Add docs for no slip conditions

src/schemes/boundary/dummy_particles/dummy_particles.jl

@@ -4,21 +4,6 @@
                                 smoothing_length; viscosity=NoViscosity(),
                                 state_equation=nothing, correction=nothing)
 
-## Arguments
-- `initial_density`: Vector holding the initial density of each boundary particles
-- `hydrodynamic_mass`: Vector holding the "hydrodynamic mass" of each boundary particles
-- `density_calculator`: Option to compute the hydrodynamic boundary density. For more
-                        information see description below.
-- `smoothing_kernel`: Smoothing kernel should be the same as for the adjacent fluid system
-- `smoothing_length`: Smoothing length should be the same as for the adjacent fluid system
-
-# Keywords
-- `state_equation`: This should be the same as for the adjacent fluid system
-                    (see e.g. [`StateEquationCole`](@ref)).
-- `correction`:     Correction method of the adjacent fluid system (see [Corrections](@ref corrections)).
-- `viscosity`:      Slip (default) or no-slip condition. See description below for further
-                    information
-
 Boundaries modeled as dummy particles, which are treated like fluid particles,
 but their positions and velocities are not evolved in time. Since the force towards the fluid
 should not change with the material density when used with a [`TotalLagrangianSPHSystem`](@ref), the
@@ -77,8 +62,8 @@ We provide five options to compute the boundary density and pressure, determined
 
 ## No-slip conditions
 
-For the interaction of dummy particles and fluid particles, Adami (Adami et al. 2012)
-imposes a no-slip boundary condition by assigning a wall velocity ``v_w`` to the dummy particle.
+For the interaction of dummy particles and fluid particles, Adami et al. (2012)
+impose a no-slip boundary condition by assigning a wall velocity ``v_w`` to the dummy particle.
 
 The wall velocity of particle ``a`` is calculated from the prescribed boundary particle
 velocity ``v_a`` and the smoothed velocity field
@@ -87,9 +72,28 @@ v_w = 2 v_a - \frac{\sum_b v_b W_{ab}}{\sum_b W_{ab}},
 ```
 where the sum is over all fluid particles.
 
-By choosing the viscosity model [`ViscosityAdami`](@ref) for `viscosity`, a non-slip
-condition is imposed. When omitting the viscous interaction
-(default `viscosity=NoViscosity()`), a free-slip wall boundary condition is applied.
+By choosing the viscosity model [`ViscosityAdami`](@ref) for `viscosity`, a no-slip
+condition is imposed. It is recommended to choose `nu` in the order of either the kinematic
+viscosity parameter of the adjacent fluid or the equivalent from the artificial parameter
+`alpha` of the adjacent fluid (``\nu = \frac{\alpha h c }{2d + 4}``). When omitting the
+viscous interaction (default `viscosity=NoViscosity()`), a free-slip wall boundary
+condition is applied.
+
+# Arguments
+- `initial_density`: Vector holding the initial density of each boundary particle
+- `hydrodynamic_mass`: Vector holding the "hydrodynamic mass" of each boundary particle.
+                       See description above for more information.
+- `density_calculator`: Strategy to compute the hydrodynamic density of the boundary particles.
+                        See description above for more information.
+- `smoothing_kernel`: Smoothing kernel should be the same as for the adjacent fluid system
+- `smoothing_length`: Smoothing length should be the same as for the adjacent fluid system
+
+# Keywords
+- `state_equation`: This should be the same as for the adjacent fluid system
+                    (see e.g. [`StateEquationCole`](@ref)).
+- `correction`:     Correction method of the adjacent fluid system (see [Corrections](@ref corrections)).
+- `viscosity`:      Slip (default) or no-slip condition. See description above for further
+                    information.
 
 # Examples
 
@@ -98,7 +102,7 @@ condition is imposed. When omitting the viscous interaction
 boundary_model = BoundaryModelDummyParticles(densities, masses, AdamiPressureExtrapolation(),
                                              smoothing_kernel, smoothing_length))
 
-# No slip condition
+# No-slip condition
 boundary_model = BoundaryModelDummyParticles(densities, masses, AdamiPressureExtrapolation(),
                                              smoothing_kernel, smoothing_length),
                                              viscosity=ViscosityAdami(nu))

src/schemes/boundary/monaghan_kajtar/monaghan_kajtar.jl

@@ -1,15 +1,6 @@
 @doc raw"""
     BoundaryModelMonaghanKajtar(K, beta, boundary_particle_spacing, mass;
                                 viscosity=NoViscosity())
-## Arguments
-- `K`: Scaling factor for repulsive force.
-- `beta`: Ratio of fluid particle spacing to boundary particle spacing.
-- `boundary_particle_spacing`: Boundary particle spacing.
-- `mass`: Vector holding the mass of each boundary particles.
-
-# Keywords
-- `viscosity`:  Slip (default) or no-slip condition. See description below for further
-                information
 
 Boundaries modeled as boundary particles which exert forces on the fluid particles (Monaghan, Kajtar, 2009).
 The force on fluid particle ``a`` due to boundary particle ``b`` is given by
@@ -52,12 +43,22 @@ The viscosity ``\Pi_{ab}`` is calculated according to the viscosity used in the
 simulation, where the density of the boundary particle if needed is assumed to be
 identical to the density of the fluid particle.
 
-# No slip condition
+# No-slip condition
 
 By choosing the viscosity model [`ArtificialViscosityMonaghan`](@ref) for `viscosity`,
-a non-slip condition is imposed. When omitting the viscous interaction
+a no-slip condition is imposed. When omitting the viscous interaction
 (default `viscosity=NoViscosity()`), a free-slip wall boundary condition is applied.
 
+# Arguments
+- `K`: Scaling factor for repulsive force.
+- `beta`: Ratio of fluid particle spacing to boundary particle spacing.
+- `boundary_particle_spacing`: Boundary particle spacing.
+- `mass`: Vector holding the mass of each boundary particle.
+
+# Keywords
+- `viscosity`:  Free-slip (default) or no-slip condition. See description above for further
+                information.
+
 !!! warning
     The no-slip conditions for `BoundaryModelMonaghanKajtar` have not been verified yet.
 

src/schemes/fluid/viscosity.jl

@@ -38,8 +38,9 @@ and ``\bar{\rho}_{ab}`` is the arithmetic mean of their densities.
 Note that ``\alpha`` needs to adjusted for different resolutions to maintain a specific Reynolds Number.
 To do so, Monaghan (Monaghan 2005) defined an equivalent effective physical kinematic viscosity ``\nu`` by
 ```math
-\nu = \frac{\alpha h c }{\rho_{ab}}.
+    \nu = \frac{\alpha h c }{2d + 4},
 ```
+where ``d`` is the dimension.
 
 ## References:
 - Joseph J. Monaghan. "Smoothed Particle Hydrodynamics".