tadd cell-based contact search - Granular.jl - Julia package for granular dynamics simulation
(HTM) git clone git://src.adamsgaard.dk/Granular.jl
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---
(DIR) commit eeb31284d08583ecaa038ef8fb55d77692c48e71
(DIR) parent a79f1155bfb16f8da74ac94efe92e7d9eff79fb3
(HTM) Author: Anders Damsgaard <andersd@riseup.net>
Date: Sun, 30 Apr 2017 14:25:22 -0400
add cell-based contact search
Diffstat:
M src/contact_search.jl | 47 +++++++++++++++++++++++++++++++
M src/ocean.jl | 6 +++---
2 files changed, 50 insertions(+), 3 deletions(-)
---
(DIR) diff --git a/src/contact_search.jl b/src/contact_search.jl
t@@ -47,6 +47,8 @@ end
export findContactsAllToAll!
"""
+ findContactsAllToAll!(simulation)
+
Perform an O(n^2) all-to-all contact search between all ice floes in the
`simulation` object. Contacts between fixed ice floes are ignored.
"""
t@@ -77,3 +79,48 @@ function findContactsAllToAll!(simulation::Simulation)
end
end
end
+
+export findContactsOceanGrid!
+"""
+ findContactsOceanGrid!(simulation)
+
+Perform an O(n*log(n)) cell-based contact search between all ice floes in the
+`simulation` object. Contacts between fixed ice floes are ignored.
+"""
+function findContactsOceanGrid!(simulation::Simulation)
+
+ for idx_i = 1:length(simulation.ice_floes)
+
+ grid_pos = simulation.ice_floes[idx_i].ocean_grid_pos
+ nx, ny = size(simulation.ocean.xh)
+
+ for i=(grid_pos[1] - 1):(grid_pos[1] + 1)
+ for j=(grid_pos[2] - 1):(grid_pos[2] + 1)
+
+ # only check for contacts within grid boundaries
+ if i < 1 || i > nx || j < 1 || j > ny
+ continue
+ end
+
+ for idx_j in simulation.ocean.ice_floe_list[i, j]
+
+ if idx_i < idx_j
+
+ # Inter-grain position vector and grain overlap
+ position_ij = interIceFloePositionVector(simulation,
+ idx_i, idx_j)
+ overlap_ij = findOverlap(simulation, idx_i, idx_j,
+ position_ij)
+
+ # Check if grains overlap (overlap when negative)
+ if overlap_ij < 0.0
+ push!(simulation.contact_pairs, [idx_i, idx_j])
+ push!(simulation.overlaps,
+ overlap_ij*position_ij/norm(position_ij))
+ end
+ end
+ end
+ end
+ end
+ end
+end
(DIR) diff --git a/src/ocean.jl b/src/ocean.jl
t@@ -279,12 +279,12 @@ function applyOceanDragToIceFloe!(ice_floe::IceFloeCylindrical,
freeboard = .1*ice_floe.thickness # height above water
rho_o = 1000. # ocean density
draft = ice_floe.thickness - freeboard # height of submerged thickness
- c_o_v = 123 # ocean drag coefficient, vertical
- c_o_h = 123 # ocean drag coefficient, horizontal
+ c_o_v = .85 # ocean drag coefficient, vertical, Hunke and Comeau 2011
+ c_o_h = 5e-4 # ocean drag coefficient, horizontal
length = ice_floe.areal_radius*2.
width = ice_floe.areal_radius*2.
ice_floe.force +=
rho_o * (.5*c_o_v*width*draft*freeboard + c_o_h*length*width) *
- ([u, v] - ice_floe.vel)*norm([u, v] - ice_floe.vel)
+ ([u, v] - ice_floe.lin_vel)*norm([u, v] - ice_floe.lin_vel)
end