基于近海海面观测的台风黑格比风特性研究

根据在博贺海洋观测站测得的0814台风黑格比三维风速时程,首先探讨了实测数据质量的判别准则及处理方法,进而研究了平均风场特性:风剖面、风攻角、梯度风高度以及脉动风场特性:湍流强度、阵风因子、时间尺度、积分尺度、脉动风速谱等。研究结果表明:近海海面指数律风剖面指数a远小于建筑结构荷载规范推荐值;台风风场结构本身存在3°～7°正攻角;在近海海面上阵风因子均值为1.23;顺风向湍流强度平均值为0.10,三向湍流强度的比值为1∶0.80∶0.43;水平向时间尺度基本上均小于30s,竖向时间尺度均小于10s;纵向和横向积分尺度较为接近,大于竖向积分尺度;不同区域的实测风速谱与各经验风速谱均存在一定差异,与von Karman谱吻合相对较好。

Study on wind characteristics of typhoon Hagupit based on offshore sea surface measurements

Wind data are often measured near seaside or over flat smooth terrain inland,in which case the wind characteristics were influenced by topography and typhoon structure synthetically.In this paper,based on the field measured data of typhoon Hagupit on Bohe station,firstly the principles to detect and amend the spikes were proposed.Secondly,wind characteristics including wind profile,angle of attack,gradient height,turbulence intensity,gust facotr,time scale,length scale and power density spectra et.al,were carefully analyzed.The results show that the exponential index a of power law profile is less than the recommended value for onshore wind in load code for the design of building structures;the angle of attack induced by typhoon field is about 3°~7°;the 3s gust facotr is 1.23 over sea surface;the longitudinal turbulence intensity is 0.1 and the ratio among the three dimensional trbulence intensity is 1∶0.80∶0.43;the horizontal time scales are less than 30s and the vertical time scales are less than 10s;the length scales in both the two horizontal directions are nearly equal,but greater than the values in vertical direction;the field measured power density spectra follow von Karman spectral model better in contrast wity other empirical power spectral model.