Merged in arpitragarwal/pysph/TVF_no_slip (pull request #138)

BUG: Correcting the velocity extrapolation for the no-slip BC

examples/SPHERIC/moving_square.py

@@ -22,8 +22,8 @@
 from pysph.sph.wc.transport_velocity import SummationDensity,\
     StateEquation, MomentumEquationPressureGradient, MomentumEquationViscosity,\
     MomentumEquationArtificialStress, SolidWallPressureBC, SolidWallNoSlipBC,\
-    ShepardFilteredVelocity
-		
+    SetWallVelocity
+
 # domain and reference values
 Lx = 10.0; Ly = 5.0
 Umax = 1.0
@@ -83,9 +83,16 @@ def _setup_particle_properties(particles, volume):
     solid.add_property('V' )
     obstacle.add_property('V' )
 
-    # Shepard filtered velocities for the fluid
+    # extrapolated velocities for the fluid
     for name in ['uf', 'vf', 'wf']:
-        fluid.add_property(name)
+        solid.add_property(name)
+        obstacle.add_property(name)
+
+    # dummy velocities for the solid and obstacle
+    # required for the no-slip BC
+    for name in ['ug', 'vg', 'wg']:
+        solid.add_property(name)
+        obstacle.add_property(name)
 
     # advection velocities and accelerations for fluid
     for name in ('uhat', 'vhat', 'what', 'auhat', 'avhat', 'awhat', 'au', 'av', 'aw'):
@@ -238,7 +245,7 @@ def loop(self, d_idx, d_ax, t=0.0):
 equations = [
 
     # set the acceleration for the obstacle using the special function
-    # mimicing the accelerations provided in the test.
+    # mimicking the accelerations provided in the test.
     Group(
         equations=[
             SPHERICBenchmarkAcceleration(dest='obstacle', sources=None),
@@ -254,14 +261,14 @@ def loop(self, d_idx, d_ax, t=0.0):
             SummationDensity(dest='fluid', sources=['fluid','solid','obstacle']),
             ], real=False),
 
-
     # Once the fluid density is computed, we can use the EOS to set
-    # the fluid pressure. Additionally, the shepard filtered velocity
-    # for the fluid phase is determined.
+    # the fluid pressure. Additionally, the dummy velocity for the
+    # channel is set, which is later used in the no-slip wall BC.
     Group(
         equations=[
             StateEquation(dest='fluid', sources=None, p0=p0, rho0=rho0, b=1.0),
-            ShepardFilteredVelocity(dest='fluid', sources=['fluid']),
+            SetWallVelocity(dest='solid', sources=['fluid']),
+            SetWallVelocity(dest='obstacle', sources=['fluid']),
             ], real=False),
 
     # Once the pressure for the fluid phase has been updated, we can

examples/surface_tension/circular_droplet.py

@@ -20,7 +20,7 @@
 from pysph.sph.wc.viscosity import ClearyArtificialViscosity
 
 from pysph.sph.wc.transport_velocity import SummationDensity, MomentumEquationPressureGradient,\
-    SolidWallPressureBC, SolidWallNoSlipBC, ShepardFilteredVelocity, \
+    SolidWallPressureBC, SolidWallNoSlipBC, \
     StateEquation, MomentumEquationArtificialStress, MomentumEquationViscosity
 
 from pysph.sph.surface_tension import ColorGradientUsingNumberDensity, \

examples/surface_tension/khi_tvf.py

@@ -12,7 +12,7 @@
 from pysph.sph.wc.viscosity import ClearyArtificialViscosity
 
 from pysph.sph.wc.transport_velocity import SummationDensity, MomentumEquationPressureGradient,\
-    SolidWallPressureBC, SolidWallNoSlipBC, ShepardFilteredVelocity, \
+    SolidWallPressureBC, SolidWallNoSlipBC, SetWallVelocity, \
     StateEquation, MomentumEquationArtificialStress, MomentumEquationViscosity
 
 from pysph.sph.surface_tension import ColorGradientUsingNumberDensity, \
@@ -95,10 +95,7 @@ def create_particles(**kwargs):
 
         # interface curvature
         'kappa',
-
-        # filtered velocities
-        'uf', 'vf', 'wf',
-
+
         # transport velocities
         'uhat', 'vhat', 'what', 'auhat', 'avhat', 'awhat', 
 
