Adding a new SPH solver that is more physically accurate. See patch #29681

    http://projects.blender.org/tracker/index.php?func=detail&aid=29681&group_id=9&atid=127

The solver was mostly implemented by John Mansour at VPAC, with help from me and with funding from the AutoCRC. The SPH formulation is due to Gingold and Monaghan, and the smoothing kernel is due to Wendland.

This solver does not replace the old one; it is available as an option. Note that the new solver uses different units than the old one. The patch page has a couple of attachments that can be used to test the new solver, particularly sphclassical_dam_s0.01_grav.blend (ignore the earlier tests). The simulation in that file compares well with a physical experimental dam break; details in a paper by Changhong Hu and Makoto Sueyoshi, also referred to on that page.

1 files changed, 42 insertions, 27 deletions

diff --git a/release/scripts/startup/bl_ui/properties_particle.py b/release/scripts/startup/bl_ui/properties_particle.py
index 75154550bcb..2c2ced5db0c 100644
--- a/release/scripts/startup/bl_ui/properties_particle.py
+++ b/release/scripts/startup/bl_ui/properties_particle.py
@@ -506,6 +506,10 @@ class PARTICLE_PT_physics(ParticleButtonsPanel, Panel):
                 fluid = part.fluid
 
                 split = layout.split()
+                sub = split.row()
+                sub.prop(fluid, "solver", expand=True)
+
+                split = layout.split()
 
                 col = split.column()
                 col.label(text="Fluid properties:")
@@ -516,13 +520,14 @@ class PARTICLE_PT_physics(ParticleButtonsPanel, Panel):
                 col = split.column()
                 col.label(text="Advanced:")
 
-                sub = col.row()
-                sub.prop(fluid, "repulsion", slider=fluid.factor_repulsion)
-                sub.prop(fluid, "factor_repulsion", text="")
+                if fluid.solver == 'DDR':
+                    sub = col.row()
+                    sub.prop(fluid, "repulsion", slider=fluid.factor_repulsion)
+                    sub.prop(fluid, "factor_repulsion", text="")
 
-                sub = col.row()
-                sub.prop(fluid, "stiff_viscosity", slider=fluid.factor_stiff_viscosity)
-                sub.prop(fluid, "factor_stiff_viscosity", text="")
+                    sub = col.row()
+                    sub.prop(fluid, "stiff_viscosity", slider=fluid.factor_stiff_viscosity)
+                    sub.prop(fluid, "factor_stiff_viscosity", text="")
 
                 sub = col.row()
                 sub.prop(fluid, "fluid_radius", slider=fluid.factor_radius)
@@ -532,27 +537,37 @@ class PARTICLE_PT_physics(ParticleButtonsPanel, Panel):
                 sub.prop(fluid, "rest_density", slider=fluid.factor_density)
                 sub.prop(fluid, "factor_density", text="")
 
-                split = layout.split()
-
-                col = split.column()
-                col.label(text="Springs:")
-                col.prop(fluid, "spring_force", text="Force")
-                col.prop(fluid, "use_viscoelastic_springs")
-                sub = col.column(align=True)
-                sub.active = fluid.use_viscoelastic_springs
-                sub.prop(fluid, "yield_ratio", slider=True)
-                sub.prop(fluid, "plasticity", slider=True)
-
-                col = split.column()
-                col.label(text="Advanced:")
-                sub = col.row()
-                sub.prop(fluid, "rest_length", slider=fluid.factor_rest_length)
-                sub.prop(fluid, "factor_rest_length", text="")
-                col.label(text="")
-                sub = col.column()
-                sub.active = fluid.use_viscoelastic_springs
-                sub.prop(fluid, "use_initial_rest_length")
-                sub.prop(fluid, "spring_frames", text="Frames")
+                if fluid.solver == 'CLASSICAL':
+                    # With the classical solver, it is possible to calculate the
+                    # spacing between particles when the fluid is at rest. This
+                    # makes it easier to set stable initial conditions.
+                    particle_volume = part.mass / fluid.rest_density
+                    spacing = pow(particle_volume, 1/3)
+                    sub = col.row()
+                    sub.label(text="Spacing: %g" % spacing)
+
+                elif fluid.solver == 'DDR':
+                    split = layout.split()
+
+                    col = split.column()
+                    col.label(text="Springs:")
+                    col.prop(fluid, "spring_force", text="Force")
+                    col.prop(fluid, "use_viscoelastic_springs")
+                    sub = col.column(align=True)
+                    sub.active = fluid.use_viscoelastic_springs
+                    sub.prop(fluid, "yield_ratio", slider=True)
+                    sub.prop(fluid, "plasticity", slider=True)
+
+                    col = split.column()
+                    col.label(text="Advanced:")
+                    sub = col.row()
+                    sub.prop(fluid, "rest_length", slider=fluid.factor_rest_length)
+                    sub.prop(fluid, "factor_rest_length", text="")
+                    col.label(text="")
+                    sub = col.column()
+                    sub.active = fluid.use_viscoelastic_springs
+                    sub.prop(fluid, "use_initial_rest_length")
+                    sub.prop(fluid, "spring_frames", text="Frames")
 
         elif part.physics_type == 'KEYED':
             split = layout.split()