用PIV方法研究底面粗糙度对类鱼雷形涡的影响
The flow field of a laboratory-simulated tornado was studied by means of 2-D ParticleImage Velocimetry or PIV technique with the purpose of investigating the effects of roughness onthe near-ground tornado-like vortex structure and its velocity distribution. The results show the flowregime transition from multi-celled vortices over the smooth surface at a higher swirl ratio to singleordual-celled vortices with roughness. Significant difference in velocities and turbulencecharacteristics is observed as a result of increasing ground roughness. This work is part of a projectthat seeks better understanding of the near-ground flow field and resulting wind-induced loads onstructures in a tornado.