#*------------------------------------------------------------------------------*
#* JAX-FLUIDS - *
#* *
#* A fully-differentiable CFD solver for compressible two-phase flows. *
#* Copyright (C) 2022 Deniz A. Bezgin, Aaron B. Buhendwa, Nikolaus A. Adams *
#* *
#* This program is free software: you can redistribute it and/or modify *
#* it under the terms of the GNU General Public License as published by *
#* the Free Software Foundation, either version 3 of the License, or *
#* (at your option) any later version. *
#* *
#* This program is distributed in the hope that it will be useful, *
#* but WITHOUT ANY WARRANTY; without even the implied warranty of *
#* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
#* GNU General Public License for more details. *
#* *
#* You should have received a copy of the GNU General Public License *
#* along with this program. If not, see <https://www.gnu.org/licenses/>. *
#* *
#*------------------------------------------------------------------------------*
#* *
#* CONTACT *
#* *
#* deniz.bezgin@tum.de // aaron.buhendwa@tum.de // nikolaus.adams@tum.de *
#* *
#*------------------------------------------------------------------------------*
#* *
#* Munich, April 15th, 2022 *
#* *
#*------------------------------------------------------------------------------*
from typing import List
import jax.numpy as jnp
from jaxfluids.stencils.spatial_derivative import SpatialDerivative
from jaxfluids.stencils.levelset.deriv_first_order import DerivativeFirstOrderSided
[docs]
class WENO3DERIV(SpatialDerivative):
def __init__(self, nh: int, inactive_axis: List, face_value: str = "right"):
offset = 2
super(WENO3DERIV, self).__init__(offset, inactive_axis)
self.derivative_stencil = DerivativeFirstOrderSided(nh, inactive_axis, offset)
self.dr_ = [
[1/3, 2/3],
[2/3, 1/3],
]
self.cr_ = [
[[-0.5, 1.5], [0.5, 0.5]],
[[0.5, 0.5], [1.5, -0.5]],
]
self._slices = [
[
[ jnp.s_[..., self.n-2+j:-self.n-1+j, self.nhy, self.nhz],
jnp.s_[..., self.n-1+j:-self.n+0+j, self.nhy, self.nhz],
jnp.s_[..., jnp.s_[self.n+0+j:-self.n+1+j] if -self.n+1+j != 0 else jnp.s_[self.n+0+j:None], self.nhy, self.nhz], ],
[ jnp.s_[..., self.nhx, self.n-2+j:-self.n-1+j, self.nhz],
jnp.s_[..., self.nhx, self.n-1+j:-self.n+0+j, self.nhz],
jnp.s_[..., self.nhx, jnp.s_[self.n+0+j:-self.n+1+j] if -self.n+1+j != 0 else jnp.s_[self.n+0+j:None], self.nhz], ],
[ jnp.s_[..., self.nhx, self.nhy, self.n-2+j:-self.n-1+j],
jnp.s_[..., self.nhx, self.nhy, self.n-1+j:-self.n+0+j],
jnp.s_[..., self.nhx, self.nhy, jnp.s_[self.n+0+j:-self.n+1+j] if -self.n+1+j != 0 else jnp.s_[self.n+0+j:None]], ],
] for j in range(2)]
if face_value == "right":
self.return_indices = [jnp.s_[...,1:,:,:], jnp.s_[...,:,1:,:], jnp.s_[...,:,:,1:]]
self.sided_deriv_upwind = 0
elif face_value == "left":
self.return_indices = [jnp.s_[...,:-1,:,:], jnp.s_[...,:,:-1,:], jnp.s_[...,:,:,:-1]]
self.sided_deriv_upwind = 1
else:
assert False, "WENO3DERIV face_value must be left or right"
[docs]
def derivative_xi(self, levelset: jnp.ndarray, dx: float, i: int, j: int, *args) -> jnp.ndarray:
levelset = self.derivative_stencil.derivative_xi(levelset, dx, i, j=self.sided_deriv_upwind)
s1_ = self._slices[j][i]
beta_0 = (levelset[s1_[1]] - levelset[s1_[0]]) * (levelset[s1_[1]] - levelset[s1_[0]])
beta_1 = (levelset[s1_[2]] - levelset[s1_[1]]) * (levelset[s1_[2]] - levelset[s1_[1]])
one_beta_0_sq = 1.0 / ((self.eps + beta_0) * (self.eps + beta_0))
one_beta_1_sq = 1.0 / ((self.eps + beta_1) * (self.eps + beta_1))
alpha_0 = self.dr_[j][0] * one_beta_0_sq
alpha_1 = self.dr_[j][1] * one_beta_1_sq
one_alpha = 1.0 / (alpha_0 + alpha_1)
omega_0 = alpha_0 * one_alpha
omega_1 = alpha_1 * one_alpha
p_0 = self.cr_[j][0][0] * levelset[s1_[0]] + self.cr_[j][0][1] * levelset[s1_[1]]
p_1 = self.cr_[j][1][0] * levelset[s1_[1]] + self.cr_[j][1][1] * levelset[s1_[2]]
cell_state_xi_j = omega_0 * p_0 + omega_1 * p_1
return cell_state_xi_j[self.return_indices[i]]