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May. 29, 2012
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SWMM5 - Stormwater Management Model
SWMM 5, InfoSWMM, H20MAP SWMM, InfoSewer for Water Quality,Hydrology, Hydraulics
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Robert Dickinson commented on Robert Dickinson's group Stream of Information"by jasonkillinger. Browse more data visualizations.
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Robert Dickinson added a page to the group SWMM4 Input Files
Historical SWMM 5 and SWMM 4 Engines and Examples
Subject: Historical SWMM 5 and SWMM 4 Engines and Examples
The web site has http://swmm5legacycode.ning.com/ historical SWMM 5 installs, SWMM 5 input file examples and SWMM 4 input files and engines. The SWMM 4 engines go back to SWMM 3.5…
Robert Dickinson commented on Robert Dickinson's group SWMM4 Input Files"Subject: Historical SWMM 5 and SWMM 4 Engines and Examples
The web site has http://swmm5legacycode.ning.com/ historical SWMM 5 installs, SWMM 5 input file examples and SWMM 4 input files and engines. The SWMM…"
Robert Dickinson added a page to the group Blog Links
SWMM5.NET
15 GPM
1985
1D Components in InfoSWMM 2D
3 Types of Manholes in SWMM 5 and InfoSWMM
3 Types of Subcatchment Flow in SWMM 5
A Basic InfoSewer Wet Well
A feedback loop involves four distinct stages
A rise in Pipe Inverts Across a SWMM 5 Node
A…
Robert Dickinson commented on Robert Dickinson's group Stream of Information"Udaipur, India
May. 28, 2012
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Robert Dickinson commented on Robert Dickinson's group Weather"Man-made Pollution Shifting Tropics and Sub-Tropics Poleward
"If a poleward displacement of the mid-latitude storm tracks also occurs, this will shift mid-latitude precipitation poleward, impacting regional agriculture, economy, and…"
Robert Dickinson commented on Robert Dickinson's group Weather"Poor neighborhoods have fewer trees, as these jarring satellite photos reveal.: http://www.treehugger.com/economics/how-spot-income-inequality-space-look-trees.html"
Robert Dickinson commented on Robert Dickinson's group Weather"
Climate Change is Frying Our Cities
Rising temperatures are set triple the heat-related deaths in cities across the U.S., a new report finds. Cities need to fight back."
Robert Dickinson posted a videoRSA Animate - The Power of Networks
In this new RSA Animate, Manuel Lima, senior UX design lead at Microsoft Bing, explores the power of network visualisation to help navigate our complex moder...
Robert Dickinson commented on Robert Dickinson's group ExtraVariables"Update of May, 20012
Epaswmm5.exe
swmm5.dll"
Robert Dickinson replied to Robert Dickinson's discussion How is the St Venant Equation Solved for in the Dynamic Wave Solution of SWMM 5?"Subject: Link Iterations in the SWMM 5 Dynamic Wave Solution
Each of the links in the SWMM 5 network can use up to 8 iterations to reach convergence during a time step in the dynamic wave solution of SWMM 5. The rules…"
Robert Dickinson left a comment for wu ze jian"Hi, I added this discussion http://swmm2000.com/forum/topics/how-is-the-st-venant-equation-solved-for-in-the-dynamic-wave-solu"
Robert Dickinson posted a discussionHow is the St Venant Equation Solved for in the Dynamic Wave Solution of SWMM 5?
Subject: How is the St Venant Equation Solved for in the Dynamic Wave Solution of SWMM 5? An explanation of the four St. Venant Terms in SWMM 5 and how they change for Gravity Mains and Force Mains. The HGL is the water surface elevation in the upstream and downstream nodes of the link. The HGL for a full link goes from the pipe crown elevation up to the rim elevation of the node + the surcharge depth of the node. The four terms are: dq2 = Time Step * Awtd * (Head Downstream – Head Upstream)…See More
The Keep and Dampen options and their effect on the four main terms of the St Venant equation
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Note: The Keep and Dampen options and their effect on the four main terms of the St Venant equation.
The four terms are are used in the new flow for a time step of Qnew:
Qnew = (Qold – dq2 + dq3 + dq4) / ( 1 + dq1)
when the force main or gravity main is full dq3 and dq4 are zero and Qnew = (Qold – dq2) / ( 1 + dq1)
The dq4 term in dynamic.c uses the area upstream (a1) and area downstream (a2), the midpoint velocity, the sigma factor (a function of the link Froude number), the link length and the time step or
dq4 = Time Step * Velocity * Velocity * (a2 – a1) / Link Length * Sigma
where Sigma is a function of the Froude Number and the Keep, Dampen and Ignore Inertial Term Options. Keep sets Sigma to 1 always and Dampen set Sigma based on the Froude number, Ignore sets Sigma to 0 all of the time during the simulation
the dq3 term in dynamic.c uses the current midpoint area (a function of the midpoint depth), the sigma factor and the midpoint velocity.
dq3 = 2 * Velocity * ( Amid(current iteration) – Amid (last time step) * Sigma
dq1 = Time Step * RoughFactor / Rwtd^1.333 * |Velocity|
The weighted area (Awtd) is used in the dq2 term of the St. Venant equation:
dq2 = Time Step * Awtd * (Head Downstream – Head Upstream) / Link Length or
dq2 = Time Step * Awtd * (Head Downstream – Head Upstream) / Link Length
Normally, dq1 (Friction Loss / Maroon in the Graph) balances dq2 (Water Surface Slope Term or Green in the Graph) but often for links with a large difference between upstream and downstream depths dq4 (Red in the Graph) can have a significant value. If dq4 or dq3 are important then the depth of water to increases to pass the same flow using the Keep option over the Ignore. If you have a link with a Froude number near or over 1.0 (Supercritical) then using Keep or Dampen for the Options may result in depth differences. The effect of Keep is to increase the “loss” terms in the St Venant Equation. The effect of Dampen and Ignore is to decrease the sum of the “loss” terms in the St. Venant Solution and lower the simulated depth.
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