Hello
I am having a problem regarding the sediment module of the hec ras 5 (LATEST VERSION) boundary condition SEDIMENT SERIES when simulated using the COMPLETE UNSTEADY MODULE of the model (not the quasi-steady).
I will try to explain the sediment load series working boundary condition working philosphy with the pictures below:
Link for pictures: https://1drv.ms/f/s!AuWGknWQxcr7hHZbTFk5BlkGoWnE
See Picture 1
Hopefully, the picture_1 is sufficient for the explanation.
Now, i defined a simple sediment time series, defined sediment load DURATION=24 hours to avoid any interpolation issues. Moreover, i only considered a single family of sediment particles for further simplification. See the picture link below:
See Picture 2
I ran a discharge of 3500 cusecs in the model and performed the quasi-state analysis first. The results are logical. The INCOMING MASS CUMM (tons) is exactly as i was expecting. The magnitudes are okay and the results are in accordance to the sediment load time series.
See Picture 3
Afterwards, i kept the same boundary condition and head dsicahrge and performed the same analysis but ysing the UNSTEADY MODULE with SEDIMENT OPTION checked. The MASS CUMM (TONS) is illogical in this case and the results are not in accordance to the sediment load series boundary condition.
See Picture 4
I believe i have analyzed this problem by every angle but i do not have any explanation regarding the results produced by the model after triggering the unsteady module. They do not follow the sediment load series boundary condition and the time duration and the magnitudes are bizzare. The only explanation i have is that the model has some sort of bug but i am not sure of it. May be i am doing something wrong. I have sent the same problem to the HEC guys and am waiting for their comments but i would appreciate if anyone here on the forum could have a look and point out problem that he/she feels is the reason for such results. Looking forward to your feedbacks.
Regards
Nayyar Minhaj Asif