa R = radii of curved channel, m q w = heat flux, W·m −2 T = temperature, K u x , u y = x, y velocity component of secondary flow, ms −1 u z = axial velocity, m·s −1 u z0 = axial velocity at centerline of channel, m·s −1 ρ = density, kg · m −3

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Reynolds number effect on turbulent secondary flow in a duct

Cited by 6 publications

References 13 publications

Prandtl’s Secondary Flows of the Second Kind. Problems of Description, Prediction, and Simulation

Prandtl’s Secondary Flows of the Second Kind. Problems of Description, Prediction, and Simulation

Direct numerical simulation of a fully developed turbulent square duct flow up to Reτ=1200

Coupled Heat Transfer of Supercritical n-Decane in a Curved Cooling Channel

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