Fluid flow and heat transfer around square cylinder with dual splitter plates arranged at novel positions

2021 ◽  
pp. 095440622110578
Author(s):  
Prasenjit Dey
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Drag Coefficient ◽  
Lift Coefficient ◽  
Mean Square ◽  
Square Cylinder ◽  
Fluid Forces ◽  
Flow And Heat Transfer ◽  
Splitter Plates ◽  
The Mean

In this paper, the effect of the dual splitter plates on the fluid flow and heat transfer characteristics around a regular square cylinder for a low Reynolds number flow ( Re = 100) is presented. The placement of the dual splitter plates is novel of its kind as these plates are located at the top and bottom surfaces of the cylinder rather than the conventional locations, that is, at the upstream and downstream of the cylinder. Here, two splitter plates of the same width ( w) with varying lengths and location are considered. A numerical investigation is performed using the open-source code, OpenFOAM. A base solver, icoFOAM is used after modifying the code by incorporating the energy equation in it. The primary wake bubble is found closer to the cylinder rear surface when the dual plates are introduced. It is also noticed that the separation angle and the recirculation length are smaller in the dual plates cases than that are in the cases without the dual plates. A mixed effect of the dual plates on the fluid forces is observed in the present study. A maximum reduction on the mean drag coefficient and root mean square of the lift coefficient is found as 3% and 24%, and maximum increment as 75% and 87%, respectively. However, a substantial enhancement on the overall heat transfer is noticed with the dual plates compared to that of the bare cylinder. A maximum enhancement of 40% is observed in the heat transfer around the square cylinder. In addition, thermal-hydraulic performance is calculated for finding the trade-off between the fluid forces and the heat transfer. The maximum value of thermal-hydraulic performance is found as 1.35 in the present study depending on the mean drag coefficient and 3.65 depending on the root mean square of the lift coefficient. Further, a novel combined thermo-fluid regime is defined for the square cylinder with dual splitter plates from which the location of the plates can be determined according to the demand on the heat transfer and fluid forces.

The Effect of Blockage Ratio on Fluid Flow and Heat Transfer around a Confined Square Cylinder under the Effect Thermal Buoyancy

2018 ◽  
Vol 16 ◽  
pp. 1-11
Author(s):  
Houssem Laidoudi
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Numerical Study ◽  
Convection Heat Transfer ◽  
Blockage Ratio ◽  
Square Cylinder ◽  
Total Drag ◽  
Thermal Buoyancy ◽  
2D Simulation ◽  
Flow And Heat Transfer

2D simulation is carried out to determine exactly the effect of blockage ratio on the flow and mixed convection heat transfer characteristics of Newtonian fluid across a square cylinder confined in horizontal channel, the numerical study is investigated in the range of these conditions:Re= 10 to 30,Ri= 0 to 1 and blockage ratioβ= 1/10 to 1/2. The flow structure and temperature field are visualized in terms of streamlines and isotherm contours. The total drag coefficient and average Nusselt number are also reported to show the combined effects of thermal buoyancy, Reynolds number and blockage ratio on the hydrodynamic flow forces and heat transfer rate. The obtained results showed that the effect of thermal buoyancy on fluid flow and heat transfer becomes more pronounced by decreasing the blockage ratio.

Fluid Flow and Heat Transfer in a Lid-Driven Cavity Due to an Oscillating Thin Fin: Transient Behavior

2004 ◽  
Vol 126 (6) ◽  
pp. 924-930 ◽  
Author(s):  
Xundan Shi ◽  
J. M. Khodadadi
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Computational Study ◽  
Transient Behavior ◽  
Phase Lag ◽  
Dimensionless Time ◽  
Number Range ◽  
Flow And Heat Transfer ◽  
Periodic State ◽  
The Mean

A finite-volume-based computational study of transient laminar flow and heat transfer (neglecting natural convection) within a lid-driven square cavity due to an oscillating thin fin is presented. The lid moves from left to right and a thin fin positioned perpendicular to the right stationary wall oscillates in the horizontal direction. The length of the fin varies sinusoidally with its mean length and amplitude equal to 10 and 5 percent of the side of the cavity, respectively. Two Reynolds numbers of 100 and 1000 for a Pr=1 fluid were considered. For a given convection time scale tconv, fin’s oscillation periods (τ) were selected in order to cover both slow τ/tconv>1 and fast τ/tconv<1 oscillation regimes. This corresponded to a Strouhal number range of 0.005 to 0.5. The number of the cycles needed to reach the periodic state for the flow and thermal fields increases as τ/tconv decreases for both Re numbers with the thermal field attaining the periodic state later than the velocity field. The key feature of the transient evolution of the fluid flow for the case with Re=1000 with slow oscillation is the creation, lateral motion and subsequent wall impingement of a CCW rotating vortex within the lower half of the cavity. This CCW rotating vortex that has a lifetime of about 1.5τ brings about marked changes to the temperature field within a cycle. The dimensionless time for the mean Nusselt numbers to reach their maximum or minimum is independent of the frequency of the fin’s oscillation and is dependent on the distance between the oscillating fin and the respective wall, and the direction of the primary CW rotating vortex. The phase lag angle between the oscillation of the fin and the mean Nusselt number on the four walls increases as the distance between the fin and the respective wall increases.

