tbreakup.jl - seaice-experiments - sea ice experiments using Granular.jl
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---
tbreakup.jl (15190B)
---
1 #!/usr/bin/env julia
2 import Granular
3 import ArgParse
4 import Plots
5
6 verbose = false
7
8 function parse_command_line()
9 s = ArgParse.ArgParseSettings()
10 ArgParse.@add_arg_table s begin
11 "--width"
12 help = "strait width [m]"
13 arg_type = Float64
14 default = 5e3
15 "--E"
16 help = "Young's modulus [Pa]"
17 arg_type = Float64
18 default = 0.
19 "--nu"
20 help = "Poisson's ratio [-]"
21 arg_type = Float64
22 default = 0.
23 "--k_n"
24 help = "normal stiffness [N/m]"
25 arg_type = Float64
26 default = 1e7
27 "--k_t"
28 help = "tangential stiffness [N/m]"
29 arg_type = Float64
30 default = 1e7
31 "--gamma_n"
32 help = "normal viscosity [N/(m/s)]"
33 arg_type = Float64
34 default = 0.
35 "--gamma_t"
36 help = "tangential viscosity [N/(m/s)]"
37 arg_type = Float64
38 default = 0.
39 "--mu_s"
40 help = "static friction coefficient [-]"
41 arg_type = Float64
42 default = 0.5
43 "--mu_d"
44 help = "dynamic friction coefficient [-]"
45 arg_type = Float64
46 default = 0.5
47 "--tensile_strength"
48 help = "the maximum tensile strength [Pa]"
49 arg_type = Float64
50 default = 0.
51 "--r"
52 help = "grain radius [m]"
53 arg_type = Float64
54 default = 1e3
55 "--rotating"
56 help = "allow the grains to rotate"
57 arg_type = Bool
58 default = true
59 "--ocean_vel_fac"
60 help = "ocean velocity factor [-]"
61 arg_type = Float64
62 default = 2e4
63 "--total_hours"
64 help = "hours of simulation time [h]"
65 arg_type = Float64
66 default = 6.
67 "--nruns"
68 help = "number of runs in ensemble"
69 arg_type = Int
70 default = 1
71 "id"
72 help = "simulation id"
73 required = true
74 end
75 return ArgParse.parse_args(s)
76 end
77
78 function report_args(parsed_args)
79 println("Parsed args:")
80 for (arg,val) in parsed_args
81 println(" $arg => $val")
82 end
83 end
84
85 function run_simulation(id::String,
86 width::Float64,
87 E::Float64,
88 nu::Float64,
89 k_n::Float64,
90 k_t::Float64,
91 gamma_n::Float64,
92 gamma_t::Float64,
93 mu_s::Float64,
94 mu_d::Float64,
95 tensile_strength::Float64,
96 r::Float64,
97 rotating::Bool,
98 ocean_vel_fac::Float64,
99 total_hours::Float64,
100 seed::Int)
101
102 info("## EXPERIMENT: " * id * " ##")
103 sim = Granular.createSimulation(id=id)
104
105 Lx = 50.e3
106 Lx_constriction = width
107 L = [Lx, Lx*1.5, 1e3]
108 Ly_constriction = 20e3
109 dx = r*2.
110
111 n = [Int(ceil(L[1]/dx/2.)), Int(ceil(L[2]/dx/2.)), 2]
112
113 # Initialize confining walls, which are grains that are fixed in space
114 h = 1.
115 r_walls = r/2.
116
117 ## N-S segments
118 for y in linspace((L[2] - Ly_constriction)/2.,
119 Ly_constriction + (L[2] - Ly_constriction)/2.,
120 Int(round(Ly_constriction/(r_walls*2))))
121 Granular.addGrainCylindrical!(sim, [(Lx - Lx_constriction)/2., y],
122 r_walls, h, fixed=true, verbose=false)
123 end
124 for y in linspace((L[2] - Ly_constriction)/2.,
125 Ly_constriction + (L[2] - Ly_constriction)/2.,
126 Int(round(Ly_constriction/(r_walls*2))))
127 Granular.addGrainCylindrical!(sim, [Lx_constriction + (L[1] -
128 Lx_constriction)/2., y], r_walls, h,
129 fixed=true, verbose=false)
130 end
131
132 dx = 2.*r_walls*sin(atan((Lx - Lx_constriction)/(L[2] - Ly_constriction)))
133
134 ## NW diagonal
135 x = r_walls:dx:((Lx - Lx_constriction)/2.)
