Hello,
I have to set up 1D/2D model in hecras. I first set up the 1D network and simulated it and it simulated without an error. Then I wanted to connect it with 2D area. Initially I installed bit lengthy lateral structure to connect 1D and 2D areas and end up with an error(high EG at certain CSs). So I thought to install few structures instead of one and once I installed the first structure model simulated without any issue (WSL error was there but in acceptable margin). Once I going to install the lateral structures in other locations, it become unstable in the halfway (give me very high EG at certain CSs). I have tried several times.
I have used Diffusion Wave method
– Have set 1D/2D iteration to 20 (for 2D 20)
– for the structure: Normal 2D equation (Cd=1 SI Units)
– I have set 2D initial condition so that 1D/2D connection does not go under dry condition at the beginning of the simulation.
Any advise to get rid of this?
Did you try setting the lateral structure to use the 2D Equations?
A value of 1 could be too high of coefficent value. If you look at the user’s manual (page 3-50), a value of 1 would be if you had a levee/roadway that is elevated. If it is just natural ground, .11 to .55 in SIS units would be more appropriate.
Thanks for the reply Cameron..!
yes. I used 2D equation. I tried with Cd maximum, minimum and mid level coefficient.
Further I have introduced intermittent CS s whether slope is steep but yet my model crashes giving me high EG values in some of the CSs. So it is still unsolved.
I think still I am not familiar with the art of finding the errors in HEC-RAS 1D/2D models…!