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Applicability of Taylor’s Hypothesis for Estimating the Mean Streamwise Length Scale of LargeScale Structures in the NearNeutral Atmospheric Surface Layer
 Author:
 Han, GuoWen, Wang, GuoHua, Zheng, XiaoJing
 Source:
 Boundarylayer meteorology 2019 v.172 no.2 pp. 215237
 ISSN:
 00068314
 Subject:
 Earth atmosphere, Reynolds number, convection, velocity
 Abstract:
 A field investigation of the mean streamwise length scale Lₓ of largescale structures and the convection velocity is performed in a highReynoldsnumber (Reτ ~ 10⁶) atmospheric surface layer (ASL). Based on selected highquality synchronous data obtained at different streamwise positions, the length scale Lₓ and global convection velocity Uc are extracted in the logarithmic region of the nearneutral ASL at heights of 0.9 m, 1.71 m, 3.5 m, and 5 m. It is found that Uc values are approximately 16% greater than the local mean streamwise velocity component U, and the value of Lₓ obtained from spatiallyseparated measurements is greater than the results estimated from Taylor’s hypothesis using the value of U at the four heights. The mean relative difference between the value of Lₓ and the results estimated by Taylor’s hypothesis using the value of U is approximately 15%. However, the relative difference between the value of Lₓ and the results estimated from Taylor’s hypothesis using the convection velocity Uc instead of the mean streamwise velocity component U is reduced to 1 ± 6% (≈ zero). Thus, the convection velocity Uc is more appropriate than the mean streamwise velocity component U in obtaining Lₓ values in the nearneutral ASL.
 Agid:
 6487605

http://dx.doi.org/10.1007/s10546019004463