Gravitational transport

Stefano · 2024-10-04 09:55:50

Hi to you all,

I've read all topics related to sediment trasnsport exposed in this forum over the years, but I cannot avoid sediment impiling in the inlet region.
Gravitational transport doesn't work though I try to vary values af angles and CFL and/or implemented different regions for water and sediment inlet, or with nodes inlet instead of entire region.
I tried to work in conjinction with a inlet boundary "capacity transport" but nothing to do: gravitational transport doesn't start.
Below I insert text of model.json.
Please, someone could find where/what is my mistake(s)?
Thanks, cheers

Stefano

{
"SETUP": {
"BASEMD": {
"BASEPLANE_2D": [
{
"GEOMETRY": {
"file": "C:/Users/Geologia/OneDrive - STUDIO ASSOCIATO GEOLOGIA TECNICA/Stefano/Tesero/BASEMENT/SOLIDO/1/BASE_NEW_computational-mesh.2dm",
"type": "2dm",
"STRINGDEF": [
{
"name": "inflow",
"node_ids": [
193,
356,
357,
358
],
"upstream_direction": "left"
},
{
"name": "outflow",
"node_ids": [
291,
198,
355,
802,
801
],
"upstream_direction": "left"
}
]
},
"HYDRAULICS": {
"FRICTION": {
"default_friction": 30.0,
"type": "strickler",
"wall_friction": "off",
"input_type": "index_table",
"index": [
1,
2,
3,
4,
5,
6
],
"friction": [
25.0,
25.0,
70.0,
70.0,
40.0,
20
]
},
"INITIAL": {
"type": "index_table",
"index": [
1,
2,
3,
4,
5,
6
],
"h": [
0.05,
0.0,
0.0,
0.0,
0.0,
0.0
],
"u": [
0.01,
0.0,
0.0,
0.0,
0.0,
0.0
],
"v": [
0.01,
0.0,
0.0,
0.0,
0.0,
0.0
]
},
"PARAMETER": {
"simulation_scheme": "exp",
"riemann_solver": "exact",
"minimum_water_depth": 0.05,
"dynamic_depth_solver_precision": 0.005,
"dynamic_depth_solver": "on",
"geo_max_angle_quadrilateral": 45,
"velocity_update_partial": "volume_area",
"riemann_tolerance": 1e-06
},
"BOUNDARY": [
{
"type": "hqrelation",
"string_name": "outflow",
"slope": 1.0,
"dynamic_slope": "no",
"conveyance_type": "tables",
"wall_flux": "no",
"weighting_type": "conveyance",
"wse_calc_method": "average"
}
],
"SOURCE": {
"EXTERNAL_SOURCE": [
{
"type": "source_discharge",
"file": "C:/Users/Geologia/OneDrive - STUDIO ASSOCIATO GEOLOGIA TECNICA/Stefano/Tesero/BASEMENT/SOLIDO/1/portata_liquida.txt",
"index": [
1
]
}
]
}
},
"region_name": "RIO_STAVA",
"OUTPUT": {
"console_time_step": 300.0,
"SPECIAL_OUTPUT": [
{
"output_time_step": 120.0,
"type": "BASEviz",
"variable": "depth"
},
{
"output_time_step": 300.0,
"type": "node_centered",
"format": "ascii",
"values": [
{
"accumulator": "max",
"value": "depth"
},
{
"accumulator": "max",
"value": "wse"
},
{
"accumulator": "max",
"value": "abs_velocity"
},
{
"accumulator": "max",
"value": "abs_momentum"
}
]
},
{
"output_time_step": 300.0,
"type": "node_centered",
"format": "ascii",
"values": [
{
"accumulator": "max",
"value": "sediment_sum"
},
{
"accumulator": "max",
"value": "deltaz"
}
]
},
{
"output_time_step": 300.0,
"type": "boundary_history",
"boundary_values": [
{
"value": "Q",
"accumulator": "none"
},
{
"value": "Qsed",
"accumulator": "none"
}
],
"history_one_file": "yes"
}
]
},
"MORPHOLOGY": {
"BEDMATERIAL": {
"GRAIN_CLASS": {
"diameters": [
105.0
]
},
"MIXTURE": [
{
"name": "UNICO",
"volume_fraction": [
100.0
]
}
],
"SOIL_ASSIGNMENT": {
"index": [
1,
2,
3,
4,
5,
6
],
"soil": [
"INLET",
"ALVEO",
"FIXED_BED",
"FIXED_BED",
"VERSANTE",
"SPONDA_NUDA"
]
},
"SOIL_DEF": [
{
"name": "INLET",
"LAYER": [
{
"bottom_elevation": -1.0,
"mixture": "UNICO"
}
],
"tau_erosion_start": -1
},
{
"name": "ALVEO",
"LAYER": [
{
"bottom_elevation": -0.5,
"mixture": "UNICO"
}
],
"tau_erosion_start": -1
},
{
"name": "VERSANTE",
"LAYER": [
{
"bottom_elevation": -10.0,
"mixture": "UNICO"
}
],
"tau_erosion_start": -1
},
{
"name": "SPONDA_NUDA",
"LAYER": [
{
"bottom_elevation": -4.0,
"mixture": "UNICO"
}
],
"tau_erosion_start": -1
},
{
"name": "FIXED_BED"
}
]
},
"INITIAL": {
"type": "initial_mesh"
},
"PARAMETER": {
"porosity": 37,
"density": 2000.0,
"control_volume_type": "constant",
"control_volume_thickness": [
0.05,
0.05,
0.05,
0.05,
0.05,
0.05,
0.05
],
"control_volume_thickness_index": [
1,
2,
3,
4,
5,
6,
7
],
"control_volume_initial": "soildef",
"local_slope_angle_repose": 30
},
"BEDLOAD": {
"FORMULA": {
"bedload_formula": "smartjaeggi",
"local_slope_correction": "local_slope_vanrijn",
"critical_shear_stress_calibration": 1,
"d30": 60.0,
"d90": 230.0,
"theta_critical": [
0.05,
0.05,
0.05,
0.05,
0.05,
0.05
],
"theta_critical_index": [
1,
2,
3,
4,
5,
6
]
},
"PARAMETER": {
"bedload_routing_start": 0.0,
"limit_bedload_wetted": "on",
"use_cell_averaged_bedload_flux": "off",
"use_real_edge_lengths": "off"
},
"BOUNDARY": [
{
"string_name": "outflow",
"type": "IODown",
"fraction_boundary": 0.9
}
],
"DIRECTION": [
{
"lateral_index": [
2
],
"lateral_transport_type": "lateral_bed_slope",
"lateral_transport_factor": 1.5
}
]
},
"SOURCE": {
"EXTERNAL_SOURCE": [
{
"type": "sediment_discharge",
"file": "C:/Users/Geologia/OneDrive - STUDIO ASSOCIATO GEOLOGIA TECNICA/Stefano/Tesero/BASEMENT/SOLIDO/1/portata_solida.txt",
"mixture": "UNICO",
"index": [
1
]
}
]
},
"GRAVITATIONAL_TRANSPORT": {
"angle_failure_deposited": [
10.0
],
"angle_failure_dry": [
40.0
],
"angle_failure_wetted": [
15.0
],
"index": [
1
],
"angle_wetted_criterion": "partially_wetted",
"gravity_transport_on_cells": "all",
"max_delta_z": 0.001,
"max_iterations": 10,
"min_changed_volume": 0.01,
"cycle_step": 5,
"stabilization_height": 0
}
},
"TIMESTEP": {
"total_run_time": 84900.0,
"CFL": 0.1,
"start_time": -1,
"initial_time_step": 1
}
}
],
"multiregion": "RIO_STAVA",
"PHYSICAL_PROPERTIES": {
"gravity": 9.81,
"viscosity": 1e-06,
"rho_fluid": 1000
}
},
"simulation_name": "SOLIDO_200"
}
}

