FORMULA ON ENERGY LOSSES AT THREE-WAY CIRCULAR DROP MANHOLE UNDER SURCHARGE FLOW
1Member of JSCE, Professor, Dept. of Civil and Environmental Eng., National Institute of Technology, Matsue College (14-4 Nishi-ikuma, Matsue, Shimane 690-8518, Japan) E-mail: arao@matsue-ct.jp 2Member of JSCE, Electric Power Development Co., Ltd. (15-1 Ginza 6-chome, Chuo-ku, Tokyo 104-8165, Japan) E-mail: Shunsuke_Hiratsuka@jpower.co.jp 3Honorary Member of JSCE, Professor, Kyushu University (744 Motooka, Nish-ku, Fukuoka 819-0395, Japan) E-mail: kusuda@kyudai.jp
Energy Losses in Storm Drain Access Holes
This article reports on a re-analysis of a Federal Highway Administration (FHWA) study from 1986-1992 of energy losses through storm drain access holes (junction holes), using relatively large-scale physical models. The new analysis separated the 1986 - 1992 data into two groups: base runs with the simplest configurations (one inflow and one outflow pipe with the same base elevations); the second group included the more complex configurations used to derive adjustments to the first approximations. The new analyses were undertaken to evaluate the proposed procedure and to characterize the energy level in an access hole with various inflow and outflow pipe configurations. The authors note that characterizing energy in the access hole is highly problematic because the flow is so chaotic, and arbitrary assumptions have to be made to obtain results that fall between intuitive limits. The authors conclude that the proposed new methodology addresses the problem of super-critical flows in outflow pipes. The use of inlet control culvert equations to estimate the initial depth in the access hole for these situations appears to also work well. In addition, the new technology allows use of much smaller scale models while maintaining (or improving) the accuracy of results, and allowing testing of different configurations and junction types.
Early Cretaceous Feathers from Victoria
Unusually well preserved fossil feathers from Lower Cretaceous (VaIanginian-Aptian) claystones at Koonwarra, Victoria, are the oldest (c. 110-125 million years) bird remains yet found in the southern hemisphere, They are among the oldest bird remains known in the world, being antedated only by the toothed Archaeopteryx from the late Jurassic of Bavaria, and being more or less the same age as Gallornis from the Lower Cretaceous of France. The Victorian fossil feathers are evidence for essentially worldwide distribution of birds soon after the beginning of the Cretaceous, if not before. The feathers could conceivably have come from toothed birds.