Wind borne debris

[44] EFFECTS OF SCALE OF TORNADO-LIKE VORTEX ON FLIGHT OF DEBRIS IN ITS FLOW

Minoru Noda¹, ○Minoru Hachiya², Fumiaki Nagao¹ (1.Tokushima University, 2.Graduate School of Advanced Technology and Science,Tokushima University)

Keywords:Debris flight, Scale of tornado-like flow, Tachikawa number, LES

This paper discusses a stochastic method for estimating shift values from the center of fluctuating displacements at a base-isolated layer when the behaviors are plastic. The results are as follows: 1) Center shift displacement is the average between a local maximum value and a local minimum value obtained from the rain-flow method. 2) The standard deviation of center shift displacement obtained from the rain-flow method and the standard deviation obtained from fluctuating components with a period of more than 3T₀ are almost the same. 3) This paper proposes a method for calculating center shift displacements. The standard deviation of displacements obtained from the proposed method and those calculated from time history analysis are almost the same in the along-wind direction. On the other hand, the values obtained from the proposed method underestimate at high wind speeds of more than 60m/s in the across-wind direction.