def evolve(self, dt):
"""
Evolve the incompressible equations through one timestep.
"""
u = self.cc_data.get_var("x-velocity")
v = self.cc_data.get_var("y-velocity")
gradp_x = self.cc_data.get_var("gradp_x")
gradp_y = self.cc_data.get_var("gradp_y")
phi = self.cc_data.get_var("phi")
myg = self.cc_data.grid
dtdx = dt / myg.dx
dtdy = dt / myg.dy
#---------------------------------------------------------------------
# create the limited slopes of u and v (in both directions)
#---------------------------------------------------------------------
limiter = self.rp.get_param("incompressible.limiter")
if (limiter == 0): limitFunc = reconstruction_f.nolimit
elif (limiter == 1): limitFunc = reconstruction_f.limit2
else: limitFunc = reconstruction_f.limit4
ldelta_ux = limitFunc(1, u, myg.qx, myg.qy, myg.ng)
ldelta_vx = limitFunc(1, v, myg.qx, myg.qy, myg.ng)
ldelta_uy = limitFunc(2, u, myg.qx, myg.qy, myg.ng)
ldelta_vy = limitFunc(2, v, myg.qx, myg.qy, myg.ng)
#---------------------------------------------------------------------
# get the advective velocities
#---------------------------------------------------------------------
"""
the advective velocities are the normal velocity through each cell
interface, and are defined on the cell edges, in a MAC type
staggered form
n+1/2
v
i,j+1/2
+------+------+
| |
n+1/2 | | n+1/2
u + U + u
i-1/2,j | i,j | i+1/2,j
| |
+------+------+
n+1/2
v
i,j-1/2
"""
# this returns u on x-interfaces and v on y-interfaces. These
# constitute the MAC grid
print(" making MAC velocities")
u_MAC, v_MAC = incomp_interface_f.mac_vels(myg.qx, myg.qy, myg.ng,
myg.dx, myg.dy, dt, u, v,
ldelta_ux, ldelta_vx,
ldelta_uy, ldelta_vy,
gradp_x, gradp_y)
#---------------------------------------------------------------------
# do a MAC projection ot make the advective velocities divergence
# free
#---------------------------------------------------------------------
# we will solve L phi = D U^MAC, where phi is cell centered, and
# U^MAC is the MAC-type staggered grid of the advective
# velocities.
print(" MAC projection")
# create the multigrid object
mg = MG.CellCenterMG2d(myg.nx,
myg.ny,
xl_BC_type=self.cc_data.BCs["phi-MAC"].xlb,
xr_BC_type=self.cc_data.BCs["phi-MAC"].xrb,
yl_BC_type=self.cc_data.BCs["phi-MAC"].ylb,
yr_BC_type=self.cc_data.BCs["phi-MAC"].yrb,
xmin=myg.xmin,
xmax=myg.xmax,
ymin=myg.ymin,
ymax=myg.ymax,
verbose=0)
# first compute divU
divU = mg.soln_grid.scratch_array()
# MAC velocities are edge-centered. divU is cell-centered.
divU[mg.ilo:mg.ihi+1,mg.jlo:mg.jhi+1] = \
(u_MAC[myg.ilo+1:myg.ihi+2,myg.jlo:myg.jhi+1] -
u_MAC[myg.ilo :myg.ihi+1,myg.jlo:myg.jhi+1])/myg.dx + \
(v_MAC[myg.ilo:myg.ihi+1,myg.jlo+1:myg.jhi+2] -
v_MAC[myg.ilo:myg.ihi+1,myg.jlo :myg.jhi+1])/myg.dy
# solve the Poisson problem
mg.init_zeros()
mg.init_RHS(divU)
mg.solve(rtol=1.e-12)
# update the normal velocities with the pressure gradient -- these
# constitute our advective velocities
phi_MAC = self.cc_data.get_var("phi-MAC")
solution = mg.get_solution()
phi_MAC[myg.ilo-1:myg.ihi+2,myg.jlo-1:myg.jhi+2] = \
solution[mg.ilo-1:mg.ihi+2,mg.jlo-1:mg.jhi+2]
# we need the MAC velocities on all edges of the computational domain
u_MAC[myg.ilo:myg.ihi+2,myg.jlo:myg.jhi+1] -= \
(phi_MAC[myg.ilo :myg.ihi+2,myg.jlo:myg.jhi+1] -
phi_MAC[myg.ilo-1:myg.ihi+1,myg.jlo:myg.jhi+1])/myg.dx
v_MAC[myg.ilo:myg.ihi+1,myg.jlo:myg.jhi+2] -= \
(phi_MAC[myg.ilo:myg.ihi+1,myg.jlo :myg.jhi+2] -
phi_MAC[myg.ilo:myg.ihi+1,myg.jlo-1:myg.jhi+1])/myg.dy
#---------------------------------------------------------------------