136 y = linspace(L[2] - r_walls, (L[2] - Ly_constriction)/2. + Ly_constriction +
137 r_walls, length(x))
138 for i in 1:length(x)
139 Granular.addGrainCylindrical!(sim, [x[i], y[i]], r_walls, h, fixed=true,
140 verbose=false)
141 end
142
143 ## NE diagonal
144 x = (L[1] - r_walls):(-dx):((Lx - Lx_constriction)/2. + Lx_constriction)
145 y = linspace(L[2] - r_walls, (L[2] - Ly_constriction)/2. + Ly_constriction +
146 r_walls, length(x))
147 for i in 1:length(x)
148 Granular.addGrainCylindrical!(sim, [x[i], y[i]], r_walls, h, fixed=true,
149 verbose=false)
150 end
151
152 ## SW diagonal
153 x = r_walls:dx:((Lx - Lx_constriction)/2.)
154 y = linspace(r, (L[2] - Ly_constriction)/2. - r_walls, length(x))
155 for i in 1:length(x)
156 Granular.addGrainCylindrical!(sim, [x[i], y[i]], r_walls, h, fixed=true,
157 verbose=false)
158 end
159
160 ## SE diagonal
161 x = (L[1] - r_walls):(-dx):((Lx - Lx_constriction)/2. + Lx_constriction)
162 y = linspace(r_walls, (L[2] - Ly_constriction)/2. - r_walls, length(x))
163 for i in 1:length(x)
164 Granular.addGrainCylindrical!(sim, [x[i], y[i]], r_walls, h, fixed=true,
165 verbose=false)
166 end
167
168 n_walls = length(sim.grains)
169 info("added $(n_walls) fixed grains as walls")
170
171 # Initialize ocean
172 sim.ocean = Granular.createRegularOceanGrid(n, L, name="poiseuille_flow")
173
174 # Determine stream function value for all grid cells, row by row.
175 # At y=0 and y=Ly: psi = a*ocean_vel_fac*(x - Lx/2.).^3 with a = 1.
176 # The value of a increases when strait is narrow, and psi values are
177 # constant outside domain>
178 psi = similar(sim.ocean.v[:, :, 1, 1])
179 Granular.sortGrainsInGrid!(sim, sim.ocean)
180 for j=1:size(psi, 2)
181
182 # Check width of domain in the current row
183 if sim.ocean.yq[1, j] < (L[2] - Ly_constriction)/2.
184 # lower triangle
185 W = (Lx - width)*
186 (1. - sim.ocean.yq[1, j]/((L[2] - Ly_constriction)/2.)) + width
187
188 elseif sim.ocean.yq[1, j] < Ly_constriction+(L[2] - Ly_constriction)/2.
189 # strait
190 W = width
191
192 else
193 y_min = Ly_constriction + (L[2] - Ly_constriction)/2.
194
195 # upper triangle
196 W = (Lx - width)*(sim.ocean.yq[1, j] - y_min)/(L[2] - y_min) + width
197 end
198
199 # transform [Lx/2 - W/2; Lx/2 + W/2] to [-2;2]
200 x_ = (sim.ocean.xq[:, j] - (Lx/2. - W/2.))/W*4. - 2.
