source: anuga_work/development/shallow_water_1d/config.py @ 4960

Last change on this file since 4960 was 4946, checked in by sudi, 16 years ago

Upload 1D version of ANUGA created by John Jakeman and currently being investigated by Sudi Mungaski

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1"""Module where global model parameters are set
2"""
3
4epsilon = 1.0e-12
5
6default_boundary_tag = 'exterior'
7
8
9time_format = '%d/%m/%y %H:%M:%S'
10
11min_timestep = 1.0e-6 #Should be computed based on geometry
12max_timestep = 1000
13#This is how:
14#Define maximal possible speed in open water v_max, e.g. 500m/s (soundspeed?)
15#Then work out minimal internal distance in mesh r_min and set
16#min_timestep = r_min/v_max
17#
18#Max speeds are calculated in the flux function as
19#
20#lambda = v +/- sqrt(gh)
21#
22# so with 500 m/s, h ~ 500^2/g = 2500 m well out of the domain of the
23# shallow water wave equation
24#
25#The actual soundspeed can be as high as 1530m/s
26#(see http://staff.washington.edu/aganse/public.projects/clustering/clustering.html),
27#but that would only happen with h>225000m in this equation. Why ?
28#The maximal speed we specify is really related to the max speed
29#of surface pertubation
30#
31
32
33v_max = 100 #For use in domain_ext.c
34sound_speed = 500
35
36
37max_smallsteps = 50  #Max number of degenerate steps allowed b4 trying first order
38
39manning = 0.3  #Manning's friction coefficient
40g = 9.8       #Gravity
41#g(phi) = 9780313 * (1 + 0.0053024 sin(phi)**2 - 0.000 0059 sin(2*phi)**2) micro m/s**2, where phi is the latitude
42#The 'official' average is 9.80665
43
44
45
46
47eta_w = 3.0e-3 #Wind stress coefficient
48rho_a = 1.2e-3 #Atmospheric density
49rho_w = 1023   #Fluid density [kg/m^3] (rho_w = 1023 for salt water)
50
51
52#Betas [0;1] control the allowed steepness of gradient for second order
53#extrapolations. Values of 1 allow the steepes gradients while
54#lower values are more conservative. Values of 0 correspond to
55#1'st order extrapolations.
56#
57# Large values of beta_h may cause simulations to require more timesteps
58# as surface will 'hug' closer to the bed.
59# Small values of beta_h will make code faster, but one may experience
60# artificial momenta caused by discontinuities in water depths in
61# the presence of steep slopes. One example of this would be
62# stationary water 'lapping' upwards to a higher point on the coast.
63#
64#
65#
66#There are separate betas for the w-limiter and the h-limiter
67#
68#
69#
70#
71#Good values are:
72#beta_w = 0.9
73#beta_h = 0.2
74
75
76
77beta_w = 0.9
78beta_h = 0.2
79CFL = 1.0  #FIXME (ole): Is this in use yet??
80           #(Steve) yes, change domain.CFL to
81           #make changes
82
83
84pmesh_filename = '.\\pmesh'
85
86
87import os, sys
88
89if sys.platform == 'win32':
90    #default_datadir = 'C:\grohm_output'
91    default_datadir = '.'
92else:
93    #default_datadir = os.path.expanduser('~'+os.sep+'grohm_output')
94    default_datadir = '.'
95
96
97use_extensions = True    #Try to use C-extensions
98#use_extensions = False   #Do not use C-extensions
99
100use_psyco = True  #Use psyco optimisations
101#use_psyco = False  #Do not use psyco optimisations
102
103
104optimised_gradient_limiter = True #Use hardwired gradient limiter
105
106#Specific to shallow water W.E.
107minimum_allowed_height = 1.0e-3 #Water depth below which it is considered to be 0
108maximum_allowed_speed = 100.0
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