Fluid Flow and Heat Transfer in a Lid-Driven Cavity Due to an Oscillatory Thin Fin: Transient Behavior

2004 ◽  
Author(s):  
Xundan Shi ◽  
J. M. Khodadadi
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Computational Study ◽  
Transient Behavior ◽  
Phase Lag ◽  
Dimensionless Time ◽  
Number Range ◽  
Flow And Heat Transfer ◽  
Periodic State ◽  
The Mean

A finite-volume-based computational study of transient laminar flow and heat transfer (neglecting natural convection) within a lid-driven square cavity due to an oscillating thin fin is presented. The lid moves from left to right and a thin fin positioned perpendicular to the right stationary wall oscillates in the horizontal direction. The length of the fin varies sinusoidally with its mean length and amplitude equal to 10 and 5 percent of the side of the cavity, respectively. Two Reynolds numbers of 100 and 1000 with a Pr = 1 fluid were considered. For a given convection time scale (tconv), fin’s oscillation periods (τ) were selected in order to cover both slow (τ/tconv&gt;1) and fast (τ/tconv&lt;1) oscillation regimes. This corresponded to a Strouhal number range of 0.005 to 0.5. The number of the cycles needed to reach the periodic state for the flow and thermal fields increases as τ/tconv decreases for both Re numbers with the thermal field attaining the periodic state later than the velocity field. The key feature of the transient evolution of the fluid flow for the case with Re = 1000 with slow oscillation is the creation, lateral motion and subsequent wall impingement of a CCW rotating vortex within the lower half of the cavity. This CCW rotating vortex that has a lifetime of about 1.5τ brings about marked changes to the temperature field within a cycle. The dimensionless time for the mean Nusselt numbers to reach their maximum or minimum is independent of the frequency of the fin’s oscillation and dependent on the distance between the oscillating fin and the respective wall, and the direction of the primary CW rotating vortex. The phase lag angle between the oscillation of the fin and the mean Nusselt number on the four walls increases as the distance between the fin and the respective wall increases.

scholarly journals A numerical study on convection around a square cylinder using Al2O3-H2O nanofluid

2014 ◽  
Vol 18 (4) ◽  
pp. 1305-1314 ◽  
Author(s):  
Mohammad Valipour ◽  
Reza Masoodi ◽  
Saman Rashidi ◽  
Masoud Bovand ◽  
Mojtaba Mirhosseini
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Volume Fraction ◽  
Numerical Study ◽  
Pressure Coefficient ◽  
Simple Algorithm ◽  
Square Cylinder ◽  
Flow And Heat Transfer ◽  
Recirculation Length ◽  
Energy Equations

In this paper, a numerical simulation has been performed to study the fluid flow and heat transfer around a square cylinder utilizing Al2O3-H2O nanofluid over low Reynolds numbers. Here, both Reynolds and Peclet numbers are varied within the range of 1 to 40and the volume fraction of nanoparticles (?) is varied within the range of 0<?<0.05. Two-dimensional and steady mass continuity, momentum and energy equations have been discretized using Finite Volume Method (FVM). SIMPLE algorithm has been applied for solving the pressure linked equations. The effect of volume fraction of nanoparticles on fluid flow and heat transfer were investigated numerically. It was found that at a given Reynolds number, the Nusselt number, drag coefficient, recirculation length, and pressure coefficient increases by increasing the volume fraction of nanoparticles.

Numerical simulation of the flow and heat transfer around a cylinder with a pulsating approaching flow at a low Reynolds number

2001 ◽  
Vol 215 (1) ◽  
pp. 105-119 ◽  
Author(s):  
G Papadakis ◽  
G Bergeles
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Vortex Shedding ◽  
Mean Value ◽  
Velocity Pulsation ◽  
Mean Square ◽  
Front Part ◽  
Lower Side ◽  
Flow And Heat Transfer ◽  
The Mean

Two-dimensional numerical simulations of flow and heat transfer around a cylinder at a Reynolds number Re= 100 have been performed in order to investigate the effect of imposed inlet velocity pulsation on the heat transfer and flow fields. First the code is validated against existing results from the literature and then several external frequencies are examined. The numerical results confirm the existence of a vortex shedding lock-on regime where the wake behaves in a very ordered manner (completely periodic). Outside the lock-on region the flow is quasiperiodic. The length and centre of the mean recirculating zone downstream of the cylinder are also affected by the external pulsation. Regarding heat transfer, the results indicate that by imposing an external velocity pulsation, the root mean square (r.m.s.) of the local Nusselt number Nu increases, but the mean value increases only in the area downstream of the separation point. The mechanism responsible for this is identified: hot fluid is engulfed by stronger vortices (compared with the steady approaching flow case) shed from the upper and lower side of the cylinder and returned close to the downstream stagnation point. This mechanism also explains the observed variation in Nu with time. In the front part of the cylinder, the Nu varies almost sinusoidally and closely follows the imposed external velocity pulsation. The results indicate also that there is a range of external frequencies where the time and spatially averaged Nu number is maximized.

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