texperiment with different parameter values for erosion/deposition - granular-channel-hydro - subglacial hydrology model for sedimentary channels
(HTM) git clone git://src.adamsgaard.dk/granular-channel-hydro
(DIR) Log
(DIR) Files
(DIR) Refs
(DIR) README
(DIR) LICENSE
---
(DIR) commit 464ba42ad1e569c9c86c0b29e272ad9555b32feb
(DIR) parent 400da52ca6dea9a381f902ba653ca1c267ac286f
(HTM) Author: Anders Damsgaard Christensen <adc@geo.au.dk>
Date: Thu, 2 Feb 2017 16:46:46 -0800
experiment with different parameter values for erosion/deposition
Diffstat:
M 1d-channel.py | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)
---
(DIR) diff --git a/1d-channel.py b/1d-channel.py
t@@ -23,7 +23,7 @@ import sys
# # Model parameters
Ns = 25 # Number of nodes [-]
Ls = 100e3 # Model length [m]
-t_end = 24.*60.*60.*2 # Total simulation time [s]
+t_end = 24.*60.*60.*365 # Total simulation time [s]
tol_Q = 1e-3 # Tolerance criteria for the normalized max. residual for Q
tol_P_c = 1e-3 # Tolerance criteria for the normalized max residual for P_c
max_iter = 1e2*Ns # Maximum number of solver iterations before failure
t@@ -44,8 +44,9 @@ m_dot = 4.5e-7
# Walder and Fowler 1994 sediment transport parameters
K_e = 0.1 # Erosion constant [-], disabled when 0.0
-K_d = 6.0 # Deposition constant [-], disabled when 0.0
-alpha = 2e5 # Geometric correction factor (Carter et al 2017)
+# K_d = 6.0 # Deposition constant [-], disabled when 0.0
+K_d = 0.1 # Deposition constant [-], disabled when 0.0
+alpha = 1e5 # Geometric correction factor (Carter et al 2017)
# D50 = 1e-3 # Median grain size [m]
# tau_c = 0.5*g*(rho_s - rho_i)*D50 # Critical shear stress for transport
d15 = 1e-3 # Characteristic grain size [m]
t@@ -85,7 +86,7 @@ hydro_pot = rho_w*g*b + p_w # Initial guess of hydraulic potential [Pa]
# Initialize arrays for channel segments between nodes
S = numpy.ones(len(s) - 1)*S_min # Cross-sect. area of channel segments[m^2]
S_max = numpy.zeros_like(S) # Max. channel size [m^2]
-dSdt = numpy.empty_like(S) # Transient in channel cross-sect. area [m^2/s]
+dSdt = numpy.zeros_like(S) # Transient in channel cross-sect. area [m^2/s]
W = S/numpy.tan(numpy.deg2rad(theta)) # Assuming no channel floor wedge
Q = numpy.zeros_like(S) # Water flux in channel segments [m^3/s]
Q_s = numpy.zeros_like(S) # Sediment flux in channel segments [m^3/s]
t@@ -124,9 +125,10 @@ def channel_shear_stress(Q, S):
def channel_erosion_rate(tau):
# Parker 1979, Walder and Fowler 1994
- # return K_e*v_s*(tau - tau_c).clip(min=0.)/(g*(rho_s - rho_w)*d15)
+ # return K_e*v_s*(tau - tau_c).clip(min=0.)/(g*(rho_s - rho_w)*d15)**(3./2)
# Carter et al 2017
- return K_e*v_s/alpha*(tau - tau_c).clip(min=0.)/(g*(rho_s - rho_w)*d15)
+ return K_e*v_s/alpha*(tau - tau_c).clip(min=0.) / \
+ (g*(rho_s - rho_w)*d15)**(3./2.)
def channel_deposition_rate_kernel(tau, c_bar, ix):
t@@ -200,6 +202,7 @@ def update_channel_size_with_limit(S, dSdt, dt, N):
# Damsgaard et al, in prep
S_max = ((c_1*N.clip(min=0.)/1000. + c_2) *
numpy.tan(numpy.deg2rad(theta))).clip(min=S_min)
+ S_max[:] = 1000.
S = numpy.minimum(S + dSdt*dt, S_max).clip(min=S_min)
W = S/numpy.tan(numpy.deg2rad(theta)) # Assume no channel floor wedge
return S, W, S_max
t@@ -391,11 +394,11 @@ while time <= t_end:
# Find new effective pressure in channel segments
N_c = rho_i*g*H_c - P_c
- plot_state(step, time)
+ if step % 10 == 0:
+ plot_state(step, time)
# import ipdb; ipdb.set_trace()
- #if step > 0:
- #break
+ # if step > 0: break
# Update time
time += dt