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91.
92.
High-resolution particle-image velocimetry (PIV) measurements are made in the streamwise-wall-normal plane of turbulent channel
flow at Reτ=566, 1184 and 1759, facilitating documentation of the population trends and core diameters of small-scale spanwise vortices.
Swirling strength, an unambiguous vortex-identification criterion and hence a local marker of rotation, is used to extract
small-scale spanwise vortex cores from the instantaneous velocity fields. Once the small-scale vortices are properly extracted
from the PIV realizations, their characteristics are studied in detail. The present results indicate that the very-near-wall
region (y < 0.1h) is densely populated by spanwise vortices with clockwise (negative) rotation. This behavior supports the notion that hairpin-like
vortices are generated very close to the wall and grow into the outer layer as they advect downstream. In contrast, counterclockwise
(positive) spanwise vortices are scarce in the very-near-wall region, but their presence steadily increases within the logarithmic
layer presumably due to a localized generation mechanism. The average core diameter of negative spanwise vortices is found
to be larger than the average diameter of positive vortices, with few positive vortices having core diameters exceeding 80y. 相似文献
93.
A. Blacha M. Cardona N.E. Christensen S. Ves H. Overhof 《Solid State Communications》1982,43(3):183-187
We have investigated theoretically and experimentally the dependence of the spin-orbit splitting of the edge excitons in CuCl, CuBr, and CuI on volume. The results indicate a large contribution of the change in p(halogen)-d(Cu) hybridization with volume, especially for CuCl. 相似文献
94.
We prove a positive mass theorem on ALF manifolds, i.e. complete noncompact manifolds that are asymptotic to a circle fibration
over a Euclidean base, with fibers of asymptotically constant length. 相似文献
95.
The splitting of the spin degeneracy of the lowest conduction band of GaAs for along [110] is calculated by · perturbation theory as well as by means of the self-consistent LMTO method. The magnitude and the sign of the calculated splitting agree with recent measurements of the spin precession in spin- polarized photoemission from GaAs [110] surfaces. 相似文献
96.
97.
98.
S.Brøgger Christensen Ulla Rasmussen Carsten Christophersen 《Tetrahedron letters》1980,21(39):3829-3830
The major skin irritating constituent of the root of Thapsia garganica L. has been shown to be a hexaoxygenated-C6-guaianolide esterificated with four carboxylic acids. 相似文献
99.
100.