Meandering river modeling

RE: Meandering river modeling

2018-04-29T04:43:04Z

Hi Liang,

I recommend checking the model hydraulics (are you getting the desired flows and velocities, do shear stresses vary across the width of the channel), if the hydraulics are ok then check the sediment transport (is transport occurring, what is the transport rate through cross-sections at different locations alongthe channel, have you got sediment entering the model at the upstream boundary, does the pattern of transport look sensible). Finally, once you are sure that the model hydraulics and sediment transport are performing well, I would look to how the morphology is evolving (are there areas of erosion/deposition, do the patterns match what you expect, is there any bank erosion occuring). Checking the model in this logical manner usually reveals what the problem is.

Using quickplot to analyse the trih and trim files it should be relatively easy to work through these checks. Let us know how you get on...

Cheers,

Richard

RE: Meandering river modeling

2018-04-27T11:36:00Z

Hi Richard,

Thanks a lot for your reply. I have activated the process of secondary flow (and set a initial condition of secondary flow with 3 m/s) and set the MorFac to 100. But the model still does not work. Is there any other reason for non - lateral migration?

Cheers,

Liang

RE: Meandering river modeling

2018-04-27T04:35:58Z

Hi,

I had a quick look at you model. One reason you have no morphological change in your model is that the Morphological scale factor (MorFac) is set to zero. You should set MorFac = 1 to have morphological changes simulated in your model (or MorFac > 1 if you want to accelerate morphological adjustment with respect to model hydraulics).

I also noticed that you have a single layer (i.e. 2D) model but you do not have secondary flow enabled. Secondary flow is an important process driving transverse sediment movement in meandering rivers. It can be explicitly modelled in 3D domains but in a 2D model it requires parameterization, this functionality is available in Delft3D by turning secondary currents on.

Good luck,

Richard

Meandering river modeling

2018-04-26T16:12:04Z

Hi everyone! Recently I am trying to model a meandering river, but the channel has no lateral erosion and migration. I do not know the reason. I attached my data below, waiting for any hint.