Lukas Vonwiller · 2024-10-04 10:42:18

Hi Stefano

Maybe some thoughts you could try:

- Try to run a purely hydraulic model first. I would prefer a inflow boundary to a source (your inflow boundary string looks small or maybe you have a coarse mesh)
- use your hydraulic model to create good initial conditions for your bedload transport model.
- add morphology block with bedload transport. Try to add bedload using a boundary condition.
- Your control_volume_thickness is a little bit small, try larger values, e.g. 1-3 times d90.
- For the grav. transport, you might start with the same values for dry, wetted and deposited angles (e.g. 30)

I hope this helps!
Cheers, Lukas

Stefano · 2024-10-08 11:56:40

Hi Lukas,

thank you so much for your kind response.
Excuse me to be in late by I needed to apply and verify your suggestions before writing.
I think I've detected the real cause of my problems: lateral friction along stream banks, 'cos I'm working on a mountain stream flushing between two steep - but not vertical - stone walls.
It seems that sediment stard depositing on face wall, rapidly increasing both vertically and laterally: after a while it forms a kind of earth dam across the entire stream section.
So I activated gravitational transport even for stream bank (via MATID) and now simulation seems to progress reasonably, at least.

Again, many thanks to you

cheers, Stefano

User Forum of Software BASEMENT

#1 2024-10-04 09:55:50

Gravitational transport

#2 2024-10-04 10:42:18

Re: Gravitational transport

#3 2024-10-08 11:56:40

Re: Gravitational transport

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