AutoCAD Civil 3D :: Modeling Super Critical And Transitional Flow
Jan 9, 2013
I am modelling a steep channel of constant slope operating under super critical flow conditions between two small weirs. I have set up two different models to represent this:
1. A single link between the upstream and downstream weirs.
2. I have also modeled the channel as a number of smaller links with the same slope separated by nodes spaced arbitrarily along the channel length.
The two models give very different results. The former results in an unstable channel (oscillates between sub- and super critical flow) and a maximum velocity in the channel of around 1.5m/s. It seems to me that the velocity in the upper section of the channel should be higher. I assume this has something to do with the manner in which SSA averages the velocities along the entire channel link.
The second model gives more realistic velocities in the upper channel links (around 3.6m/s) and a hydraulic jump and transition to sub critical flow upstream of the weir in the lower channel. This seems more realistic. I think the trick here is to make sure that the downstream link is long enough to enable realistic formation of the hydraulic jump in the model.
I am having trouble getting my assembly to work in my corridor. I have a Basic Lane Transition subassembly with a Link Slope to Surface subassembly attached to it. The assembly follows my centerline alignment and the lane widens as designed out to my offset alignments. The slope grading to daylight works fine until the transitional lane starts to widen, then the slope assembly stays at the same point on the lane and does not stay linked to the end of the lane.
I am also having trouble getting the subassemblies to attach to the proper points. I keep trying different OSnaps unitl one seems to work, but I am never sure the subassemblies are connected properly.
I'm trying to model a cable. I do it with cylinder and EP Curve. I want to set an object motion and Object Flow Path.
I fallow also tutorial but still getting weird result.
My cylinder doesnt fallow the curve along. See attached img.
I set my motion object to normal...also the axis are set so the cylinder moves along curve on time slider good. But when I set Flow Path (latice) the object fallows the curve just with other end.
Superelevation curve criteria specifies axis of rotation but the assembly does not contain pivots.
okay i got this Before , just when i wanted to change in the Super Elevation Wizard , to outside lane rotation , i recently used AOR type , but yet no luck. also in my profile the super elevation the Cross slop Band : i always no matter what a rotation about center line.
I'm working on a runway in Civil 3D 2011. I want to transition cross slopes along the runway. i.e. 1.5% for sta 1+00 to 10+00 and then transition into 1.0%. I thought super elevation would be the best way to do this (I dont want any actual super elevation, just transitions in cross slope). When I select the alignment and "Calculate/Edit Superelevation" i get the following message in the commanding line:
"_AeccCalcEditSuperelevation No superelevation data has been calculated for the selected reference alignment." It does not bring up the wizard.
My runway alignment doesn't have any curves and I'm thinking that's the problem. Is is possible to create super elevation without curves?
I am using Civil 3d 2013 and I am trying to calculate the superelevation information in which the curve will max at 2%. Is there a way in which the superelevation can be calculated using the superelevation wizard in which a 2% SE is the max? So far it will only let me use the SE for 4% local roads and I have to edit it using the SE layout.
I have a superelevation on an alignment but want to remove this as its overriding the assembly I'm using. I have tried using the tabular editor within edit super elevation to remove the various sections but it's still not working. How can I remove the entire super elevation and revert back to my standard assemblys?
I want to know how exactly the super elevation within SAC works. I am building few SAs and some are just multi layered lanes and others are lanes with solder, etc.
How do I add super elevation to SA, After adding Super elevation to Parameter what is the next thing to do.
I have a client that wants to put in a constant flow into an inlet and have SSA calculate the HGL downstream of that (as well as add additional flows at additional inlets). Is there a way to do this? I tried adding an "Initial flow" to a pipe but after running the analysis, that flow wasn't the peak of the pipe (I used 1cfs for the initial flow and the peak was 0.77 cfs).
I need getting a roadway to transition horizontally for a turn lane. If it were straight without super, it would be easy. However, the transition happens in a curve that needs to be super elevated.
I know I can use the lane transition assembly and set it to "change offset and grade" but with that, I would have to manually calculate my EOP elevations.
Is there a sub assembly with the ability to use the centerline super elevation data as well as transition horizontally?
I have a section of road that has super elevation from -6% to +6%. The asphalt layer (top green) supers from -6 to +6 but the base course (red) only goes from -4 to +6. I attached a sketch for some visual information.
What subassembly recommended for this scenario?
Is there a way I can set max values for the subgrade? Or an assembly where I can use superelevation for the top and for the subgrade?
I am using C3D 2012 but can use 2013 if it makes a difference.
Civil 3D 2012 SP4.0 Windows 7 Enterprise 64-bit C3D 2014 SP1 Dell M6600, Core i7 @ 2.3GHz, 16 GB ram Dell T3500 workstation, too much ram
With Civil 2010 I used superelevataion to transition a street's cross fall from left to right. It was very straight forward with 2010.
Now with 2011 it appears that I cannot add superelevation to an alignment with any curve and change the crossfall of a street from left to right over 20m.
