Influence of Inflow Turbulence on the Flow Characteristics around a Circular Cylinder

Abstract

To study the influence of turbulence on the wind pressure and aerodynamic behavior of smooth circular cylinders, wind tunnel tests of a circular cylinder based on wind pressure testing were conducted for different wind speeds and turbulent flows. The tests obtained the characteristic parameters of mean wind pressure coefficient distribution, drag coefficient, lift coefficient and correlation of wind pressure for different turbulence intensities and of Reynolds numbers. These results were also compared with those obtained by previous researchers. The results show that the minimum drag coefficient in the turbulent flow is basically constant at approximate 0.4 and is not affected by the turbulence intensity. When the Reynolds number is in the critical regime, the lift coefficient increased sharply to 0.76 in the smooth flow, indicating that flow separation has an asymmetry; however, the asymmetry does not appear in the turbulent flow. Drag coefficient decreases sharply at a lower critical Reynolds number in the turbulent flow than in the smooth flow. In the smooth flow, the separation point is about 80° in the subcritical regime; it suddenly moves backwards in the critical regime and remains almost unchanged at about 140° in the supercritical regime. However, the angular position of the separation point will always be about 140° for turbulent flow for the Reynolds number in these three regimes. Turbulence intensity and Reynolds number have a significant effect on the correlation of wind pressures around the circular cylinder. Turbulence will weaken the positive correlation of the same side and also reduce the negative correlation between the two sides of the circular cylinder.

The Wind Loading Characteristics of MAN Type Dry Gas Storage Tank

“…Generally, in the region of 4.0 × 10 5 < Re < 1.0 × 10 6 , the change of C d of the gas tank model with the smooth surface is not significant, and the value of C d is approximately equal to 0.3-0.35. e test results are close to those obtained by Liu et al [30] and Wieselsberger [2]. However, the test results of C d in this paper are smaller than those obtained by Yao et al [29] in the whole Reynolds number region (4.0 × 10 5 <Re < 1.0 × 10 6 ). In order to suppress the end effect of the flow field of the test model, Yao et al [29] fixed the two square end plates on the upper and lower ends of the smooth cylindrical model.…”

“…However, the test results of C d in this paper are smaller than those obtained by Yao et al [29] in the whole Reynolds number region (4.0 × 10 5 <Re < 1.0 × 10 6 ). In order to suppress the end effect of the flow field of the test model, Yao et al [29] fixed the two square end plates on the upper and lower ends of the smooth cylindrical model. erefore, the results of deviation are mainly caused by the three-dimensional effect of the model.…”

“…(1) Detail Results Obtained in Uniform Flow Field. Figure 8(a) shows the drag coefficient (C d ) of the gas tank model with smooth surface (c � 0) in the uniform flow field as well as the results of the previous studies obtain from Yao et al [29], Liu et al [30], Güven et al [31], and Wieselsberger [2]. When Re < 6.0 × 10 5 , the C d is basically unchanged.…”

Similarities of Flow and Heat Transfer around a Circular Cylinder

“…The flow over bluff bodies like spheres [24][25][26] and circular cylinders [27][28][29][30] is a classical problem in fluid mechanics. Yao et al [9] focused on the influence of turbulence on the wind pressure and aerodynamic behavior of smooth circular cylinders. Liang and Duan [12] studied numerically the flow past a yawed circular cylinder using large eddy simulation.…”

“…Flow over an object is omnipresent both in nature [1][2][3] and in many engineering applications [4][5][6]. For instance, the motion of swimming and flying animals [1], growth of stalagmites [2], fall motion of hailstones [3], motion of pollutants in the atmosphere [7], complex motion of the drill string in the field of petroleum engineering [8], and flow over bridge piers, chimney stacks, offshore structures, and tower structures in civil engineering [9], aircrafts in the field of aerospace [10], nuclear fuel rods in the atomic field [5], power battery cooling structures in the field of new energy vehicles [11], heat exchanger tubes in thermal engineering [12], etc. The fluid dynamic drag [13][14][15], active and passive methods for drag reduction [16][17][18], boundary layer flow [19], flow-induced vibration [5], behavior of turbulent fluid motion [20], and instability in the wake shear layer [21][22][23] are of interest in numerous fields.…”