基于Canny算法的双圆柱涡振干扰效应试验研究

Experimental research on vortex-induced vibration interference effect of two circular cylinders based on Canny algorithm

基于Canny边缘检测算法,借助于流动可视化手段,研究大长细比双圆柱的涡激振动干扰效应。研究结果表明:当双圆柱串列布置时,下游圆柱通过干扰上游圆柱旋涡的形成与尾流运动,在量纲一下游顺流向位置X*=1.5处对上游圆柱最大振幅A^(*)_(max)的放大作用最大,在X*≥15.0处对上游圆柱的A^(*)_(max)无干扰效应,但上游圆柱的涡振退出风速比单圆柱的略大;上游圆柱改变了下游圆柱的来流条件,当下游圆柱在X*=2.0处时上游圆柱对其A^(*)_(max)的放大作用最大,且在X*=20.0处放大作用仍然存在。当双圆柱并列布置,量纲一横流向间距Y*=1.0时,双圆柱之间的干扰效应对A^(*)_(max)的放大作用最大,此时并列双圆柱可看作组合后的单一柱体发生大幅振动;当Y*=4.0时,双圆柱之间的干扰效应对A^(*)_(max)几乎无影响,但并列双圆柱的涡振锁定区间仍比单圆柱的涡振锁定区间略大。当双圆柱错列布置,下游圆柱位于1<X*<8且1<Y*<5处时,会明显抑制上游圆柱的A^(*)_(max);相比而言,上游圆柱对下游圆柱A^(*)_(max)的干扰效应较弱,当下游圆柱在(0,1D)位置附近时具有较强的放大作用。

Based on the Canny algorithm to edge detection and with the aid of flow visualization method,the vortex-induced vibration interference effect of two circular cylinders with large slenderness ratio was studied.The results show that when the double cylinders are arranged in tandem,by interfering with the formation of the vortex of upstream cylinder and the motion of its wake,the downstream cylinder has the greatest amplifying effect on the maximum amplitude A^(*)_(max)of upstream cylinder in the dimensionless downstream streamwise direction position X*=1.5,and has no interference effect on the A^(*)_(max)of upstream cylinder at X*≥15.0,but the exit wind speed of vortexinduced vibration of upstream cylinder is slightly larger than that of the single cylinder.The upstream cylinder changes the incoming flow conditions of the downstream cylinder,when the downstream cylinder is when X*=2.0,the upstream cylinder has the largest amplification effect on its A^(*)_(max),and the amplification effect still exists when X*=20.0.When the double cylinders are arranged side by side,the amplifying effect on the A^(*)_(max)is the greatest at dimensionless transverse spacing Y*=1.0,and the double cylinders can be regarded as a combined single cylinder and vibrate together with a large amplitude.The interference effect on the A^(*)_(max)is little when Y*=4.0,but the locking range of vortex-induced vibration of double cylinders is still slightly larger than that of the single cylinder.When the double cylinders are arranged in staggered,the A^(*)_(max)of upstream cylinder is obviously suppressed by the downstream cylinder located when 1<X*<8 and 1<Y*<5;and in comparison,the interference effect of the upstream cylinder on the A^(*)_(max)of downstream cylinder is weaker,showing a greatest amplifying effect when the downstream cylinder is near the(0,1D)position.