Numerical study on dynamics of a tornado-like vortex with touching down by using the LES turbulence model

作者：Ishihara Takeshi^*; Liu Zhenqing

来源：Wind and Structures, 2014, 19(1): 89-111.

DOI：10.12989/was.2014.19.1.089

• dynamics of tornado-like vortex with touching down
• LES
• turbulent flow fields
• force balances
• organized swirl motion
• power spectrum
• gust speed

The dynamics of a tornado-like vortex with touching down is investigated by using the LES turbulence model. The detailed information of the turbulent flow fields is provided and the force balances in radial and vertical directions are evaluated by using the time-averaged axisymmetric Navier-Stokes equations. The turbulence has slightly influence of the mean flow fields in the radial direction whereas it shows strong impacts in the vertical direction. In addition, the instantaneous flow fields are investigated to clarify and understand the dynamics of the vortex. An organized swirl motion is observed, which is the main source of the turbulence for the radial and tangential components, but not for the vertical component. Power spectrum analysis is conducted to quantify the organized swirl motion of the tornado-like vortex. The gust speeds are also examined and it is found to be very large near the center of vortex.

• 出版日期2014-7