薄平板复气动导纳函数的试验与数值模拟研究

Experimental and numerical simulation studies on complex aerodynamic admittance functions of thin plate section

提出了一种分离频率识别复气动导纳的方法。首先推导了分离的单一频率下能够有效识别6个复气动导纳的理论公式;然后通过一种主动格栅产生顺风向和竖向的正余弦脉动分量,采用双天平水平测力装置测量模型上的抖振力;最后通过分析脉动风和抖振力的时程曲线,得到薄平板的6个复气动导纳函数,并与数值模拟结果相比较。结果显示:气动导纳的试验值均小于数值模拟结果;Sears函数不能作为桥梁断面阻力导纳函数的近似值;复气动导纳相位的试验值与数值模拟结果基本接近。

The separated frequency-by-frequency method for estimating complex aerodynamic admittance functions （CAAFs） is presented and formulas are deduced. The longitudinal and vertical components are generated by an active turbulence generator and measured by a Cobra Probe. A horizontal setup of measuring force with double force balances is developed and used to measure the aerodynamic forces acting on sectional models suspended in wind tunnel. Making use of experimental data, six CAAFs are successfully identified. Meanwhile, CAAFs are investigated using the numerical simulation technique of CFD （Computational Fluid Dynamics）. The experimental results are compared with the numerical ones and it is shown that the experinaental results are less than the numerical ones, Sears function can not be regarded as the approximation of drag admittance functions of bridge sections and the phases of the estimated admittance functions are of good agreed with those of the numerical results.