Adding Piers to a 2D HEC-RAS Terrain and Mesh

so I'm building a 2d Ras model and I've gotten to the point where I've got this bridge where I have to add these Piers these peers really affect the hydrodynamics through this bridge and the sediment transport and so I'm going to have to add them to the model we can turn on the map here you can see where the bridge is but if you know I turn that off and the the piers aren't stamped into the train and so I need to get them there I need to add the Pierce to the train and then I actually have to do another pretty important thing is it's not enough to just stamp the piers into the train I actually also have to make the mesh accommodate them and so that's what we're going to do I'm just going to show you like a couple steps about how I did this um so the first thing you need to do is you need to clone your terrain this is kind of cool because you don't actually have to make a full copy of the train and fill up your drive you actually just need to clone it and what it'll do is it'll point to the original terrain but then it'll keep track of the changes you made so we're going to right click on this 2013 lidar and we're going to say close own terrain and I'm going to call this peer demo and there we go now we have a cloned terrain and so I'm going to turn this one off I'm going to turn this one on and it comes with modifications now there's no modifications in there that's just a bucket for the modifications but we're going to modify this by adding Pairs and so what you'll see is I I just kind of digitized the location of these Piers I just added these profile lines so I'd know where they go and um so I'm going to go to modifications and I'm going to click on it and I'm gonna I'm gonna edit the layer and then I'm going to add modification and I'm going to go to shapes now there's lots of things you can do here um I I actually am going to do another video on how to do weirds and structures and rebasins with these you can also go and you can cut Channels with these These are incredibly powerful um but we're just going to go to elongated pier and I'll just call this peers that's great and you'll see it gives me this little generic beer right here and uh that is not the pier that I want those are not the peers that you're looking for but I'm gonna drop it anyways and I'm gonna get this editor now and that's going to let me modify this peer kind of in place and so um the first question is do you want to replace the terrain value yeah we're just going to stamp this in so that when you know Raz sees the train it sees this as the highest point the elevation is actually this is a coastal system so the bottom of the bridge bridge is actually 45 feet we're going to rotate this 65 degrees how do I know that because I measured beforehand trial and error is another way you could do that and then this is seven feet wide and then I actually want my peer to have um sharp noses because that's what it has in the field and in each case the the sharp nose is five which is just going to give it a triangle at the end and the length of these noses are 45. okay and so if I say okay it stand it stamps the here you know exactly where I put it rotates it and you can move this around but that's where this pier is going to go but then the next thing it does it says Hey chances are if this is a pure you're going to want more than one of these and so it gives me this template and so I can actually just move this around and stamp it wherever I want else I want it to be and so I know I want another one right here so boom I'm going to stamp it right there it says hey what's this well we'll call it Pier two that sounds great and I'll say okay and then I have my peers and I can keep stamping peers as long as I want but this bridge only has two so that's all we need so we're going to come here and we're going to say stop editing if you want to save edits to modifications yes I do and then if I plot the train profile you'll see that we actually have two peers in our in our Bridge profile we are ready to go okay so we got peers we should run right no not yet because we have peers in our terrain but we have to accommodate them in our grid and so now I'm going to go out back up to my geometry and I'm going to make a new geometry I'm going to save geometry as and I'll call this pure demo and of course um we'll go into our geometry associations and we'll manage our association so uh the pure demo geometry well that's going to be with the pure demo terrain which is really just the base lidar with these pure modifications that we've made right and so if I turn that on you'll see that you know what what is going to happen if we run this well it's not going to see the full it's not going to get the full force of those peers at least we have a center line so you know it's not like the pier is in the middle of the cell and you're going to kind of miss that effect you're going to miss that cloud but I still want to represent these peers in the mesh in a more realistic way and so the way I'm going to do that is I'm going to go in and I'm going to create a refinement region for the pier itself now this gets a little bit tricky and so I'm going to go in to 2D flow areas I'm going to start editing the refinement region and so now I'm just going to draw a refinement region that basically follows this peer and so if I can get my cells to follow that and if I can make more importantly if I can get myself faces to follow that it will completely include this area from my model and so I'm going to call this pr1 okay and so then I'm going to right click on it and I'm going to enforce my region and how did that go well that went poorly um I'm not sure that that's a lot better than it was um we did get cells that kind of filled this Center area I'm actually going to go in and I'm going to change my refinement region properties these cells are you know they're they're 10 to 10 to 15 foot cells and uh this pier you know it's seven feet wide and so that we got about six there so I'm actually going to go in and say you know my my refinement region is actually going to be six by six um then I'm going to check this enforcement off and if I come in here and I enforce all regions actually get a pretty nice fit but it's not going to be perfect you know as with a lot of mesh editing there's a lot of manual editing that happens um in order to get things the way you want them so we're going to move these around a little bit so that we get the pier that we want but you know this is not terrible um I don't really like the way that nose is is uh is coming out and so I'm going to move this around to try to capture the nose in order to do that maybe I'll drop one here and one here and that'll give me a better um a better run up to the nose and there you go so that uh that drops better and so there's just a little bit of manual work you have to do here but before long what you have is a mesh that actually you know tracks the modification itself and so it represents the the modification that you've made in not only in the train but also along the cell faces so that the subgrid can see that hey this is there nothing's going to go through it it's not actually sharing um cells substantially with the seclusion um and uh so then if you go in and model it you'll see that we're getting increased velocities through the bridge because of the occlusion of the piers and you know this pier that has the center line through it um it's it's not performing poorly you know you are getting flow split around that but there is some confusion going on about what's happening at the nose of the pier whereas the the pair we just did you know you're getting a kind of a better flow split around it and you know a better flow Shadow my name is Stanford Gibson I'm the settlement special list on the HC Ras team and this video was funded by the hhc set program

Channel: Stanford Gibson

Views: 4,031

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Id: 7xzwa3KSpJc

Length: 8min 28sec (508 seconds)

Published: Tue Aug 30 2022