@@ -153,7 +150,16 @@ def create_particles(**kwargs):
     # set additional output arrays for the fluid
     fluid.add_output_arrays(['V', 'color', 'cx', 'cy', 'nx', 'ny', 'ddelta',
                              'kappa', 'N', 'p', 'rho'])
+
+    # extrapolated velocities for the wall
+    for name in ['uf', 'vf', 'wf']:
+        wall.add_property(name)
 
+    # dummy velocities for the wall
+    # required for the no-slip BC
+    for name in ['ug','vg','wg']:
+        wall.add_property(name)
+
     print "2D KHI with %d fluid particles and %d wall particles"%(
             fluid.get_number_of_particles(), wall.get_number_of_particles())
 
@@ -186,13 +192,13 @@ def create_particles(**kwargs):
             ] ),
 
     # Given the updated number density for the fluid, we can update
-    # the fluid pressure. Additionally, we can compute the Shepard
-    # Filtered velocity required for the no-penetration boundary
+    # the fluid pressure. Additionally, we can extrapolate the fluid
+    # velocity to the wall for the no-slip boundary
     # condition. Also compute the smoothed color based on the color
     # index for a particle.
     Group(equations=[
             StateEquation(dest='fluid', sources=None, rho0=rho0, p0=p0),
-            ShepardFilteredVelocity(dest='fluid', sources=['fluid']),
+            SetWallVelocity(dest='wall', sources=['fluid']),
             SmoothedColor( dest='fluid', sources=['fluid'] ),
             ] ),
 

examples/surface_tension/square_droplet.py

@@ -54,8 +54,8 @@
 from pysph.sph.wc.viscosity import ClearyArtificialViscosity
 
 from pysph.sph.wc.transport_velocity import SummationDensity, MomentumEquationPressureGradient,\
-    SolidWallPressureBC, SolidWallNoSlipBC, ShepardFilteredVelocity, \
-    StateEquation, MomentumEquationArtificialStress, MomentumEquationViscosity
+    SolidWallPressureBC, SolidWallNoSlipBC, StateEquation,\
+    MomentumEquationArtificialStress, MomentumEquationViscosity
 
 from pysph.sph.surface_tension import InterfaceCurvatureFromNumberDensity, \
     ShadlooYildizSurfaceTensionForce, CSFSurfaceTensionForce, \
@@ -133,10 +133,7 @@ def create_particles(**kwargs):
 
         # interface curvature
         'kappa',
-
-        # filtered velocities
-        'uf', 'vf', 'wf',
-
+
         # transport velocities
         'uhat', 'vhat', 'what', 'auhat', 'avhat', 'awhat', 
 

examples/transport_velocity/cavity.py

@@ -16,7 +16,7 @@
 from pysph.sph.wc.transport_velocity import SummationDensity,\
     StateEquation, MomentumEquationPressureGradient, MomentumEquationViscosity,\
     MomentumEquationArtificialStress, SolidWallPressureBC, SolidWallNoSlipBC,\
-    ShepardFilteredVelocity
+    SetWallVelocity
 
 # numpy
 import numpy as np
@@ -72,9 +72,14 @@ def create_particles(**kwargs):
     fluid.add_property('V')
     solid.add_property('V' )
 
-    # Shepard filtered velocities for the fluid
+    # extrapolated velocities for the solid
     for name in ['uf', 'vf', 'wf']:
-        fluid.add_property(name)
+        solid.add_property(name)
+
+    # dummy velocities for the solid wall
+    # required for the no-slip BC
+    for name in ['ug', 'vg', 'wg']:
+        solid.add_property(name)
 
     # advection velocities and accelerations
     for name in ('uhat', 'vhat', 'what', 'auhat', 'avhat', 'awhat', 'au', 'av', 'aw'):
@@ -148,12 +153,12 @@ def create_particles(**kwargs):
 
 
     # Once the fluid density is computed, we can use the EOS to set
-    # the fluid pressure. Additionally, the shepard filtered velocity
-    # for the fluid phase is determined.
+    # the fluid pressure. Additionally, the dummy velocity for the
+    # channel is set, which is later used in the no-slip wall BC.
     Group(
         equations=[
             StateEquation(dest='fluid', sources=None, p0=p0, rho0=rho0, b=1.0),
-            ShepardFilteredVelocity(dest='fluid', sources=['fluid']),
+            SetWallVelocity(dest='solid', sources=['fluid']),
             ], real=False),
 
