Comment: A method to model Mud flow and other Non Newtonian Fluids in a modified SWMM 5. You will have to modify the code as described in the link to actually model mud flow. Link Here
LPS Output Units when the Inflow is CMS
1. The inflow time series is in units of CMS,
2. If you set the internal units to LPS in Run Manager,
3. Set the output units to LPS in Output Unit Manager,
4. Add a Scale multiplier of 1000 in the Inflows DB Table then
The inflows do not have to be altered, the internal model flows will LPS, the velocity will be m/s with 6 decimal places in the RPT file and the flows will be LPS with 3 decimal places in the RPT file.
Opening and Closing an Orifice with a Time series Setting
The Three Flows in SWMM 5 for a Link
There are actually three flows computed or used for a link in SWMM 5:
1. The St. Venant Flow equation flow
2. The Upstream Normal Flow Manning’s equation based on the link roughness, slope, upstream cross sectional area and upstream hydraulic Radius,
3. The flow actually used in the model which is either the flow computed from St. Venant or Manning’s equation
The following three links shows how this works in a real model:
· Link 8040 almost always uses the St. Venant Equation because it is dominated by backwater and surcharge
· Link 8100 almost always uses Manning’s equation except at the beginning and end of the simulation,
· Link 1600 is an adverse slope link and it mainly uses the St. Venant equation.
· Flow = the flow actually used during the simulation
· Qdynamic = the flow computed from the St. Venant Equation
· QNormUp = Flow based on Manning's equation at the upstream end of the link.
· QNormDown = Flow based on Manning's equation at the downstream end of the link.
Link 8100 almost always uses Manning’s equation except at the beginning and end of the simulation. The beginning and end of the simulation is when the non linear terms dominant.
Orifice Open and Close Speed and the Target Setting
In SWMM 5 there is an orifice parameter called setting which opens or closes the orifice opening by modifying the depth of the orifice. The setting is based either on a RTC rule of the orifice or the Flap Gate condition of the orifice and can be between 0 and 1. Closed is 0; Open is 1. The difference is that the target setting is what the setting should be based on the condition of the Flap Gate or the RTC Rules and the setting is the value actually used in the model.
The open and close speed of the orifice modifies the orifice setting by changing the orifice setting based on the open and closing speed using the equation:
New Orifice Setting = Old Orifice Setting + (Target Setting – Orifice Setting) * Time Step / Orifice Open and Close Speed
If your target setting and the current orifice setting are both 1 or 0 then the orifice Open and Close option does not change the orifice setting. New Setting equals Old Setting in that case. If the target and setting are out of phase then the Open and Close Option will function correctly. For example, if the Open and Close Speed is 1 hour then the orifice setting will open and close in a one hour period. The table shown below shows how the orifice setting changes as a function of the speed and the difference between the target and orifice settings. The setting starts out open but the target says closed – the orifice then closes over a 1 hour period. At one hour the target setting is 1 and the orifice will then open over a one hour period.
Table - Link OR1@82309b-15009b
Setting Target
Days Hours
0 00:00:00 1.00 0.00
0 00:15:00 0.74 0.00
0 00:30:00 0.50 0.00
0 00:45:00 0.25 0.00
0 01:00:00 0.00 0.00
0 01:15:00 0.25 1.00
0 01:30:00 0.50 1.00
0 01:45:00 0.75 1.00
0 02:00:00 1.00 1.00
0 02:15:00 0.75 0.00
0 02:30:00 0.50 0.00
0 02:45:00 0.25 0.00
0 03:00:00 0.00 0.00
0 03:15:00 0.00 0.00
0 03:30:00 0.00 0.00
0 03:45:00 0.00 0.00
