| Currently,it is very important to study the influence of thermal convection on the atmospheric surface layer high Reynolds number wall turbulence,whether it is for high Reynolds number wall turbulence or natural disasters induced by turbulence.Therefore,this research conducts an experimental study on the effects of the incidental intense thermal convection events on the atmospheric surface layer wall turbulence based on a large number of field observation data from Qingtu Lake Observation Array?QLOA?.Through the study of second-order statistics of different scales and high-order statistics,the influence of the incidental intense thermal convection events is quantitatively analyzed.A new parameter?that can characterize the effects of the incidental intense thermal convection events is proposed.Based on this new parameter,a method for troubleshooting the events is presented.In addition,the influence of the incidental intense heat convection events on the turbulent structure is also researched,and the possible reasons that affect the very-large-scale motions evolution mechanism in the atmospheric surface layer are presented.The innovative results obtained in this paper are:?1?In the near-neutral atmospheric surface layer data selected by|z/L|?27?0.1 as a standard screening,there is still a certain proportion of data containing the incidental intense thermal convection events;?2?A new parameter?is proposed to better characterize the spatial variation of the second-order statistics,high-order statistics,turbulent structural morphs and the amplitude modulation between wall-normal low frequency fluctuations and high frequency fluctuations in the near-neutral atmospheric surface layer;?3?Based on the existing data screening methods,three methods for detecting the incidental intense heat convection events are proposed,i.e.,comparing the?of different data,contrasting Ap and A3pp with Gaussian statistic and contrasting the amplitude modulation between the wall-normal low frequency fluctuations and high frequency fluctuations of different data;?4?The incidental intense thermal convection events may be one of the reasons for the“Top-Down”evolution mechanism of the very-large-scale motions in the atmospheric surface layer. |
PDF Full Text Request