I am modeling an existing storm system that is under capacity. After running the model, some of the flows seem to be incorrect. I have one section that has a known flow of 1.31 cfs. The results for this pipe section shows 28.82 cfs (peak flow during analysis) and 6.06 cfs (design flow capacity). The pipe section is a 15" with constructed slope of 0.0088 ft/ft. The max velocity attained is 23.48 ft/sec. I know that the downstream is undersized. Could this flow rate be caused by the downstream backflows? The model is setup as hydrodynamic and rational method. My inertial terms are set at ignore, time step = 0, junction surface area = 0 and variable time step with safety factor 75%. I have gutter bypass flows and my sag structures have ponded area set at 100.
I received a drawing from another consultant that uses C3D 2013. When I open the drawing in C3D 2012 I get the message that it was created in a newer version of C3D so I assume he did a save as to 2010.
When I get drawings like this I copy what I need to the clipboard and paste into a new drawing (acad.dwt). This usually works fine. But in this case the drawing is almost 4 MB and contains just one arc. I purged everything I can from the drawing and it is still 3 MB.
I looked for but could not find any of the usual suspects: drawing scales, regapps, empty text objects and wipeouts. When I list "all" there is one arc in model space and 4 view ports in paper space. I did notice that there are hundreds of linetypes and text styles that cannot be purged.
I tried export to AutoCAD DWG 2010, 2007, 2004 and 2000 but that didn't work. Export to AutoCAD DWG R14 and DXF R12 both caused C3D to become unresponsive. Saveas to DWG R14 and DXF R12 caused C3D to become unresponsive.
I've got a highway project for which I'm modeling the corridor but the design profiles given to me are for the right lane top edge (ETW) and not the centerline (crown). This is an undivided planer roadway with a typical 2% cross-slope. How can I use that profile for the right edge to run my corridor? I can't seem to get the corridor to use the super table that is attached to the centerline when I use an offset assembly. Is an offset assembly the right way to go with this design?
What I've done just to get going is to take that right edge design profile and draw it in my centerline profile view, then lower it 0.24' (which is my 2% normal cross-slope for a 12' lane) and then use that as a centerline profile and let my normal super assembly and table data control the corridor through the supers. So far that is working--but is there a better way to do this?
We don not show CL profiles and only show the gutters on the CL profile view. We also do not used profile bands.
I need to show Superelevation on both left and right profiles complete with labeling.
Short of creating a seperate alignment for each, sampling the corridor surface, superimposing it onto the CL profile view and then creating a layout profile by drawing over the sampled surface.
Our provincial standard requires subgrade and subbase surfaces to have a normal cross slope of -3%. The base and asphalt surfaces have a normal cross slope for the driving lane of -2% and -5% for the shoulder.
I have been trying to figure out how to do this in C3D. I have thought of different ways of handling this for a straight tangent, but have not tested them. What is causing me the most grief at the moment is how to handle this in a curve with super elevation.
The transition will be different for -2%, -3% and -5% Runout distances.
Can C3D handle this? What about using Subassembly Composer?
(I should mention that I have tried with Subassembly Composer, but I am not sure how to deal with superelevation. -
As shown in the attached drawing, the station label where the superelevation transitions back into normal crown shows with 4 decimal places. We have verified that all precisions are set to 0.01ft. The normal crown station at the begin transition shows with 2 decimal places.
Civil 3D 2013 SP1 Dell T3500 Workstation Intel Xeon E5630 @ 2.53 GHz 12 Gig of RAM Nvidia Quadro FX3800 Window 7 x 64bit OS
Is there any reason why a corridor model would not be respecting the manually entered super elevation values in the alignment? I have several stations that should be calculated with even super elevation values, but they aren't. For example, at station 0+080 on my alignment the left crown should be running at -3%, but it is actually being calculated at -2.47%. It isn't just one station; it's most of them. No overridden stations, vertical targets, etc in the corridor. Just a fairly straight-forward align (hor/vert) with super, simple assembly (two lanes, shoulder, daylight), simple corridor.
where the setting is to reverse the flow of a pipe. I have the flow arrow shown in the wrong direction plus am showing a negative slope on a pipe, which should never be done.
I have a huge subdivision that we are about to do in civil 3d. The subdivision has over 1800 lots. I am wondering what is the best way to go about this. At the moment we are thinking we have to do the alignments, profiles and corridors all in one design drawing for it all to be dynamic? If so this file is going to be huge. Is there a way we can split it up and still keep everything dynamic?
I have a simple catchment area that I've routed to an inlet and then to an outfall. The 10 year storm peak flow going into the inlet is 3.91 cfs and my flow in the link to the outfall is 10.55 cfs. I do not understand why it is increasing going into the pipe. I've attached the pdf results here because for some reason it won't let me attach.spf file.
I am trying to figure out how big my pipes need to be for a storm sewer that I already have set elevations for. Every time I input the pipe and rim elevations for the network in the data tab it changes the inputs back to saying design. How do I set my own elevations for the pipe network?
I can't figure out how to reverse the flow direction on my pipe so I was going to just redraw it but after I delete a pipe and rt click to edit network the "add pipes and stuctures" won't let me add anything. I'm just guessing I need to reverse the flow direction because my invert out and invert in elevations are backwards in the profile. I'm working in Civil3D 2012.
