. Collected reprints / Atlantic Oceanographic and Meteorological Laboratories [and] Pacific Oceanographic Laboratories. Oceanography RIPPLES (Cross-lamination) PLANE BED (Even lamination). NO SEDIMENT MOVEMENT D (cm) FIGURE 11. Bed forms in relation to stream power and grain size. Data of G. P. Williams, H. P. Guy, D. B. Simons, and E. V. Richardson. From Allen (1970). MICROSCALE LONGITUDINAL BED FORMS (PARTING lineation). It has been repeatedly suggested that the logarithmic boundary layer tends to be so patterned, although an ade
. Collected reprints / Atlantic Oceanographic and Meteorological Laboratories [and] Pacific Oceanographic Laboratories. Oceanography RIPPLES (Cross-lamination) PLANE BED (Even lamination). NO SEDIMENT MOVEMENT D (cm) FIGURE 11. Bed forms in relation to stream power and grain size. Data of G. P. Williams, H. P. Guy, D. B. Simons, and E. V. Richardson. From Allen (1970). MICROSCALE LONGITUDINAL BED FORMS (PARTING lineation). It has been repeatedly suggested that the logarithmic boundary layer tends to be so patterned, although an adequate analytic model has not yet been devised (Schlichting, 1962, pp. 500-509). Kline (1967) and Kline et al. (1967) have conducted dye experiments in flumes which suggest that the laminar sublayer and the lower part of the buffer sublayer of the turbulent boundary layer have a structure characterized by vig- orous transverse components of flow (see discussion, p. 94). Dye introduced into the boundary layer forms into bands that are more slowly moving than those in the intervening water zones. Although the streaks are randomly generated, they have a mean transverse spac- ing of Xr = \00i>u* in which v is the kinematic viscosity and u> is the shear velocity (Kline, 1967). The response to helically structured boundary flow over a cohesionless particulate substrate is, however, well known; it is the ubiquitous parting lineation (Sorby, 1859), so named for the tendency of flagstones (silty sandstones with strong bedding fissility) to exhibit lineations on bedding planes. Closer examination reveals a waveform bedding surface whose undulations parallel flow direction; ridges are a few grain diameters high and are up to several centimeters apart (Allen, 1964; 1968a, pp. 31-32); see Fig. 12. There is clear evidence for the divergence and convergence of bottom flow in that the azimuths of long grains are bimodal, although this evidence does not re- solve the secondary flow pattern
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