维普中文期刊产品整合服务
3篇 您的检索式:作者名="KNAPP Doug"
    题名 作者 年代 出处 被引量
1Evaluation of a gravel transport sensor for bed load measurements in natural flows显示文摘A recent acoustic instrument(Gravel Transport Sensor,GTS) was tested for predicting sediment transport rate(bed load rate) in gravel bed streams. The GTS operation is based on the particle collision theory of submerged obstacles in fluids. When particles collide with the GTS cylinder their momentum is recorded in the form of ping rates. The GTS is attractive for further consideration here because of its potential to provide continuous unattended local bed load measurements,especially in areas found in streams that access may be difficult under extreme conditions. Laboratory experiments coupled with numerical simulations for the same flow conditions were performed in order to determine the conditions under which particles of different size will hit the GTS cylinder and be able to register a ping rate. The GTS was able to detect the number of particles with diameter in the range of 15.9 to 25.4 mm,with reasonable accuracy,if the applied Shields effective stress τe=ττcr was in the range of 0.006 to 0.015. A drawback of the tested prototype GTS,however,was that it exerted increased resistance on the incoming particles. The added drag effects increased the overall resistance that was exerted by the flow on particles and thus increased the likelihood that particles will rest in the ambient region of the cylinder instead of hitting it. Numerical simulation of the flow around the GTS cylinder revealed that changing the prototype geometry from cylindrical to ellipsoid or rhomboid will increase the likelihood of the particles hitting the instrument under the same flow conditions failed by the original tested GTS cylinder.Athanasios N.(Thanos) PAPANICOLAOU Mohamed ELHAKEEM Doug KNAPP 2009International Journal of Sediment Research2009,24,1:3
2Ecology versus issue interpretation : the analysis of two different messages显示文摘KNAPP Doug BARRIE Elizabeth 1998Journal of Interpretation Research1998,3,1:1
3Ecology Versus Issue Interpretation: The Analysis Of Two Different Messages 显示文摘Doug Knapp Elizabeth Barrie 1998Journal of Interpretation Research1998,3,1:1
返回顶部 每页显示:
共1页 首页 上一页 第1页 下一页 末页 /1 跳转

网站首页 | 关于我们 | 联系我们 | 产品服务 | 客服中心 | 广告服务 | 版权声明 | 网站联盟 | 友情链接 | 售卡网点

版权所有© 渝B2-20050021-1 渝公网安备 50019002500403号 违法和不良信息举报中心

互联网出版许可证 新出网证(渝)字10号 全国400电话 - 免长途话费