ABSTRACT
The two-dimensional laminar steady mixed convective flow and heat transfer around two identical tandem square cylinders confined in a horizontal channel are simulated by the high-accuracy multidomain pseudo-spectral method. The blockage ratio of the channel is chosen as 0.1, whereas the spacing between the cylinders is fixed with four widths of the cylinder. The Prandtl number is fixed at 0.7, the Reynolds number (Re) is studied in the range 5 ≤ Re ≤ 60, and the Richardson number (Ri) demonstrating the influence of thermal buoyancy ranges from 0 to 1. Numerical results reveal that, with the thermal buoyancy effect, the mixed convective flow remains steady. The variations of the overall drag and lift coefficients and the Nusselt numbers, are presented and discussed. Furthermore, the influence of thermal buoyancy on fluid flow and heat transfer is discussed and analyzed.
Nomenclature
B | = | blockage ratio |
Cd | = | drag coefficient |
Cl | = | lift coefficient |
Cp | = | pressure coefficient |
d | = | width of the cylinder |
g | = | gravitational acceleration |
G | = | spacing between cylinders |
Gr | = | Grashof number |
h | = | local heat transfer coefficient |
H | = | width of the computational domain |
k | = | thermal conductivity of the fluid |
n | = | index of iteration |
N | = | total number of iterations in one period |
Nu | = | overall Nusselt number |
Nul | = | local Nusselt number |
n | = | unit normal vector |
p | = | dimensionless pressure |
Pr | = | Prandtl number |
Re | = | Reynolds number |
Ri | = | Richardson number |
u, v | = | dimensionless velocity components |
Umax | = | the maximum velocity at the inlet |
x, y | = | directions of the Cartesian coordinate |
Xd | = | downstream distance |
Xu | = | upstream distance |
Greeks | = | |
α | = | thermal diffusivity of the fluid |
β | = | coefficient of volume expansion |
ν | = | kinematic viscosity of the fluid |
θ | = | dimensionless temperature |
τ | = | pseudo-time |
Nomenclature
B | = | blockage ratio |
Cd | = | drag coefficient |
Cl | = | lift coefficient |
Cp | = | pressure coefficient |
d | = | width of the cylinder |
g | = | gravitational acceleration |
G | = | spacing between cylinders |
Gr | = | Grashof number |
h | = | local heat transfer coefficient |
H | = | width of the computational domain |
k | = | thermal conductivity of the fluid |
n | = | index of iteration |
N | = | total number of iterations in one period |
Nu | = | overall Nusselt number |
Nul | = | local Nusselt number |
n | = | unit normal vector |
p | = | dimensionless pressure |
Pr | = | Prandtl number |
Re | = | Reynolds number |
Ri | = | Richardson number |
u, v | = | dimensionless velocity components |
Umax | = | the maximum velocity at the inlet |
x, y | = | directions of the Cartesian coordinate |
Xd | = | downstream distance |
Xu | = | upstream distance |
Greeks | = | |
α | = | thermal diffusivity of the fluid |
β | = | coefficient of volume expansion |
ν | = | kinematic viscosity of the fluid |
θ | = | dimensionless temperature |
τ | = | pseudo-time |
Acknowledgments
The helpful suggestions from Tingting Wu, Zhiheng Wang, and Zhongguo Sun are appreciated.