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Supercritical Lateral Outflow IAHR 2009 Conference Proceeding Paper in [pdf] Purpose
Supercritical
channels present a number of design issues as the flow is readily
disturbed. Yet, the design of
supercritical channels for storm water drainage is necessary in steep
environments. Storm drains flowing
into supercritical channels are typically aligned to minimize the angle
between the drain and the channel. By
doing so, standing waves are minimized.
Channels are often designed with additional freeboard downstream to
accommodate the standing wave. In contrast, flow
can be removed from channels via storm drain pipes for the purpose of Best
Management Practices consisting of storm water cleaning such as debris
removal and/or natural filtration. We
will present a number of physical models showing that channels flowing near
design capacity are not adversely affected by lateral outflow. However, in the same channels, low to
moderate flows with lateral outflow result in a rooster tail wave in the
channel. In this study,
various lateral outflows from supercritical channels are tested to assist in
determining design guidance with respect to:
angle of lateral outflow, guiding vanes, and ratio of outflow to
channel flow.
Physical model for the 45 degree angled outlet The backwater due
to the vane can be ignorable. With
this vane dimension of the model, the backwater does not affect to the
upstream boundary of the numerical domain.
Time dependent x-directional velocity is shown with colored surface
plot and streamlines in the figure shown as below.
CFD simulation results 45 degree lateral outlet with tapered vane South Diversion Channel Modeling
Study
El Bordo Siphon Draft numerical modeling note in [pdf]
Junction Box Plan View
and longitudinal section view (see the construction plan sheet 7/8) With the current
junction box design, flow will be delivered safely. After approximately 40
seconds, the box outlet flow rate (300 cfs) is getting stable (see the plot
below). Very high velocity (12 ft/s) was simulated under the 5’ DIP (red
colored region in the figure below). See the time series simulation results
(3‐D view). However, the inlet boundary condition (6 ft/s velocity with
fully filled flow area) is an imaginary condition. Design flow rate and
velocity are needed. Flow retention
due to the junction box is expected. To test backwater impact to upstream,
the numerical model domain (8’ RCP part) needs to extend.
Field Temperature Assessment for Artificial Turf Alternation Full modeling report in
[pdf] Purpose and Backgrounds
The Albuquerque Metropolitan Arroyo Flood
Control Authority (AMAFCA) and Bernalillo County are exploring the
possibilities of playing fields made of artificial turf rather than natural grass, specifically as
they might be located in detention ponds. The University of New Mexico carried out a
previous experiment demonstrating the highly buoyant nature of the artificial turf.
Research during that experiment raised concerns about the increased air temperatures above
artificial turf. The Paradise Hills Community Complex
consists of baseball and soccer fields. Baseball fields one and two have infields and
outfields of natural grass, field three has an infield of artificial turf and an outfield of natural
grass. Artificial turf is growing in popularity in arid and semi-arid regions as demands on
water resources increase. The purpose of this experiment is to study the differences in
air temperature above natural grass and artificial turf.
Conclusion
Although artificial turf is appealing for
playing fields because of its low maintenance and water savings, there are other factors to
consider. Artificial turf is warmer than natural grass. Artificial turf makes for water savings in arid and
semi-arid environments, it is in these same environments that increased
temperatures would be a concern for young athletes.
It could be worthwhile to conduct a similar experiment where there is
a larger field of installed
artificial turf. South
Diversion Channel Modeling Study Objectives
The
objectives of this 1/30 scale model are:
1- Observe flow pattern around designed
Coanda-screen set-up,
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