We have several buildings which we are seeking to harvest rainwater to an earth dam for use. Basically we have several gutters and downpipes. The Downpipes will in turn be connected to collection pipes which eventually flow into the earth dam. The water should basically flow into the earth dam through gravity. The objective here is to establish the furthest building we can collect water from and size the collection pipes accordingly.
So far I have done the following:
Am i in the right direction so far? Is WaterGEMS the right modelling solution?
I currently seem to have one problem though. Negative Junction Pressures, with reasonably high velocities, in areas where logically there shouldn't be none. Am i missing something.
Jesse Dringoli said:top set equal to the pipe top
What is this?
It means setting the rim elevation field in the manhole properties equal to the top of the actual enclosed structure. Meaning, if this represents a pipe junction with no actual vertical structure, then the top of the "junction" is the top of the pipe. If you must use a manhole (instead of the suggested transition element) then you would set the rim elevation (top of the structure) to the elevation of the top of the pipe, and choose the bolted cover option so that surcharging occurs if the HGL is above the rim.
Regards,
Jesse DringoliTechnical Support Manager, OpenFlowsBentley Communities Site AdministratorBentley Systems, Inc.
Have tried the two options, with GVF Rational, and need some clarifications.
Japheth Osumo said:Now since i already know the flows do i really need to draw the catchment areas accurately or i can simply have random shapes
Yes, you can hold the CTRL key and left click in the drawing to start drawing the default shape. Move your cursor and then click again to place. Select "None" as the runoff method in the catchment properties (or global edit in the catchment Flextable), then enter your fixed flow in the "Inflow (wet collection)" as a fixed flow. You can also use the Inflow Control Center (Components > Loading) to initialize and enter a fixed flow for all catchments, if needed.
Note that the Implicit and Explicit solver perform an unsteady simulation where the element of time is involved. This means that if you enter a constant flow, it will be the same flow value for all timesteps. So, you would want to make sure that the flow values you calculated are acceptable to assume as a constant flow rather than a hydrograph that rises up to a peak for a short period of time and then drops back down. Consider the amount of water volume from a constant flow and the impact it has on the hydraulics of an unsteady simulation.
Japheth Osumo said:Use of Manholes: There's Ground, Rim and Invert Elevations. Assuming my pipe will basically follow the ground surface (Invert= Ground Surface). What is the best way of populating these..
If you are modeling an enclosed junction of pipes (no vertical vault structure) and the pipes are resting on the ground, then the manhole invert and ground elevation would be equal to the ground and the rim elevation would be equal to the pipe top/crown.
To quickly populate the ground, you could use Terrain Extractor, and then copy/paste the ground elevation values to the invert elevation, using the Flextable: Copy and paste (import or export) tabular or Flextable data
If all pipes are the same diameter, you could also paste the ground elevation to the rim elevation field, then perform a global edit to globally add the pipe diameter/rise value. If there are varying conduit diameters, you would need to manually add the diameter of the adjacent conduit to the invert to get the rim elevation. You could perhaps use annotations to help with this.
Am getting somewhere. So basically i need to create like 1,000 catchments and associate them to Transition Elements. Any quick way of doing this, like in one or two clicks. Currently am going into the properties of each catchment and selecting the outflow element. For 1,000 catchments this can take a while. Looking for an option to simply select a catchment and click on a transition element, then the transition element gets tagged as the outflow element..