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

Abstract

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.