Sunday, August 30, 2015
Advanced Force Network Support in InfoSewer for Steady State and EPS
The Advanced Force Network Support allows the simulation of multiple upstream and downstream force mains entering and leaving one chamber junction during an Extended Period Dynamic Simulation or EPS solution in Sewer. All of the force mains, pumps, wet wells and force main chamber junctions that are connected are considered as one force main network in the EPS and steady state solution. You can have more than one force main network in a large Sewer model separated by gravity pipes and loading manholes. The individual force main networks are solved iteratively with different upstream head and downstream tail manholes which connect the force main network(s) to the rest of the network.
A force main network consists of the following elements:
· Wet well
· Junction Chamber
· Head Manhole where flow from other parts of the sewer system enters the force main network or loading manhole
The head and tail manhole for one force main network is determined by the program based on the geometry of the network. The force main network starts at a wet well, includes the pumps connecting the wet well to the force main links and also includes the actual force main links and force main connecting junction chambers. You can also connect a force main to the gravity mains without an intermediate wet well and pump(s).
The boundary conditions of the force main network are:
· Water heads at the wet wells which vary according to the inflow from the upstream sections of the sewer network and outflow to the force main network
· Water head at the tail manholes which are calculated as the maximum discharge head (invert + diameter) of all the force mains that end at that manhole. Water entering the tail manholes will be routed downstream after the force main network flows are calculated.
For example, assuming there are n1 wet wells, n2 head manholes, n3 tail manholes, n4 junction chambers and l1 pumps and l2 force mains, the program must solve the network hydraulics to get n2+n4 water head values and l1+l2 flow values iteratively using the Newton-Raphson method. The solution iterates until the mass and energy of the force main network is in balance.
The hydraulic equations used in the solution are:
· Head/Flow relationship of the force mains and pumps (l1+l2 equations)
· Mass balance at head nodes and junction chambers (n2+n4 equations)
For head nodes, water entering the network from other sections of the sewer system must equal the flow sum of force mains that connect to it:
Where Q = Flow; Gv = group of gravity pipes connecting to the head manhole; and Gf = group of force mains connecting to the head manhole. The sum of the gravity flow into the wet well or head manholes is balanced by the sum or flow out of the force main network in the force main pipes.
For junction chambers, which are connected to only force main pipes:
For force mains, Hazen-Williams equation describes the flow/head loss relationship within a force main. The flow out of and the flow into the junction chamber is in balance. The head at the junction manhole is iterated until the flows are in balance.
For pumps that are neither Inflow Control nor Discharge Control, the pump curve is used to estimate the flow and head gain relationship within a pump. For Inflow Control and Discharge Control pump, pump flow as control values are fixed and the equation Q = Qcontrol, where Qcontrol is the controlling pump value. For such situations, the pump is actually modeled as variable speed pump and pump speed will be calculated with Newton-Raphson method to achieve the flow control objective.
Note: The minimum travel distance in an InfoSewer or H2OMap Sewer model can be related to the mean link length in the Pipe DB Table. Here is a table of the Mass balance check for one network versus the minimum travel distance in feet for the default values of network accuracy, minimum time length and maximum number of segments at a report time step of 1 hour. As you can see making the Minimum Travel equal to the mode of the length histogram yields the best results even for the default model parameters.
|Minimum Travel Distance||Mass Balance Check:||Label|
Friday, August 28, 2015
Subject: How to Make a SWMM 5 Calibration File from InfoSWMM
1st Step: Graph a Link in InfoSWMM using the Date /Time Format
2nd Step: Click on the Report Button and copy the 1st two columns of data
3rd Step: Save the copied columns to a data file, replace the semi colon and add the name of the link to the top of the data file as shown below
4th Step: Connect the created calibration data file t o the SWMM 5 Calibration Data Link Flow Rate
5th Step: Run the Simulation and you should see two graphs on the screen for the designated link
Thursday, August 27, 2015
Note: How to Use the Arc Map Editor in InfoSWMM
Step 1 is to use the Edit Feature for example the Subcatchment layer to bring up the Arc Map Editor Tool.
Step 2 is to use the Reshape Feature tool or Vertex tools to bring together mis matched Subcatchment Boundaries
Step 3 is to use save the edits and then Update the DB from the Map to recalculate the area of the Subcatchments
Subject: InfoSWMM and Arc GIS for Create Graphs Using Network Data and Model Results
An important advantage of using InfoSWMM is the ability to use all of the Arc GIS layer and programming tools. For example, you can graph the model results in Bar, Pie, Scatter, Bubble or other types of Graphs once the model data and model result layers are Joined together. The image below shows a thematic mapping for Node Flooding, Conduit Force Main Type and a Pie and Bar Chart of Node Flooding Time and the Q Full in the links, respectively.
The Structure of InfoSWMM in Arc Map
Subject: InfoSWMM and Arc GIS Layer Properties for Surcharge and Flooded Time
An important advantage of using InfoSWMM is the ability to use all of the Arc GIS layer and programming tools. For example, you can graph the model results for the flooded and surcharged time in a node using a Bar/Column plot to show the surcharge time in the node and the flooded time in the node. A flooded node is always considered to be surcharged but a surcharged node does not always flood. The surcharge level is any water surface elevation above the highest connecting crown elevation but the flooded time is a water surface elevation at or exceeded the rim elevation of the node.
Sunday, August 23, 2015
Thursday, August 20, 2015
------------------------ Build 5.1.010 (08/05/15) ------------------------- Source Engine Updates: 1. A modified version of Green-Ampt infiltration (MODIFIED GREEN AMPT) was added that no longer redistributes upper zone moisture deficit during low rainfall events. The original authors of SWMM's Green-Ampt model have endorsed this modified version. It will produce more infiltration for storm events that begin with low rainfall intensities, such as the SCS design storm distributions. 2. A new type of weir, a ROADWAY weir, has been added. It models roadway overtopping using the FHWA HDS-5 method and would typically be used in parallel with a culvert conduit. 3. Rule premises can now test whether a link has been open (or closed) for a specific period of time. See the Help file for more details. 4. Unsaturated hydraulic conductivity ("K") was added to the list of variables that can be used in a user-supplied groundwater flow equation. 5. A bug introduced in update 2 of release 5.1.008 that failed to include infiltration from LID units into the groundwater routine was fixed. 6. A bug that failed to properly initialize the flag indicating that one or more LID controls was initially wet was fixed. 7. Duplicate printing of the first line of an LID detailed report file was corrected. 8. The Hargreaves evaporation formula was modified to use a 7-day running average of daily temperatures, instead of just single day values, as recommended by the formula's authors. 9. Daily potential evapotranspiration (PET) was added as a system output variable. 10. The qualrout.c module was refactored to make it more compact and easier to follow. 11. Storage seepage and evaporation losses are now based on the storage volume at the end, not the start, of the prior time step. 12. The command line used to build the engine included in the "makefile" for the GNU C/C++ compiler was corrected to include the OpenMP libraries.
Wednesday, August 12, 2015
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