Turbulent structures and statistics in turbulent channel flow with two-dimensional slits

Makino, Soichiro; Iwamoto, Kaoru; Kawamura, Hiroshi

doi:10.1016/j.ijheatfluidflow.2008.03.010

Cited by 26 publications

(18 citation statements)

References 22 publications

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“…Accordingly, splattering effects are suggested to occur due to the reattachment. These trends are similarly observed in cases of periodic fences (8) and the backward step (11) , and the transport processes near the reattachment point are analogous in separated flows. …”

Section: Budgets Of Reynolds Stresssupporting

confidence: 57%

“…At the present time, it is not evident if the overall heat transfer in the case with an obstacle can actually exceed the flat-plate case. The recent DNSs (Direct Numerical Simulations) for non-periodic cases (8)- (10) did not resolve this question since they targeted on basic fluid mechanics not paying special attention to the heat transfer enhancement.…”

Section: Introductionmentioning

confidence: 99%

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Heat Transfer Characteristics and Reynolds Stress Budgets in Single-Rib Mounting Channel

Miura

Matsubara

Sakurai

2010

JTST

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Heat transfer and fluid flow in a single-rib mounting channel were investigated by directly solving Navier-Stokes and energy equations. Flow and thermal fields were considered to be fully developed at the inlet of the channel, and the simulation was made for spatial advancement of turbulent heat transfer. Keeping the frictional Reynolds number, Re τ0 , at 150, the rib height ratio was changed in four steps from H/δ = 0.05 to H/δ = 0.4. Computational results were confirmed to be nearly independent of grid meshes. In addition, numerical accuracy was confirmed through close agreement between computed mean pressure and the experiment by Yao et al. (1995). The numerical results revealed that the highest value of the mean Nusslet number was as large as 1.3 times the smooth surface consuming the same pumping power, and the local enhancement of heat transfer was correlated with the turbulence increase near the rib front and the reattachment point. According to the Reynolds stress budgets for H/δ = 0.2, there were mechanisms to induce powerful fluctuations: (1) Streamwise fluctuation was increased through production by flow deceleration in the upstream of the rib; (2) Redistribution to wall-normal and spanwise fluctuations was fortified by the fluid splattering to the rib front. Therefore, excellent performance of heat transfer was concluded to occur due to flow structures, which induce the strong disturbance near the rib front triggering smooth transition of the separated shear layer.

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Section: Budgets Of Reynolds Stresssupporting

confidence: 57%

Section: Introductionmentioning

confidence: 99%

Heat Transfer Characteristics and Reynolds Stress Budgets in Single-Rib Mounting Channel

Miura

Matsubara

Sakurai

2010

JTST

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“…By using the same obstruction as (Makino et al, 2008), the blockage ratio of the rectangular orifice is 1:2, i.e., the distance between the channel surface and the orifice edge is 0.5d. The computational domain volume is 12.8d Â 2d Â 6.4d in the streamwise, wall-normal, and spanwise directions, respectively.…”

Section: Numerical Proceduresmentioning

confidence: 99%

“…Makino et al (2008) carried out DNSs of the turbulent Newtonian-fluid flow in a channel with periodic twodimensional ribs, i.e., rectangular orifices. Khoury et al (2010) considered a similar problem but for a single thin-plate obstruction without periodic repeating.…”

Section: Introductionmentioning

confidence: 99%

DNS of viscoelastic turbulent channel flow with rectangular orifice at low Reynolds number

Tsukahara

Kawase

Kawaguchi

2011

International Journal of Heat and Fluid Flow

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“…They presented the budget for turbulent kinetic energy, and the production and turbulent-diffusion terms of the temperature variance only at the middle of the enclosure. Makino et al (8), (9) carried out DNS of turbulent heat transfer in a channel flow with periodic two-dimensional slits, and showed the budgets for the Reynolds stresses and the production terms of the turbulent heat fluxes. In a previous paper (10) , we performed DNS of turbulent heat transfer in a single-rib mounting channel and indicated that the rib improved momentum-and heat-transfer performance.…”

Section: Introductionmentioning

confidence: 99%

Turbulent-Heat-Flux and Temperature-Variance Budgets in a Single-Rib Mounting Channel

Miura

Matsubara

Sakurai

2012

JTST

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Heat transfer and fluid flow in a single-rib mounting channel were investigated by directly solving Navier-Stokes and energy equations. The flow and thermal fields were considered to be fully developed at the inlet of the channel, and the simulation was made for spatial advancement of turbulent heat transfer. The Reynolds number based on the friction velocity at the inlet and the channel half width was 150. The Prandtl number was 0.71. The budgets for turbulent heat fluxes and temperature variance at various sections were presented and were investigated, which would be useful for testing and developing turbulence models. Near a circular vortex in front of the rib, pressure diffusion terms made an important contribution. Remarkable production terms were generated near a reattachment point. Production and dissipation terms were not dominant in front of and above the rib, and a time scale ratio exceeded 2.0 in the region.

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Turbulent structures and statistics in turbulent channel flow with two-dimensional slits

Cited by 26 publications

References 22 publications

Heat Transfer Characteristics and Reynolds Stress Budgets in Single-Rib Mounting Channel

Heat Transfer Characteristics and Reynolds Stress Budgets in Single-Rib Mounting Channel

DNS of viscoelastic turbulent channel flow with rectangular orifice at low Reynolds number

Turbulent-Heat-Flux and Temperature-Variance Budgets in a Single-Rib Mounting Channel

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