201
202 psi[:, j] = tanh(x_)
203 end
204
205 # determine ocean velocities (u and v) from stream function derivatives
206 for i=1:size(psi, 1)
207 if i == 1
208 sim.ocean.v[i, :, 1, 1] = -(psi[i+1, :] - psi[i, :])./
209 (sim.ocean.xq[i+1, :] - sim.ocean.xq[i, :])
210 elseif i == size(psi, 1)
211 sim.ocean.v[i, :, 1, 1] = -(psi[i, :] - psi[i-1, :])./
212 (sim.ocean.xq[i, :] - sim.ocean.xq[i-1, :])
213 else
214 sim.ocean.v[i, :, 1, 1] = -(psi[i+1, :] - psi[i-1, :])./
215 (sim.ocean.xq[i+1, :] - sim.ocean.xq[i-1, :])
216 end
217 end
218
219 for j=1:size(psi, 2)
220 if j == 1
221 sim.ocean.u[:, j, 1, 1] = (psi[:, j+1] - psi[:, j])./
222 (sim.ocean.yq[:, j+1] - sim.ocean.yq[:, j])
223 elseif j == size(psi, 2)
224 sim.ocean.u[:, j, 1, 1] = (psi[:, j] - psi[:, j-1])./
225 (sim.ocean.yq[:, j] - sim.ocean.yq[:, j-1])
226 else
227 sim.ocean.u[:, j, 1, 1] = (psi[:, j+1] - psi[:, j-1])./
228 (sim.ocean.yq[:, j+1] - sim.ocean.yq[:, j-1])
229 end
230 end
231 sim.ocean.h[:,:,1,1] = psi # this field is unused; use for stream function
232 sim.ocean.u *= ocean_vel_fac
233 sim.ocean.v *= ocean_vel_fac
234
235 # Constant velocities along y:
236 #sim.ocean.v[:, :, 1, 1] = ocean_vel_fac*((sim.ocean.xq - Lx/2.).^2 -
237 # Lx^2./4.)
238
239
240 # Initialize grains in wedge north of the constriction
241 iy = 1
242 dy = sqrt((2.*r_walls)^2. - dx^2.)
243 spacing_to_boundaries = 2.*r
244 #floe_padding = .5*r
245 floe_padding = 0.
246 noise_amplitude = floe_padding
247 Base.Random.srand(seed)
248 y_spacing = 2.*r*cos(pi/6.) + floe_padding
249 for y in (L[2] - r - noise_amplitude):(-y_spacing):((L[2] -
250 Ly_constriction)/2. + Ly_constriction)
251 for x in (r + noise_amplitude):(2.*r + floe_padding):(Lx - r -
252 noise_amplitude)
253 if iy % 2 == 0
254 x += r
255 end
256
257 x_ = x + noise_amplitude*(0.5 - Base.Random.rand())
258 y_ = y + noise_amplitude*(0.5 - Base.Random.rand())
259
260 if y_ < -dy/dx*x_ + L[2] + spacing_to_boundaries
261 continue
262 end
263
264 if y_ < dy/dx*x_ + (L[2] - dy/dx*Lx) + spacing_to_boundaries
265 continue
266 end
267
268 Granular.addGrainCylindrical!(sim, [x_, y_], r, h, verbose=false)
269 end
270 iy += 1
271 end
272 n = length(sim.grains) - n_walls
273 info("added $(n) grains")
274
275 # Remove old simulation files
276 Granular.removeSimulationFiles(sim)
277
278 for i=1:length(sim.grains)
279 sim.grains[i].youngs_modulus = E
280 sim.grains[i].poissons_ratio = nu
281 sim.grains[i].contact_stiffness_normal = k_n
282 sim.grains[i].contact_stiffness_tangential = k_t
283 sim.grains[i].contact_viscosity_normal = gamma_n
284 sim.grains[i].contact_viscosity_tangential = gamma_t
285 sim.grains[i].contact_static_friction = mu_s
286 sim.grains[i].contact_dynamic_friction = mu_d
287 sim.grains[i].tensile_strength = tensile_strength
288 sim.grains[i].rotating = rotating
289 end
290
291 # Set temporal parameters
292 Granular.setTotalTime!(sim, total_hours*60.*60.)
293 Granular.setOutputFileInterval!(sim, 60.*5.) # output every 5 mins
294 Granular.setTimeStep!(sim, verbose=verbose)
295 Granular.writeVTK(sim, verbose=verbose)
296
297 profile = false
298
299 ice_flux = Float64[]
300 jammed = false
301 it_before_eval = 10
302 time_jammed = 0.
303 time_jammed_criterion = 60.*60. # define as jammed after this duration
304
305 while sim.time < sim.time_total
306
307 # run simulation for it_before_eval time steps
308 for it=1:it_before_eval
309 if sim.time >= sim.time_total*.75 && profile
310 @profile Granular.run!(sim, status_interval=1, single_step=true,
311 verbose=verbose, show_file_output=verbose)
312 Profile.print()
313 profile = false
314 else
315 Granular.run!(sim, status_interval=1, single_step=true,
316 verbose=verbose, show_file_output=verbose)
317 end
318 end
319
320 # assert if the system is jammed by looking at ice-floe mass change in
321 # the number of jammed grains
322 if jammed
323 time_jammed += sim.time_dt*float(it_before_eval)
324 if time_jammed >= 60.*60. # 1 h
325 info("$t s: system jammed for more than " *
326 "$time_jammed_criterion s, stopping simulation")
327 exit()
328 end
329 end
330
331 ice_mass_outside_domain = 0.
