LOCAL ISOTROPY AND ANISOTROPY IN THE SHEARED AND HEATED ATMOSPHERIC SURFACE-LAYER

NCU Institutional Repository > 工學院 > 土木工程研究所 > 期刊論文 > Item 987654321/26334

jsp.display-item.identifier=請使用永久網址來引用或連結此文件: http://ir.lib.ncu.edu.tw/handle/987654321/26334

题名:	LOCAL ISOTROPY AND ANISOTROPY IN THE SHEARED AND HEATED ATMOSPHERIC SURFACE-LAYER
作者:	KATUL,GG;PARLANGE,MB;ALBERTSON,JD;CHU,CR
贡献者:	土木工程研究所
关键词:	REYNOLDS-NUMBER;BOUNDARY-LAYER;TURBULENT JET;TEMPERATURE;HYPOTHESIS;VELOCITY
日期:	1995
上传时间:	2010-06-29 17:11:02 (UTC+8)
出版者:	中央大學
摘要:	Longitudinal velocity and temperature measurements above a uniform dry lakebed were used to investigate sources of eddy-motion anisotropy within the inertial subrange. Rather than simply test the adequacy of locally isotropic relations, we investigated directly the sources of anisotropy, These sources, in a daytime desert-like climate, include: (1) direct interaction between the large-scale and small-scale eddy motion, and (2) thermal effects on the small-scale eddy motion. In order to explore these two anisotropy sources, we developed statistical measures that are sensitive to such interactions. It was found that the large-scale/small-scale interaction was significant in the inertial subrange up to 3 decades below the production scale, thus reducing the validity of the local isotropy assumption. The anisotropy generated by thermal effects was also significant and comparable in magnitude to the former anisotropy source. However, this thermal anisotropy was opposite in sign and tended to counteract the anisotropy generated by the large-scale/small-scale interaction, The thermal anisotropy was attributed to organized ramp-like patterns in the temperature measurements, The impact of this anisotropy cancellation on the dynamics of inertial subrange eddy motion was also considered. For that purpose, the Kolmogorov-Obukhov structure function equation, as derived from the Navier-Stokes equations for locally isotropic turbulence, was employed. The Kolmogorov-Obukhov structure function equation in conjunction with Obukhov's constant skewness closure hypothesis reproduced the measured second- and third-order structure functions. Obukhov's constant skewness closure scheme, which is also based on the local isotropy assumption, was verified and was found to be in good agreement with the measurements. The accepted 0.4 constant skewness value derived from grid turbulence experiments overestimated our measurements. A suggested 0.26 constant skewness value, which we derived from Kolmogorov's constant, was found to be adequate.
關聯:	BOUNDARY-LAYER METEOROLOGY
显示于类别:	[土木工程研究所] 期刊論文

文件中的档案:

档案	描述	大小	格式	浏览次数
index.html		0Kb	HTML	444	检视/开启

在NCUIR中所有的数据项都受到原著作权保护.

社群 sharing

数据加载中.....