213 Numerical Simulation of Turbulent Separated Flow and Heat Transfer in a Symmetric Sudden Expansion Rectangular Channel

2006 ◽  
Vol 2006.41 (0) ◽  
pp. 77-78
Author(s):  
Kazuaki SUGAWARA ◽  
Hiroyuki YOSHIKAWA ◽  
Terukazu OTA
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Rectangular Channel ◽  
Separated Flow ◽  
Sudden Expansion ◽  
Flow And Heat Transfer ◽  
Turbulent Separated Flow

DNS of Three-Dimensional Unsteady Separated Flow and Heat Transfer in a Sudden-Expansion Channel

2005 ◽  
Author(s):  
Hiroyuki Yoshikawa ◽  
Kimitake Ishikawa ◽  
Terukazu Ota
Keyword(s):  
Heat Transfer ◽  
Rectangular Channel ◽  
Three Dimensional ◽  
Separated Flow ◽  
Expansion Ratio ◽  
Sudden Expansion ◽  
Number Range ◽  
Simulation Methodology ◽  
Flow And Heat Transfer ◽  
Unsteady Separated Flow

Numerical results of a three-dimensional unsteady separated flow and heat transfer in a sudden expansion rectangular channel are presented. A direct numerical simulation methodology was employed in the calculations using the finite difference method. Treated in the present study is a rectangular channel of aspect ratio AR = 4.0 and expansion ratio ER = 2.5 in a Reynolds number range from 200 to 1000. It is found that the flow becomes unsteady at Re = 400 and severely complicated at Re = 500 to 1000. The heat transfer characteristics are presented and discussed in relation to the flow ones.

Numerical Simulation of Nonlinear Flow and Heat Transfer in a Sudden Expansion and Contraction Channel

2016 ◽  
Author(s):  
M. Yang ◽  
L. Q. Yang ◽  
W. Lu ◽  
L. Li ◽  
Q. X. Liu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Reynolds Number ◽  
Rectangular Channel ◽  
Flow Region ◽  
Nonlinear Flow ◽  
Forced Flow ◽  
Sudden Expansion ◽  
Symmetric State ◽  
Flow And Heat Transfer

Numerical simulation of forced flow in sudden-expansion followed by sudden-contraction rectangular channel was presented for the whole flow region. The nonlinear flow and heat transfer characteristics were investigated by various Reynolds number and geometrical dimension and the critical Reynolds numbers under different conditions have been calculated. The results show flow and heat transfer from symmetric state to asymmetric state with the increase of Re. When Re<Rec (critical Reynolds number for flow transformation), the symmetric state is stable. On the other hand, when Re ≥Rec, the flow loses stability and from symmetric to asymmetric via a symmetry-breaking bifurcation. And the heat transfer performance have relevant characteristics as fluid flow.

DNS of Expansion Ratio Effects on Three-Dimensional Unsteady Separated Flow and Heat Transfer Around a Downward Step

2005 ◽  
Author(s):  
Aya Kito ◽  
Kazuaki Sugawara ◽  
Hiroyuki Yoshikawa ◽  
Terukazu Ota
Keyword(s):  
Heat Transfer ◽  
Rectangular Channel ◽  
Three Dimensional ◽  
Side Wall ◽  
Separated Flow ◽  
Flow Region ◽  
Expansion Ratio ◽  
Mean Velocity ◽  
Flow And Heat Transfer ◽  
Channel Expansion

The direct numerical simulation methodology was employed to analyze the unsteady features of a three-dimensional separated flow and heat transfer around a downward step in a rectangular channel, and to clarify systematically the channel expansion ratio effects upon them. Numerical calculations were carried out using the finite difference method. The Reynolds number Re based on the mean velocity at inlet and the step height was varied from 300 to 1000. The channel expansion ratio ER is 1.5, 2.0 and 3.0 under a step aspect ratio of 36.0. It is found that the flow is steady upto Re = 500 but becomes sensibly unsteady at Re = 700 for all the three expansion ratios. In the case of ER = 2.0, the separated shear layer is most unstable. In the case of ER = 1.5, the longitudinal vortices formed near the side walls of channel are strongest. Nusselt number reaches its maximum in the reattachment flow region and also in the neighborhood of the side wall, and their locations depend greatly upon ER and Re.

Numerical Simulation of Separated Flow and Heat Transfer Around an Inclined Downward Step

2003 ◽  
Vol 2003.39 (0) ◽  
pp. 123-124
Author(s):  
Terukazu OTA ◽  
Aya KITOH ◽  
Kazuaki SUGAWARA ◽  
Hiroyuki YOSHIKAWA
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Separated Flow ◽  
Flow And Heat Transfer

Numerical Simulation of Three-Dimensional Separated Flow and Heat Transfer Around a Surface-Mounted Square Plate

2003 ◽  
Author(s):  
Hiroyuki Yoshikawa ◽  
Keisuke Shimizu ◽  
Terukazu Ota
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Boundary Layer ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Separated Flow ◽  
Numerical Calculations ◽  
Flow And Heat Transfer ◽  
Square Plate ◽  
Separated And Reattached Flow

Direct Numerical Simulation results of three-dimensional laminar separated and reattached flow and heat transfer around a surface-mounted square plate are presented in this paper. Numerical calculations of Navier-Stokes equations and energy one are carried out using the finite difference method with SMAC method. A square plate is presumed to be mounted in a laminar boundary layer developing on a flat surface and to be heated under a constant heat flux. Numerical calculations are made on two boundary layer thicknesses at the plate, and the Reynolds number is varied from 300 to 1000. Details of the separated and reattached flow and the thermal field therein are clarified.

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