杜晓庆1,2?覮,吴葛菲1,王玉梁1,孙雅慧1.尾流干扰下下游圆柱气动性能的流场机理[J].湖南大学学报:自然科学版,2019,(7):104~112
尾流干扰下下游圆柱气动性能的流场机理
Flow Field Mechanism of Wake Interference Effects on Aerodynamic Characteristics of a Downstream Circular Cylinder
  
DOI:
中文关键词:  双圆柱  大涡模拟  高雷诺数  升力机理  负阻力机理
英文关键词:two circular cylinders  large eddy simulation  high Reynolds number  lift mechanism  negative drag mechanism
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作者单位
杜晓庆1,2?覮,吴葛菲1,王玉梁1,孙雅慧1 (1. 上海大学 土木工程系上海2004442. 上海大学 风工程和气动控制研究中心上海200444) 
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中文摘要:
      采用大涡模拟方法,在高雷诺数(Re=1.4×105)下,以间距比P/D=1.5~4的静止双圆柱为对象,研究了下游圆柱的气动力系数、风压系数以及流场特性随风向角的变化规律,分析了下游圆柱气动力与流场结构的内在关系,基于圆柱壁面摩擦系数和干扰流态探讨了下游圆柱气动性能的流场机理. 研究表明:对于小间距双圆柱(P/D<3),下游圆柱会受到明显的平均负阻力作用,两个圆柱间隙中方向相反的一对回流(串列)以及高速间隙流(错列)是出现负阻力的流场机理;对于小间距错列双圆柱(P/D=1.5~3),下游圆柱还会受到很大的平均升力作用(内侧升力),下游圆柱的风压停滞点偏移、高速间隙流和间隙侧壁面的分离泡是出现这一升力的主要原因;对于间距较大的错列双圆柱(P/D=3~4),下游圆柱也会受到明显的平均升力作用(外侧升力),但其机理与小间距时不同,是由下游圆柱的风压停滞点偏移及其间隙侧气流分离点后移造成的.
英文摘要:
      To clarify the mechanism of wake interference effect on the downstream cylinder, large eddy simulation(LES) method was adopted. The flow around two static staggered circular cylinders was studied at a high Reynolds number of Re=1.4×105, and the ratio of center-to-center pitch (P) to the diameter of the cylinder(D) ranges from P/D=1.5~4. The aerodynamic coefficients, mean pressure distributions, and flow field of the downstream cylinder were discussed along with the changing of incidence angle. The relationship between aerodynamic forces and flow characteristics was analyzed based on the time-averaged wall shear stress and flow structures. The results show that the reasons for the negative drag force of the downstream cylinder at small pitch ratio(P/D<3) lie in two factors, i.e., a pair of recirculation zone with opposite direction for the tandem configuration and the high-speed gap flow for the staggered arrangement with small incidence angles. At small pitch ratios(P/D=1.5~3),the downstream cylinder is subjected to remarkable mean lift coefficient(inner lift),which is caused by the shift of the stagnation point, high-speed gap flow, and separation bubble. At the moderate pitch ratios(P/D=3~4),the mean lift(outer lift) of the downstream cylinder is affected by the shift of the stagnation point and separation point in the gap side.
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