     # Once the pressure for the fluid phase has been updated, we can

examples/transport_velocity/couette.py

@@ -15,7 +15,7 @@
 # the eqations
 from pysph.sph.equation import Group
 from pysph.sph.wc.transport_velocity import (SummationDensity,
-    ShepardFilteredVelocity, StateEquation,
+    SetWallVelocity, StateEquation,
     MomentumEquationPressureGradient, MomentumEquationViscosity,
     MomentumEquationArtificialStress,
     SolidWallPressureBC, SolidWallNoSlipBC)
@@ -26,7 +26,7 @@
 # domain and reference values
 Re = 0.0125
 d = 0.5; Ly = 2*d; Lx = 0.4*Ly
-rho0 = 1.0; nu = 1.0
+rho0 = 1.0; nu = 0.01
 
 # upper wall velocity based on the Reynolds number and channel width
 Vmax = nu*Re/(2*d)
@@ -43,7 +43,7 @@
 dt_viscous = 0.125 * h0**2/nu
 dt_force = 1.0
 
-tf = 2.0
+tf = 100.0
 dt = 0.5 * min(dt_cfl, dt_viscous, dt_force)
 
 def create_particles(**kwargs):
@@ -77,7 +77,7 @@ def create_particles(**kwargs):
     # add requisite properties to the arrays:
     # particle volume
     fluid.add_property('V')
-    channel.add_property('V' )
+    channel.add_property('V')
 
     # advection velocities and accelerations
     for name in ('uhat', 'vhat', 'what', 'auhat', 'avhat', 'awhat', 'au', 'av', 'aw'):
@@ -86,14 +86,18 @@ def create_particles(**kwargs):
     # kernel summation correction for the channel
     channel.add_property('wij')
 
-
     channel.add_property('ax')
     channel.add_property('ay')
     channel.add_property('az')
 
-    # Shepard filtered velocities for the fluid
+    # extrapolated velocities for the channel
     for name in ['uf', 'vf', 'wf']:
-        fluid.add_property(name)
+        channel.add_property(name)
+
+    # dummy velocities for the channel
+    # required for the no-slip BC
+    for name in ['ug','vg','wg']:
+        channel.add_property(name)
 
     # magnitude of velocity
     fluid.add_property('vmag2')
@@ -157,12 +161,12 @@ def create_particles(**kwargs):
             ], real=False),
 
     # Once the fluid density is computed, we can use the EOS to set
-    # the fluid pressure. Additionally, the shepard filtered velocity
-    # for the fluid phase is determined.
+    # the fluid pressure. Additionally, the dummy velocity for the
+    # channel is set, which is later used in the no-slip wall BC.
     Group(
         equations=[
             StateEquation(dest='fluid', sources=None, p0=p0, rho0=rho0, b=1.0),
-            ShepardFilteredVelocity(dest='fluid', sources=['fluid']),
+            SetWallVelocity(dest='channel', sources=['fluid']),
             ], real=False),
 
     # Once the pressure for the fluid phase has been updated, we can

examples/transport_velocity/lattice_cylinders.py

@@ -15,7 +15,7 @@
 # the eqations
 from pysph.sph.equation import Group
 from pysph.sph.wc.transport_velocity import (SummationDensity,
-    ShepardFilteredVelocity, StateEquation,
+    SetWallVelocity, StateEquation,
     MomentumEquationPressureGradient, MomentumEquationViscosity,
     MomentumEquationArtificialStress,
     SolidWallPressureBC, SolidWallNoSlipBC)
@@ -90,12 +90,17 @@ def create_particles(**kwargs):
     solid.add_property('ay')
     solid.add_property('az')
 
-    # Shepard filtered velocities for the fluid
+    # extrapolated velocities for the solid
     for name in ['uf', 'vf', 'wf']:
-        fluid.add_property(name)
+        solid.add_property(name)
+
+    # dummy velocities for the solid wall
+    # required for the no-slip BC
+    for name in ['ug', 'vg', 'wg']:
+        solid.add_property(name)
 
     # magnitude of velocity
-    fluid.add_property('vmag')
+    fluid.add_property('vmag2')
 
     # density acceleration
     fluid.add_property('arho')
@@ -152,12 +157,12 @@ def create_particles(**kwargs):
 
 
     # Once the fluid density is computed, we can use the EOS to set
-    # the fluid pressure. Additionally, the shepard filtered velocity
-    # for the fluid phase is determined.
+    # the fluid pressure. Additionally, the dummy velocity for the
+    # channel is set, which is later used in the no-slip wall BC.
     Group(
         equations=[
             StateEquation(dest='fluid', sources=None, p0=p0, rho0=rho0, b=1.0),
-            ShepardFilteredVelocity(dest='fluid', sources=['fluid']),
+            SetWallVelocity(dest='solid', sources=['fluid']),
             ], real=False),
 