332 for icefloe in sim.grains
333 if !icefloe.enabled
334 ice_mass_outside_domain += icefloe.mass
335 end
336 end
337 append!(ice_flux, ice_mass_outside_domain)
338
339 # add new grains from the top
340 for i=1:size(sim.ocean.xh, 1)
341 if sim.ocean.grain_list[i, end] == []
342
343 x, y = Granular.getCellCenterCoordinates(sim.ocean, i,
344 size(sim.ocean.xh, 2))
345
346 x_ = x + noise_amplitude*(0.5 - Base.Random.rand())
347 y_ = y + noise_amplitude*(0.5 - Base.Random.rand())
348
349 Granular.addGrainCylindrical!(sim, [x_, y_], r, h, verbose=false,
350 youngs_modulus=E,
351 poissons_ratio=nu,
352 contact_stiffness_normal=k_n,
353 contact_stiffness_tangential=k_t,
354 contact_viscosity_normal=gamma_n,
355 contact_viscosity_tangential=gamma_t,
356 contact_static_friction = mu_s,
357 contact_dynamic_friction = mu_d,
358 tensile_strength = tensile_strength,
359 rotating=rotating)
360 end
361 end
362 end
363
364 t = linspace(0., sim.time_total, length(ice_flux))
365 writedlm(sim.id * "-ice-flux.txt", [t, ice_flux])
366 return t, ice_flux
367 end
368
369 function main()
370 parsed_args = parse_command_line()
371 report_args(parsed_args)
372
373 nruns = parsed_args["nruns"]
374 t = Float64[]
375 t_jam = ones(nruns)*parsed_args["total_hours"]*60.*60.*2.
376 Plots.gr()
377
378 for i=1:nruns
379 seed = i
380 t, ice_flux = run_simulation(parsed_args["id"] * "-seed" * string(seed),
381 parsed_args["width"],
382 parsed_args["E"],
383 parsed_args["nu"],
384 parsed_args["k_n"],
385 parsed_args["k_t"],
386 parsed_args["gamma_n"],
387 parsed_args["gamma_t"],
388 parsed_args["mu_s"],
389 parsed_args["mu_d"],
390 parsed_args["tensile_strength"],
391 parsed_args["r"],
392 parsed_args["rotating"],
393 parsed_args["ocean_vel_fac"],
394 parsed_args["total_hours"],
395 i)
396 Plots.plot!(t/(60.*60.), ice_flux)
397
398 time_elapsed_while_jammed = 0.
399 for it=(length(t) - 1):-1:1
400 if ice_flux[it] ≈ ice_flux[end]
401 time_elapsed_while_jammed = t[end] - t[it]
402 end
403 end
404
405 if time_elapsed_while_jammed > 60.*60.
406 t_jam[i] = t[end] - time_elapsed_while_jammed
407 info("simulation $i jammed at t = $(t_jam[i]/(60.*60.)) h")
408 end
409
410 end
411 Plots.title!(parsed_args["id"])
412 Plots.xaxis!("Time [h]")
413 Plots.yaxis!("Cumulative ice throughput [kg]")
414
415 Plots.savefig(parsed_args["id"])
416 Plots.closeall()
417
418 jam_fraction = zeros(length(t))
419 for it=1:length(t)
420 for i=1:nruns
421 if t_jam[i] <= t[it]
422 jam_fraction[it] += 1./float(nruns)
423 end
424 end
425 end
426 Plots.plot(t/(60.*60.), jam_fraction)
427 Plots.title!(parsed_args["id"] * ", N = " * string(nruns))
428 Plots.xaxis!("Time [h]")
429 Plots.yaxis!("Fraction of runs jammed [-]")
430 Plots.savefig(parsed_args["id"] * "-jam_fraction.pdf")
431 end
432
433 main()