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#[cfg(feature = "parallel")]
use rayon::prelude::*;
use crate::geometry::ParticlesContacts;
use crate::math::{Real, Vector};
use crate::object::{Boundary, Fluid};
use crate::solver::NonPressureForce;
use crate::TimestepManager;
pub struct He2014SurfaceTension {
fluid_tension_coefficient: Real,
boundary_tension_coefficient: Real,
gradcs: Vec<Real>,
colors: Vec<Real>,
}
impl He2014SurfaceTension {
pub fn new(fluid_tension_coefficient: Real, boundary_tension_coefficient: Real) -> Self {
Self {
fluid_tension_coefficient,
boundary_tension_coefficient,
colors: Vec::new(),
gradcs: Vec::new(),
}
}
fn init(&mut self, fluid: &Fluid) {
if self.gradcs.len() != fluid.num_particles() {
self.gradcs
.resize(fluid.num_particles(), na::zero::<Real>());
self.colors
.resize(fluid.num_particles(), na::zero::<Real>());
}
}
fn compute_colors(
&mut self,
fluid_fluid_contacts: &ParticlesContacts,
fluid_boundary_contacts: &ParticlesContacts,
fluid: &Fluid,
boundaries: &[Boundary],
densities: &[Real],
) {
par_iter_mut!(self.colors)
.enumerate()
.for_each(|(i, color_i)| {
let mut color = na::zero::<Real>();
for c in fluid_fluid_contacts
.particle_contacts(i)
.read()
.unwrap()
.iter()
{
if c.i_model == c.j_model {
color += c.weight * fluid.particle_mass(c.j) / densities[c.j];
}
}
for c in fluid_boundary_contacts
.particle_contacts(i)
.read()
.unwrap()
.iter()
{
color += c.weight * boundaries[c.j_model].volumes[c.j];
}
*color_i = color;
})
}
fn compute_gradc(
&mut self,
fluid_fluid_contacts: &ParticlesContacts,
fluid: &Fluid,
densities: &[Real],
) {
let colors = &self.colors;
par_iter_mut!(self.gradcs)
.enumerate()
.for_each(|(i, gradc_i)| {
let mut gradc = Vector::zeros();
let _denom = na::zero::<Real>();
for c in fluid_fluid_contacts
.particle_contacts(i)
.read()
.unwrap()
.iter()
{
if c.i_model == c.j_model {
gradc +=
c.gradient * colors[c.j] * fluid.particle_mass(c.j) / densities[c.j];
}
}
*gradc_i = (gradc / colors[i]).norm_squared();
})
}
}
impl NonPressureForce for He2014SurfaceTension {
fn solve(
&mut self,
_timestep: &TimestepManager,
_kernel_radius: Real,
fluid_fluid_contacts: &ParticlesContacts,
fluid_boundary_contacts: &ParticlesContacts,
fluid: &mut Fluid,
boundaries: &[Boundary],
densities: &[Real],
) {
self.init(fluid);
let _2: Real = na::convert::<_, Real>(2.0f64);
self.compute_colors(
fluid_fluid_contacts,
fluid_boundary_contacts,
fluid,
boundaries,
densities,
);
self.compute_gradc(fluid_fluid_contacts, fluid, densities);
let gradcs = &self.gradcs;
let fluid_tension_coefficient = self.fluid_tension_coefficient;
let boundary_tension_coefficient = self.boundary_tension_coefficient;
let density0 = fluid.density0;
let volumes = &fluid.volumes;
par_iter_mut!(fluid.accelerations)
.enumerate()
.for_each(|(i, acceleration_i)| {
let mi = volumes[i] * density0;
if fluid_tension_coefficient != na::zero::<Real>() {
for c in fluid_fluid_contacts
.particle_contacts(i)
.read()
.unwrap()
.iter()
{
if c.i_model == c.j_model {
let mj = volumes[c.j] * density0;
let gradsum = gradcs[c.i] + gradcs[c.j];
let f = c.gradient
* (mi / densities[c.i] * mj / densities[c.j] * gradsum / _2);
*acceleration_i += f * (fluid_tension_coefficient / (_2 * mi));
}
}
}
if boundary_tension_coefficient != na::zero::<Real>() {
for c in fluid_boundary_contacts
.particle_contacts(i)
.read()
.unwrap()
.iter()
{
let mj = boundaries[c.j_model].volumes[c.j] * density0;
let gradsum = gradcs[c.i];
let f = c.gradient
* (mi / densities[c.i] * mj / density0
* gradsum
* boundary_tension_coefficient
* na::convert::<_, Real>(0.25));
*acceleration_i += f / mi;
boundaries[c.j_model].apply_force(c.j, -f);
}
}
})
}
fn apply_permutation(&mut self, _: &[usize]) {}
}