方柱绕流粒子图像测速试验与数值模拟

Particle Image Velocimetry Study and Numerical Simulation of Turbulent near Wake of Square Cylinder

摘要:

采用粒子图像测速设备PIV (particle image velocimetry),进行了雷诺数为2.2×104的方柱绕流试验，与公认的采用LDV (laser doppler velocimetry)的试验结果吻合较好，验证了本风洞中PIV试验系统的有效性.在进一步的比选中，通过计算方柱的阻力系数和斯特劳哈尔数以及流场的速度剖面和湍动能剖面，比较了几种常用湍流时均模型的计算结果与试验结果的差别.结果表明,采用基于剪应力传输的湍动能—耗散率模型(k—ω SST),能够得到与试验吻合较好的计算结果.

关键词:方柱绕流; 雷诺时均湍流模型; 粒子图像测速技术(PIV); 阻力系数; 斯特劳哈尔数; 湍动能

Abstract:

The result of the experiment of vortex shedding from a square cylinder is important in comparing the precision of different models including Reynolds averaged Navior Stokes(RANS) models in computational fluid dynamics(CFD). The experiment of vortex shedding from a square cylinder with the Reynolds number of 2.2×104 is done using particle image velocimetry (PIV). A comparison with the results of Laser Doppler Velocimetry(LDV) experiments carried out by other researchers in the same Reynolds number shows that the PIV instruments is effective in obtaining turbulent wake of bodies. Comparisons are also conducted with different RANS models(Realizable k-ε model，k-ω shear stress transport(SST) model and Reynolds stress model) of the coefficients of damping ratio,strouhal number and the velocity profiles and turbulent kinetic energy profiles. It is discovered that the result of the k-ω SST model is much more precise in the aerodynamic parameter identification and flow field simulation mentioned above.

Key words:square cylinder; Reynoids averaged Navior Stokes model; particle image velocimeting; damping coefficient; Strouhal number; turbulent kinetic energy