texpand shear example, several commands still need to be implemented in `src/` - Granular.jl - Julia package for granular dynamics simulation
(HTM) git clone git://src.adamsgaard.dk/Granular.jl
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---
(DIR) commit 4fb8699a41e180b182edb2063f196e78d777bc75
(DIR) parent 6ea156c479fc26d60eceede529de2a57d7e0ca97
(HTM) Author: Anders Damsgaard <andersd@riseup.net>
Date: Thu, 9 Nov 2017 15:05:34 -0600
expand shear example, several commands still need to be implemented in `src/`
Diffstat:
M examples/shear.jl | 107 +++++++++++++++++++++++++------
1 file changed, 89 insertions(+), 18 deletions(-)
---
(DIR) diff --git a/examples/shear.jl b/examples/shear.jl
t@@ -1,14 +1,22 @@
#/usr/bin/env julia
import Granular
+import JLD
+
+# Common simulation identifier
+const id_prefix = "test0"
################################################################################
#### Step 1: Create a loose granular assemblage and let it settle at -y #
################################################################################
-sim = Granular.createSimulation(id="shear-init")
+sim = Granular.createSimulation(id="$(id_prefix)-init")
# Generate 10 grains along x and 50 grains along y, with radii between 0.2 and
# 1.0 m.
-Granular.regularPacking!(sim, [10, 50], 0.2, 1.0)
+const nx = 10
+const ny = 50
+const r_min = 0.2
+const r_max = 1.0
+Granular.regularPacking!(sim, [nx, ny], r_min, r_max)
# Create a grid for contact searching spanning the extent of the grains
Granular.fitGridToGrains!(sim, sim.ocean)
t@@ -19,7 +27,7 @@ Granular.setGridBoundaryConditions!(sim.ocean, "impermeable", "north south")
Granular.setGridBoundaryConditions!(sim.ocean, "periodic", "east west")
# Add gravitational acceleration to all grains and disable ocean-grid drag
-g = [0., -9.8]
+const g = [0., -9.8]
for grain in sim.grains
Granular.addBodyForce!(grain, grain.mass*g)
Granular.disableOceanDrag!(grain)
t@@ -44,50 +52,113 @@ Granular.run!(sim)
# Try to render the simulation if `pvpython` is installed on the system
Granular.render(sim, trim=false)
+# Save the simulation state to disk in case we need to reuse the current state
+# This step requires the JLD package (Pkg.add("JLD"))
+Granular.writeSimulation(sim)
+
+# Also copy the simulation in memory, in case we want to loop over different
+# normal stresses below:
+sim_init = deepcopy(sim)
################################################################################
#### Step 2: Consolidate the previous output under a constant normal stress #
################################################################################
-# Set all linear and rotational velocities to zero
-Granular.zeroKinematics!(sim)
-
-
-
-
+# Select a normal stress for the consolidation [Pa]
+N = 10e3
+# Rename the simulation so we don't overwrite output from the previous step
+sim.id = "$(id_prefix)-cons-N$(N)Pa"
+# Set all linear and rotational velocities to zero
+Granular.zeroKinematics!(sim)
+# Add a dynamic wall to the top which adds a normal stress downwards. The
+# normal of this wall is downwards, and we place it at the top of the granular
+# assemblage
+y_top = -Inf
+for grain in grains
+ if y_top < grain.lin_pos[2] + grain.contact_radius
+ y_top = grain.lin_pos[2] + grain.contact_radius
+ end
+end
+Granular.addDynamicWall!(sim, normal=[0., -1.], pos=y_top,
+ boundary_condition="normal stress",
+ normal_stress=N)
+# Resize the grid to span the current state
+Granular.fitGridToGrains!(sim, sim.ocean)
+# Lock the grains at the very bottom so that the lower boundary is rough
+y_bot = Inf
+for grain in grains
+ if y_bot > grain.lin_pos[2] - grain.contact_radius
+ y_bot = grain.lin_pos[2] - grain.contact_radius
+ end
+end
+const fixed_thickness = 2. * r_max
+for grain in grains
+ if grain.lin_pos[2] <= fixed_thickness
+ grain.fixed = true
+ end
+end
+# Set current time to zero and reset output file counter
+Granular.resetTime!(sim)
+# Set the simulation time to run the consolidation for
+Granular.setTotalTime!(sim, 5.0)
+# Run the consolidation experiment
+Granular.run!(sim)
+# Save the simulation state to disk in case we need to reuse the consolidated
+# state (e.g. different shear velocities below)
+Granular.writeSimulation(sim)
+# Also copy the simulation in memory, in case we want to loop over different
+# normal stresses below:
+sim_cons = deepcopy(sim)
################################################################################
#### Step 3: Shear the consolidated assemblage with a constant velocity #
################################################################################
+# Select a shear velocity for the consolidation [m/s]
+const v_shear = 0.1
+# Rename the simulation so we don't overwrite output from the previous step
+sim.id = "$(id_prefix)-shear-N$(N)Pa-v_shear$(v_shear)m-s"
+# Set all linear and rotational velocities to zero
+Granular.zeroKinematics!(sim)
+# Prescribe the shear velocity to the uppermost grains
+for grain in grains
+ if grain.lin_pos[2] <= fixed_thickness
+ # do not allow changes in velocity
+ grain.fixed = true
+
+ # allow free up/down movement to permit dilation, which partially
+ # overrides the `fixed` flag
+ grain.allow_y_acc = true
+ grain.lin_vel[1] = v_shear
+ end
+end
+# Set current time to zero and reset output file counter
+Granular.resetTime!(sim)
+# Set the simulation time to run the shear experiment for
+Granular.setTotalTime!(sim, 15.0)
+# Run the consolidation experiment
+Granular.run!(sim)
-
-
-
-
-
-
-
-
-
+# Save the simulation state to disk in case we need to reuse the sheared state
+Granular.writeSimulation(sim)