Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9479282 | Continental Shelf Research | 2005 | 9 Pages |
Abstract
A new method is developed to estimate the mean bed roughness from time series of mean velocities collected at two levels near the bed. Under the assumption of the law of the wall, the bed roughness is estimated by plotting time series of mean velocities measured at a lower level against those at an upper level. A simple criterion is also derived to censor the velocity data when only some of the data are of logarithmic distribution. This new method is then applied to estimate the bed roughness at three study sites (Site-1, 2, 5) in Moreton Bay, one of the semi-enclosed largest bays in Australia. The mean velocities were measured for 10Â min every 30Â min at 34 and 100Â cm above the seabed at the northern entrance (h=16m, Ï50=0.2mm, Site-1), the bay centre (h=15m, mud, Site-2) and Deception Bay (h=6m, mud, Site-5) in the Bay. Based on the mean velocities measured for 5 days, the bed roughness is estimated as ks=0.07, 1.92 and 0.52Â cm at Site-1, 2 and 5, and correspondingly, the drag coefficient is CD=1.42Ã10-3, 2.96Ã10â3 and 2.13Ã10â3.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Geology
Authors
Zai-Jin You,