A theoretical and experimental investigation of energy-containing scales in the dynamic sublayer of boundary-layer flows

NCU Institutional Repository > 工學院 > 土木工程研究所 > 期刊論文 > Item 987654321/26300

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/987654321/26300

题名:	A theoretical and experimental investigation of energy-containing scales in the dynamic sublayer of boundary-layer flows
作者:	Katul,G;Chu,CR
贡献者:	土木工程研究所
关键词:	LONGITUDINAL VELOCITY FLUCTUATIONS;SURFACE-LAYER;HEAT FLUXES;PIPE-FLOW;TURBULENCE;SIMILARITY;MOMENTUM;SPECTRA;MODEL
日期:	1998
上传时间:	2010-06-29 17:10:16 (UTC+8)
出版者:	中央大學
摘要:	The existence of universal power laws at low wavenumbers (K) in the energy spectrum (E-u) of the turbulent longitudinal velocity (u) is examined theoretically and experimentally for the near-neutral atmospheric surface layer. Newly derived power-law solutions to Tchen's approximate integral spectral budget equation are tested for strong-and weak-interaction cases between the mean flow and turbulent vorticity fields. To verify whether these solutions reproduce the measured E-u at low wavenumbers, velocity measurements were collected in the dynamic sublayer of the atmosphere at three sites and in the inner region of a laboratory open channel. The atmospheric surface layer measurements were carried out using triaxial sonic anemometers over tall corn, short grass, and smooth desert-like sandy soil. The open channel measurements were performed using a two-dimensional boundary-layer probe above a smooth stainless steel bed. Comparisons between the proposed analytical solution for E-u, the dimensional analysis by Kader and Yaglom, and the measured Haar wavelet E-u spectra are presented. It is shown that when strong interaction between the mean flow and turbulent vorticity field occurs, wavelet spectra measurements, predictions by the analytical solution, and predictions by the dimensional analysis of Kader-Yaglom (KY) are all in good agreement and confirm the existence of a -1 power law in E-u(= CuuU(2) K-1, where C-uu is a constant and u is the friction velocity). The normalized upper wavenumber limit of the -1 power law (Kz = 1, where z is the height above the zero-plane displacement) is estimated using two separate approaches and compared to the open channel and atmospheric surface-layer measurements. It is demonstrated that the measured upper wavenumber limit is consistent with Tchen's budget but not with the KY assumptions. The constraints as to whether the mean flow and turbulent vorticity strongly interact are considered using a proposed analysis by Panchev. It is demonstrated that the arguments by Panchev cannot be consistent with surface-layer turbulence. Using dimensional analysis and Heisenberg's turbulent viscosity model, new constraints are proposed. The new constraints agree with the open channel and atmospheric surface-layer measurements, Townsend's 'inactive eddy motion hypothesis', and the Ferry et al. analysis.
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	491	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.....