Lateral Coupling 1D-2D: Problem with steady-state simulation

Nils · 2022-11-16 17:38:22

Hi everyone

for my master thesis I´m trying to create a 1D-2D coupled model and got some problems and questions.

I´ve created the danube as 1D cross sections and the floodplain on the left danube side as 2D mesh.
The water enters and leaves the system only in the 1D subdomain.
(similar to BASEMENT Tutorial Nr. 6)

1. I ran my model to get steady-state conditions.
Until 154.900s I had mass loss, at 154.900s Input_Q was the same as Output_Q, after this time I got more Output_Q as Input_Q.
Now I´m wondering if there are steady-state conditions possible for my model, as I have some branches in my 2D mesh, where the water might take a long time to flow through?

2. I sometimes have small mass loss at some cross sections even before the 2D subdomain and at the coupling interface but without having branches etc... Is it normal for BASEMENT that the discharge Q rises and falls between the cross sections in very small amount? (xxxx.02 m³/s)

3. The help-Button in BASEMENT recommend for HYDRAULICS - BOUNDARY to use "coupling_hydrograph" and "coupling_hqrelation" instead of "hydrograph" and "hqrelation", but BASEMENT crashs when I try to use them. Is this because I don´t have a boundary for my 2D mesh?

4. Can someone maybe check my Input Structure, and if there are improvements to get shorter running times?
I have a huge floodplain, which I wanted to simulate as precisely as possible, but first tests gave me running times of more than 1 week (RTS < 0.5).

I really hope someone can help me, as I´m completely new to BASEMENT and hydrodynamic-numeric modelling.

Here is the output of the time 154.900 and underneath my BASEMENT structure:

time_s: 154900 time_step_s: 0.12803867852198891342
velocity_u_[m/s]: 1.5525291845234230337 wave_speed_c_[m/s]: 7.0390423498937231273 Element responsible for time step: 1907500
Edge_number Mass_Flux_[m3/s] Momentum_Flux_[m4/s2]    Total_Bedload_Flux_[m3/s]    Advective_Susp_Flux_[-]    Diffusive_Susp_Flux_[-]
0 1930 3086.01    0    0    0
1 1930 3091.71    0    0    0
2 1930 3153.63    0    0    0
3 1930 3162.89    0    0    0
4 1930 3329.69    0    0    0
5 1930.01    3310.91    0    0    0
6 1930.01    3279.64    0    0    0
7 1930.01    3491.34    0    0    0
8 1930.01    3445.39    0    0    0
9 1930.01    3494.09    0    0    0
10    1930.01    3460.39    0    0    0
11    1930 3393.99    0    0    0
12    1930 3366.98    0    0    0
13    1930 3517.17    0    0    0
14    1930 3476.71    0    0    0
15    1930 3336.61    0    0    0
16    1930 3394.5 0    0    0
17    1930 3228.42    0    0    0
18    1929.99    3308.06    0    0    0
19    1929.99    3309.47    0    0    0
20    1929.99    3216.21    0    0    0
21    1930.02    3137.19    0    0    0
22    1930.04    2928.1 0    0    0
23    1929.74    2971.97    0    0    0
24    1929.73    3023.44    0    0    0
25    1929.7 3008.77    0    0    0
26    1929.72    3204.24    0    0    0
27    1929.73    3245.07    0    0    0
28    1929.76    3330.96    0    0    0
29    1929.8 3454.8 0    0    0
30    1929.77    3417.01    0    0    0
31    1929.77    3533.83    0    0    0
32    1929.77    3665.63    0    0    0
33    1929.76    3613.11    0    0    0
34    1929.76    3622.36    0    0    0
35    1929.75    3652.2 0    0    0
36    1929.75    3641.09    0    0    0
37    1929.74    3539.73    0    0    0
38    1929.74    3317.55    0    0    0
39    1929.74    3337.88    0    0    0
40    1929.74    3524.06    0    0    0
41    1929.74    3622.4 0    0    0
42    1929.74    3477.03    0    0    0
43    1929.74    3489.14    0    0    0
44    1929.74    3584.08    0    0    0
45    1929.74    3603.49    0    0    0
46    1929.74    3603.93    0    0    0
47    1929.74    3675.45    0    0    0
48    1929.74    3729.32    0    0    0
49    1929.74    3975.98    0    0    0
50    1929.73    3870.46    0    0    0
51    1929.72    3472.22    0    0    0
52    1929.72    3371.76    0    0    0
53    1929.72    3259.59    0    0    0
54    1929.72    3413.24    0    0    0
55    1929.72    3479.56    0    0    0
56    1922.61    3511.71    0    0    0
57    1929.96    3636.23    0    0    0
58    1930.03    3730.75    0    0    0
59    1930.03    3890.47    0    0    0
60    1930.03    3844.97    0    0    0
61    1930.03    3923.12    0    0    0
62    1930.03    3659.91    0    0    0
63    1930.02    3459.26    0    0    0
64    1930.01    3371.03    0    0    0
65    1930.01    3619.22    0    0    0
66    1930.01    3594.27    0    0    0
67    1930.01    3208.31    0    0    0
68    1930 3352.77    0    0    0
69    1930 3399.92    0    0    0
70    1930 3801.24    0    0    0
71    1930 3964.72    0    0    0
72    1930 3998.75    0    0    0
73    1930 3720.92    0    0    0
74    1930 3149.86    0    0    0

