Heat transfer in fully developed turbulent channel flow with streamwise traveling wave-like wall deformation

Uchino, Keisuke; Mamori, Hiroya; Fukagata, Koji

doi:10.1299/jtst.2017jtst0003

Cited by 13 publications

(4 citation statements)

References 22 publications

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“…As for the dissimilarity, many researchers have investigated it to achieve energy-efficient heat transfer by controlling the flow field, based on various control strategies (e.g. Hasegawa and Kasagi, 2011;Uchino, et al, 2017). In this context, our result suggests that the flow pulsation is one of the ways to achieve a dissimilar control of momentum transfer and heat transfer.…”

Section: Introductionmentioning

confidence: 71%

Effect of thermal wall condition on the dissimilarity of momentum and heat transfer in pulsating channel flow

Yamazaki

Oda

Matsumoto

et al. 2020

JTST

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Pulsating turbulent channel flows under constant temperature difference (CTD) condition and uniform heat flux heating (UHF) condition are studied by direct numerical simulation (DNS). The main objective of the present study is to clarify how the dissimilarity between momentum transfer and heat transfer appeared in the pulsating flows, in which the dissimilarity may originate from the CTD condition dissimilar to the no-slip condition of the velocity field rather than from the thermo-fluid physics under pulsation. Simulations have been performed for three pulsation frequencies under the friction Reynolds number at steady-state, Re s = 300. Comparing the phase-averaged quantities under CTD and UHF conditions, it is found that the frequency dependence of the temperature oscillations in the near-wall region is almost the same regardless of the thermal boundary condition although the time-averaged temperature profiles are different. As a result, the ratio of Stanton number to friction factor, which works as a barometer of the analogy, changes during the pulsation period at both CTD and UHF conditions. Besides, the oscillation amplitude becomes larger as the pulsation frequency increases. Therefore, it was confirmed that the dissimilarity appears regardless of the thermal boundary condition. In addition, turbulent Prandtl number shows similar cyclic behavior to the ratio of Stanton number to friction factor. Time variations of each component constituting turbulent Prandtl number reveal that increasing dissimilarity at the high frequency is mainly attributed to the amplified oscillation of velocity gradient near the wall, where Reynolds shear stress and turbulent heat flux are kept at around the time-averaged values because the near-wall vortex structures cannot follow the rapid change of flow rate.

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Section: Introductionmentioning

confidence: 71%

Effect of thermal wall condition on the dissimilarity of momentum and heat transfer in pulsating channel flow

Yamazaki

Oda

Matsumoto

et al. 2020

JTST

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“…Hasegawa & Kasagi 24 and Yamamoto et al 25 introduced suboptimal control theory and found that the dissimilar control works even in flows where the averaged energy and momentum transport equations have an identical form, and the optimal input mode exhibits a streamwise traveling-wave-like property. Successful dissimilar controls by traveling-wavelike input from the wall have been actually reported by some numerical studies using blowing/suction from the wall [26][27][28] or wall deformation 29 . The essential mechanism of such dissimilar transfer control is the different sensitivities of velocity and temperature fields to the control input from the wall, which results from the fact that velocity is a divergence-free vector quantity whereas temperature is a scalar 24 .…”

Section: Introductionmentioning

confidence: 79%

Spectral analysis on dissimilarity between turbulent momentum and heat transfers in plane Couette turbulence

Kawata,

Tsukahara

2022

Preprint

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Nonlinear interaction between different scales in turbulence results in both interscale and spatial transport of turbulent energy, and the role of such scale interactions in turbulent heat transfer mechanism is also of practical importance from the engineering viewpoint. In the present study, we investigate a turbulent plane Couette flow with passive-scalar heat transfer at the Prandtl number 0.71, in order to address the similarity/difference between the scale interactions in the velocity and temperature fields. The constant-temperature-difference boundary condition is used so that the mean velocity and temperature profiles are similar, and then the roles of interscale and spatial transports are compared for the spectral transport budgets of the turbulent energies and temperature-related statistics. We show that turbulent heat transfer occurs at relatively small streamwise length scales compared to momentum transfer, although molecular diffusion is more significant in the temperature field as the Prandtl number is less than 1. Detailed analysis on the transport budgets of the temperature-related spectra shows that scale interactions in temperature field supply more energy to small scales than those in velocity field. Such significant temperature cascade leads to more energetic temperature fluctuation at small scales, which eventually results in the dissimilarity between the spectra of turbulent heat and momentum transfers.

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“…In contrast to the passive control, active flow control techniques which require actuation power, are performed to increase the heat transfer in the fully developed turbulent channel flow. For example, the blowing and suction from the wall based on the suboptimal and optimal control theories (Kasagi et al, 2012;Hasegawa and Kasagi, 2011;Yamamoto et al, 2013) and the traveling wave-like blowing and suction or wall deformation (Higashi et al, 2011;Uchino et al, 2017;Kaithakkal et al, 2020). Recently, the traveling wave effect was investigated for the laminar channel flow (Kaithakkal et al, 2021) and for the turbulent Taylor-Couette flow (Mamori et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Heat transfer enhancement by feedback blowing and suction based on vortical structure in turbulent channel flow at low Reynolds number

Aoki

Mamori

Miyazaki

2022

JTST

Self Cite

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Heat transfer enhancement is essential in low Reynolds number flow because recent small heat exchangers require narrow flow passages. In the present study, we conducted direct numerical simulations of the channel flow to investigate the turbulence sustaining effect by feedback blowing and suction from the wall. The initial flow field corresponded to the fully developed turbulent channel flow, and the Reynolds number suddenly decreased at the beginning of the simulation. The results indicated that there are two approaches for the turbulence maintenance. If the amplitude of the blowing and suction is high, then the sensor detects the blowing and suction from the wall, and the velocity fluctuation corresponds to self-maintenance. Then, we obtained large heat transfer. However, the gain was small. If the amplitude is moderate, then the blowing from the wall to the low-speed streaky structures pushes up, and the suction attracts the high-speed streak toward the wall. The effect to increase the Reynolds shear stress and heat transfer results in the promotion of the turbulence and heat transfer with high gain.

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Heat transfer in fully developed turbulent channel flow with streamwise traveling wave-like wall deformation

Cited by 13 publications

References 22 publications

Effect of thermal wall condition on the dissimilarity of momentum and heat transfer in pulsating channel flow

Effect of thermal wall condition on the dissimilarity of momentum and heat transfer in pulsating channel flow

Spectral analysis on dissimilarity between turbulent momentum and heat transfers in plane Couette turbulence

Heat transfer enhancement by feedback blowing and suction based on vortical structure in turbulent channel flow at low Reynolds number

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