#*------------------------------------------------------------------------------*
#* 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_reconstruction import SpatialReconstruction
[docs]
class WENO5Z(SpatialReconstruction):
''' Borges et al. - 2008 - An improved WENO scheme for hyperbolic conservation laws '''
def __init__(self, nh: int, inactive_axis: List) -> None:
super(WENO5Z, self).__init__(nh=nh, inactive_axis=inactive_axis)
self.dr_ = [
[1/10, 6/10, 3/10],
[3/10, 6/10, 1/10],
]
self.cr_ = [
[[1/3, -7/6, 11/6], [-1/6, 5/6, 1/3], [1/3, 5/6, -1/6]],
[[-1/6, 5/6, 1/3], [1/3, 5/6, -1/6], [11/6, -7/6, 1/3]],
]
self._stencil_size = 6
self._slices = [
[
[ jnp.s_[..., self.n-3+j:-self.n-2+j, self.nhy, self.nhz],
jnp.s_[..., self.n-2+j:-self.n-1+j, self.nhy, self.nhz],
jnp.s_[..., self.n-1+j:-self.n+j , self.nhy, self.nhz],
jnp.s_[..., self.n+j :-self.n+1+j, self.nhy, self.nhz],
jnp.s_[..., self.n+1+j:-self.n+2+j, self.nhy, self.nhz], ],
[ jnp.s_[..., self.nhx, self.n-3+j:-self.n-2+j, 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+j , self.nhz],
jnp.s_[..., self.nhx, self.n+j :-self.n+1+j, self.nhz],
jnp.s_[..., self.nhx, self.n+1+j:-self.n+2+j, self.nhz], ],
[ jnp.s_[..., self.nhx, self.nhy, self.n-3+j:-self.n-2+j],
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+j ],
jnp.s_[..., self.nhx, self.nhy, self.n+j :-self.n+1+j],
jnp.s_[..., self.nhx, self.nhy, self.n+1+j:-self.n+2+j], ]
] for j in range(2)]
[docs]
def set_slices_stencil(self) -> None:
self._slices = [
[
[ jnp.s_[..., 0+j, None:None, None:None],
jnp.s_[..., 1+j, None:None, None:None],
jnp.s_[..., 2+j, None:None, None:None],
jnp.s_[..., 3+j, None:None, None:None],
jnp.s_[..., 4+j, None:None, None:None], ],
[ jnp.s_[..., None:None, 0+j, None:None],
jnp.s_[..., None:None, 1+j, None:None],
jnp.s_[..., None:None, 2+j, None:None],
jnp.s_[..., None:None, 3+j, None:None],
jnp.s_[..., None:None, 4+j, None:None], ],
[ jnp.s_[..., None:None, None:None, 0+j],
jnp.s_[..., None:None, None:None, 1+j],
jnp.s_[..., None:None, None:None, 2+j],
jnp.s_[..., None:None, None:None, 3+j],
jnp.s_[..., None:None, None:None, 4+j], ],
] for j in range(2) ]
[docs]
def reconstruct_xi(self, buffer: jnp.ndarray, axis: int, j: int, dx: float = None, **kwargs) -> jnp.ndarray:
s1_ = self._slices[j][axis]
beta_0 = 13.0 / 12.0 * (buffer[s1_[0]] - 2 * buffer[s1_[1]] + buffer[s1_[2]]) * (buffer[s1_[0]] - 2 * buffer[s1_[1]] + buffer[s1_[2]]) \
+ 1.0 / 4.0 * (buffer[s1_[0]] - 4 * buffer[s1_[1]] + 3 * buffer[s1_[2]]) * (buffer[s1_[0]] - 4 * buffer[s1_[1]] + 3 * buffer[s1_[2]])
beta_1 = 13.0 / 12.0 * (buffer[s1_[1]] - 2 * buffer[s1_[2]] + buffer[s1_[3]]) * (buffer[s1_[1]] - 2 * buffer[s1_[2]] + buffer[s1_[3]]) \
+ 1.0 / 4.0 * (buffer[s1_[1]] - buffer[s1_[3]]) * (buffer[s1_[1]] - buffer[s1_[3]])
beta_2 = 13.0 / 12.0 * (buffer[s1_[2]] - 2 * buffer[s1_[3]] + buffer[s1_[4]]) * (buffer[s1_[2]] - 2 * buffer[s1_[3]] + buffer[s1_[4]]) \
+ 1.0 / 4.0 * (3 * buffer[s1_[2]] - 4 * buffer[s1_[3]] + buffer[s1_[4]]) * (3 * buffer[s1_[2]] - 4 * buffer[s1_[3]] + buffer[s1_[4]])
tau_5 = jnp.abs(beta_0 - beta_2)
alpha_z_0 = self.dr_[j][0] * (1.0 + tau_5 / (beta_0 + self.eps) )
alpha_z_1 = self.dr_[j][1] * (1.0 + tau_5 / (beta_1 + self.eps) )
alpha_z_2 = self.dr_[j][2] * (1.0 + tau_5 / (beta_2 + self.eps) )
one_alpha_z = 1.0 / (alpha_z_0 + alpha_z_1 + alpha_z_2)
omega_z_0 = alpha_z_0 * one_alpha_z
omega_z_1 = alpha_z_1 * one_alpha_z
omega_z_2 = alpha_z_2 * one_alpha_z
p_0 = self.cr_[j][0][0] * buffer[s1_[0]] + self.cr_[j][0][1] * buffer[s1_[1]] + self.cr_[j][0][2] * buffer[s1_[2]]
p_1 = self.cr_[j][1][0] * buffer[s1_[1]] + self.cr_[j][1][1] * buffer[s1_[2]] + self.cr_[j][1][2] * buffer[s1_[3]]
p_2 = self.cr_[j][2][0] * buffer[s1_[2]] + self.cr_[j][2][1] * buffer[s1_[3]] + self.cr_[j][2][2] * buffer[s1_[4]]
cell_state_xi_j = omega_z_0 * p_0 + omega_z_1 * p_1 + omega_z_2 * p_2
return cell_state_xi_j