Abstract
A numerical study of flow characteristics around eight elliptic cross-section cylinders in an octagonal configuration is presented. The axis ratio of elliptic cylinder is taken as 1:2. Three spacings between the cylinders (0.07 m, 0.14 m and 0.2 m), two angles of attack (α=0° and α=15°) and two Reynolds numbers (Re=4060 and Re=45800) are considered to investigate the parametric influences. The flow is modelled using three-dimensional large eddy simulation. Simulations are performed by utilizing ANSYS Fluent software. The results comprise of flow patterns and force coefficients (drag and lift). It is seen that both the drag and lift forces acting on the cylinders vary with the spacings values, angle of attack and Reynolds numbers. The lift force peaks at α=15° and Reynolds number 45800. The drag force on the upstream cylinder reaches its peak at α=0° and Reynolds number 4060. It is observed that the drag on the upstream cylinders decreases as the value of the Reynolds number increases. Contours of velocity and subgrid turbulent viscosity are also presented. Moreover, it is concluded from the present study that the effect of change in the Reynolds number on flow characteristics is more significant as compared to the change in the spacing between the cylinders.
Highlights
Fluid interaction with multiple bluff bodies has gained much significance because of its various applications in diverse fields of engineering
Zou and Lin [3] found that the cylinders in the downstream direction experience lower forces than the cylinders which are placed in the upstream direction of the fluid flow
The present study aims to numerically simulate the flow over eight elliptic cylinder arrays placed in octagonal arrangement using large-eddy simulation
Summary
Fluid interaction with multiple bluff bodies has gained much significance because of its various applications in diverse fields of engineering. Drummond and Tahir [1] found the solutions for fluid past arrays of cylinders with different arrangements of cylinders. The different arrangements of cylinders taken were square, triangular and rectangular. The direction of flow taken was perpendicular to the cylinder axes. Donald and Anthony [2] investigated the pressure drop required for the fluid to flow through arrays of randomly aligned cylinders. Zou and Lin [3] found that the cylinders in the downstream direction experience lower forces than the cylinders which are placed in the upstream direction of the fluid flow. Alternate wide and narrow wakes are generated at different instants of time. Different values of drag and lift force coefficients values were obtained for the arrays of cylinders considered for the numerical simulation
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