User Forum of Software BASEMENT

huangvy

User

Registered: 2015-07-23

Posts: 24

Modelling longitudinal fining experiment

Dear all,
       I have tried to model the downstream fining experiment carried out by Paola et al. (1992, Downstream Fining by Selective Deposition in a Laboratory Flume. Science, pp.1757-1760 ). The results seemed strange in the cross section of feeding. It deposited very high and thus formed a sharp bed profile. In the last two weeks I have tried to change parameters such as bedload factor, control volume thickness, theta_critical and the bedload transport formula. However, the problem existed. Is there anyone who knows how to solve this problem or given some suggestion? By the way the software version is 2.5.3. 

Best wishes,

Wei

Matteo Facchini

Developer

From: Trento

Registered: 2014-09-05

Posts: 281

Re: Modelling longitudinal fining experiment

Hi Wei,
thanks for your post.
How many grain classes are you using? Which transport formulas did you use?
If I recall it correctly, in that paper Paola et al. used a bimodal grain size distribution, with a good percentage of sand. In that case, you could wait until the next release where the Wilcock and Crowe formula will be implemented, and that could help you simulating these experiments.
Cheers,
Matteo

huangvy

User

Registered: 2015-07-23

Posts: 24

Re: Modelling longitudinal fining experiment

Hi Matteo,
Thanks for your reply. I used 18 grain classes in the simulation. I have tried both the Wu's formula and the Multi_MPM formula, but the results seems having the same problem. The Wu's formula should be capable of modeling this case  since it has been proved by Wu et al. (2004) and Qian et al. (2015, International Journal of Sediment Research 30(2) ). By the way, when can I get the next version?

Best regards,

Wei HUANG

Matteo Facchini

Developer

From: Trento

Registered: 2014-09-05

Posts: 281

Re: Modelling longitudinal fining experiment

Hi
I suggest you to try the parker formula and to change your boundary conditions, both hydraulics and sediment. Which one are you using, by the way?
Cheers,
Matteo

huangvy

User

Registered: 2015-07-23

Posts: 24

Re: Modelling longitudinal fining experiment

Hi
I suggest you to try the parker formula and to change your boundary conditions, both hydraulics and sediment. Which one are you using, by the way?
Cheers,
Matteo

Hello
I had tried to use parker formula, however, the unrealistic high deposition at the feeding point, and thus a sharp bed profile, was still shown. I am not understanding your suggestion about changing the boundary conditions,  since the boundary conditions were obtained from the experiment. Moreover, did you have reproduced the experiment?

Best regards,
Wei

Matteo Facchini

Developer

From: Trento

Registered: 2014-09-05

Posts: 281

Re: Modelling longitudinal fining experiment

No, I never reproduced those experiments.
With changing the boundary conditions I mean changing them in BASEMENT while keeping them the same as in the experiment (e.g. using hqrelation instead of zero_gradient but still reproducing the same effect...)