     # Once the pressure for the fluid phase has been updated, we can

examples/transport_velocity/periodic_cylinders.py

@@ -15,7 +15,7 @@
 # the eqations
 from pysph.sph.equation import Group
 from pysph.sph.wc.transport_velocity import (SummationDensity,
-    ShepardFilteredVelocity, StateEquation,
+    SetWallVelocity, StateEquation,
     MomentumEquationPressureGradient, MomentumEquationViscosity,
     MomentumEquationArtificialStress,
     SolidWallPressureBC, SolidWallNoSlipBC)
@@ -79,9 +79,9 @@ def create_particles(**kwargs):
     fluid.add_property('V')
     solid.add_property('V' )
 
-    # Shepard filtered velocities for the fluid
+    # extrapolated velocities for the solid
     for name in ['uf', 'vf', 'wf']:
-        fluid.add_property(name)
+        solid.add_property(name)
 
     # advection velocities and accelerations for the fluid
     for name in ('uhat', 'vhat', 'what', 'auhat', 'avhat', 'awhat'):
@@ -90,6 +90,11 @@ def create_particles(**kwargs):
     # kernel summation correction for the solid
     solid.add_property('wij')
 
+    # dummy velocities for the solid walls
+    # required for the no-slip BC
+    for name in ['ug', 'vg', 'wg']:
+        solid.add_property(name)
+
     # imposed accelerations on the solid
     solid.add_property('ax')
     solid.add_property('ay')
@@ -156,12 +161,12 @@ def create_particles(**kwargs):
             ], real=False),
 
     # Once the fluid density is computed, we can use the EOS to set
-    # the fluid pressure. Additionally, the shepard filtered velocity
-    # for the fluid phase is determined.
+    # the fluid pressure. Additionally, the dummy velocity for the
+    # channel is set, which is later used in the no-slip wall BC.
     Group(
         equations=[
             StateEquation(dest='fluid', sources=None, p0=p0, rho0=rho0, b=1.0),
-            ShepardFilteredVelocity(dest='fluid', sources=['fluid']),
+            SetWallVelocity(dest='solid', sources=['fluid']),
             ], real=False),
 
     # Once the pressure for the fluid phase has been updated, we can

examples/transport_velocity/poiseuille.py

@@ -15,7 +15,7 @@
 # the eqations
 from pysph.sph.equation import Group
 from pysph.sph.wc.transport_velocity import (SummationDensity,
-    ShepardFilteredVelocity, StateEquation,
+    SetWallVelocity, StateEquation,
     MomentumEquationPressureGradient, MomentumEquationViscosity,
     MomentumEquationArtificialStress,
     SolidWallPressureBC, SolidWallNoSlipBC)
@@ -94,9 +94,14 @@ def create_particles(**kwargs):
     channel.add_property('ay')
     channel.add_property('az')
 
-    # Shepard filtered velocities for the fluid
+    # extrapolated velocities for the channel
     for name in ['uf', 'vf', 'wf']:
-        fluid.add_property(name)
+        channel.add_property(name)
+
+    # dummy velocities for the channel
+    # required for the no-slip BC
+    for name in ['ug', 'vg', 'wg']:
+        channel.add_property(name)
 
     # magnitude of velocity
     fluid.add_property('vmag2')
@@ -154,12 +159,12 @@ def create_particles(**kwargs):
             ], real=False),
 
     # Once the fluid density is computed, we can use the EOS to set
-    # the fluid pressure. Additionally, the shepard filtered velocity
-    # for the fluid phase is determined.
+    # the fluid pressure. Additionally, the dummy velocity for the
+    # channel is set, which is later used in the no-slip wall BC.
     Group(
         equations=[
             StateEquation(dest='fluid', sources=None, p0=p0, rho0=rho0, b=1.0),
-            ShepardFilteredVelocity(dest='fluid', sources=['fluid']),
+            SetWallVelocity(dest='channel', sources=['fluid']),
             ], real=False),
 
     # Once the pressure for the fluid phase has been updated, we can