PROJECT {
title = 1D-2D Modell
author = Nils
date = 16.11.2022
}
DOMAIN {
PHYSICAL_PROPERTIES {
gravity = 9.81
viscosity = 1e-06
rho_fluid = 1000
}
BASECHAIN_1D {
region_name = Donau
GEOMETRY {
file = Donau.bmg
cross_section_order = (1907500 1907400 1907300 1907200 1907100 1907000 1906900 1906800 1906700 1906600 1906500 1906400 1906300 1906200 1906100 1906000 1905900 1905800 1905700 1905600 1905500 1905400 1905300 1905200 1905100 1905000 1904900 1904800 1904700 1904600 1904500 1904400 1904300 1904200 1904100 1904000 1903900 1903800 1903700 1903600 1903500 1903400 1903300 1903200 1903100 1903000 1902900 1902800 1902700 1902600 1902500 1902400 1902300 1902200 1902100 1902000 1901900 1901800 1901700 1901600 1901500 1901400 1901300 1901200 1901100 1901000 1900900 1900800 1900700 1900600 1900500 1900400 1900300 1900200)
}
HYDRAULICS {
BOUNDARY {
type = hydrograph
string = upstream
file = Hydrograph.txt
slope = 0.46
precision = 0.001
number_of_iterations = 100
}
BOUNDARY {
type = hqrelation
string = downstream
slope = 0.46
}
FRICTION {
type = strickler
default_friction = 35
}
INITIAL {
type = continue
file = Donau_restart_86400.dat
}
PARAMETER {
minimum_water_depth = 0.01
simulation_scheme = explicit
riemann_solver = roe
SECTION_COMPUTATION {
type = table
min_interval = 0.0025
max_interval = 0.2025
}
}
}
TIMESTEP {
total_run_time = 172800
initial_time_step = 1.0
maximum_time_step = 60.0
CFL = 0.95
}
OUTPUT {
output_time_step = 100
console_time_step = 100
}
}
BASEPLANE_2D {
region_name = DonauAuen
GEOMETRY {
type = 2dm
file = DonauAuen.2dm
}
HYDRAULICS {
PARAMETER {
minimum_water_depth = 0.01
}
FRICTION {
type = strickler
wall_friction = off
index = (1 2)
friction = (35 35)
input_type = index_table
default_friction = 35
}
INITIAL {
type = continue
file = DonauAuen_restart.cgns
restart_solution_time = 86400
}
}
TIMESTEP {
total_run_time = 172800
CFL = 0.95
}
OUTPUT {
console_time_step = 100
restart_time_step = 500
SPECIAL_OUTPUT {
type = node_centered
format = sms
values = (velocity depth wse)
output_time_step = 1000
}
SPECIAL_OUTPUT {
type = BASEviz
output_time_step = 1000
}
}
}
COUPLINGS {
PARAMETER {
max_time_level = 1
}
COUPLING_LATERAL {
basechain = Donau
baseplane = DonauAuen
connections_automatic = no
connections_distance = 50.0
connections_index = (1 2)
connections_filename = lateral_connections_created.dat
weir_from_dyke1D = no
damping_factor = 0.5
}
}
PARALLEL {
number_threads = 4
}
}

Last edited by Nils (2022-11-16 17:40:13)

User Forum of Software BASEMENT

#1 2022-11-16 17:38:22

Lateral Coupling 1D-2D: Problem with steady-state simulation

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