# recompute the interface states, using the advective velocity
# from above
#---------------------------------------------------------------------
print(" making u, v edge states")
u_xint, v_xint, u_yint, v_yint = \
incomp_interface_f.states(myg.qx, myg.qy, myg.ng,
myg.dx, myg.dy, dt,
u, v,
ldelta_ux, ldelta_vx,
ldelta_uy, ldelta_vy,
gradp_x, gradp_y,
u_MAC, v_MAC)
#---------------------------------------------------------------------
# update U to get the provisional velocity field
#---------------------------------------------------------------------
print(" doing provisional update of u, v")
# compute (U.grad)U
# we want u_MAC U_x + v_MAC U_y
advect_x = myg.scratch_array()
advect_y = myg.scratch_array()
advect_x[myg.ilo:myg.ihi+1,myg.jlo:myg.jhi+1] = \
0.5*(u_MAC[myg.ilo :myg.ihi+1,myg.jlo:myg.jhi+1] +
u_MAC[myg.ilo+1:myg.ihi+2,myg.jlo:myg.jhi+1]) * \
(u_xint[myg.ilo+1:myg.ihi+2,myg.jlo:myg.jhi+1] -
u_xint[myg.ilo :myg.ihi+1,myg.jlo:myg.jhi+1])/myg.dx + \
0.5*(v_MAC[myg.ilo:myg.ihi+1,myg.jlo :myg.jhi+1] +
v_MAC[myg.ilo:myg.ihi+1,myg.jlo+1:myg.jhi+2]) * \
(u_yint[myg.ilo:myg.ihi+1,myg.jlo+1:myg.jhi+2] -
u_yint[myg.ilo:myg.ihi+1,myg.jlo :myg.jhi+1])/myg.dy
advect_y[myg.ilo:myg.ihi+1,myg.jlo:myg.jhi+1] = \
0.5*(u_MAC[myg.ilo :myg.ihi+1,myg.jlo:myg.jhi+1] +
u_MAC[myg.ilo+1:myg.ihi+2,myg.jlo:myg.jhi+1]) * \
(v_xint[myg.ilo+1:myg.ihi+2,myg.jlo:myg.jhi+1] -
v_xint[myg.ilo :myg.ihi+1,myg.jlo:myg.jhi+1])/myg.dx + \
0.5*(v_MAC[myg.ilo:myg.ihi+1,myg.jlo :myg.jhi+1] +
v_MAC[myg.ilo:myg.ihi+1,myg.jlo+1:myg.jhi+2]) * \
(v_yint[myg.ilo:myg.ihi+1,myg.jlo+1:myg.jhi+2] -
v_yint[myg.ilo:myg.ihi+1,myg.jlo :myg.jhi+1])/myg.dy
proj_type = self.rp.get_param("incompressible.proj_type")
if (proj_type == 1):
u[:, :] -= (dt * advect_x[:, :] + dt * gradp_x[:, :])
v[:, :] -= (dt * advect_y[:, :] + dt * gradp_y[:, :])
elif (proj_type == 2):
u[:, :] -= dt * advect_x[:, :]
v[:, :] -= dt * advect_y[:, :]
self.cc_data.fill_BC("x-velocity")
self.cc_data.fill_BC("y-velocity")
#---------------------------------------------------------------------
# project the final velocity
#---------------------------------------------------------------------
# now we solve L phi = D (U* /dt)
print(" final projection")
# create the multigrid object
mg = MG.CellCenterMG2d(myg.nx,
myg.ny,
xl_BC_type=self.cc_data.BCs["phi"].xlb,
xr_BC_type=self.cc_data.BCs["phi"].xrb,
yl_BC_type=self.cc_data.BCs["phi"].ylb,
yr_BC_type=self.cc_data.BCs["phi"].yrb,
xmin=myg.xmin,
xmax=myg.xmax,
ymin=myg.ymin,
ymax=myg.ymax,
verbose=0)
# first compute divU
# u/v are cell-centered, divU is cell-centered
divU[mg.ilo:mg.ihi+1,mg.jlo:mg.jhi+1] = \
0.5*(u[myg.ilo+1:myg.ihi+2,myg.jlo:myg.jhi+1] -
u[myg.ilo-1:myg.ihi ,myg.jlo:myg.jhi+1])/myg.dx + \
0.5*(v[myg.ilo:myg.ihi+1,myg.jlo+1:myg.jhi+2] -
v[myg.ilo:myg.ihi+1,myg.jlo-1:myg.jhi ])/myg.dy
mg.init_RHS(divU / dt)
# use the old phi as our initial guess
phiGuess = mg.soln_grid.scratch_array()
phiGuess[mg.ilo-1:mg.ihi+2,mg.jlo-1:mg.jhi+2] = \
phi[myg.ilo-1:myg.ihi+2,myg.jlo-1:myg.jhi+2]
mg.init_solution(phiGuess)
# solve
mg.solve(rtol=1.e-12)
# store the solution
solution = mg.get_solution()
phi[myg.ilo-1:myg.ihi+2,myg.jlo-1:myg.jhi+2] = \
solution[mg.ilo-1:mg.ihi+2,mg.jlo-1:mg.jhi+2]
# compute the cell-centered gradient of p and update the velocities
# this differs depending on what we projected.
gradphi_x = myg.scratch_array()
gradphi_y = myg.scratch_array()
gradphi_x[myg.ilo:myg.ihi+1,myg.jlo:myg.jhi+1] = \
0.5*(phi[myg.ilo+1:myg.ihi+2,myg.jlo:myg.jhi+1] -
phi[myg.ilo-1:myg.ihi ,myg.jlo:myg.jhi+1])/myg.dx
gradphi_y[myg.ilo:myg.ihi+1,myg.jlo:myg.jhi+1] = \
0.5*(phi[myg.ilo:myg.ihi+1,myg.jlo+1:myg.jhi+2] -
phi[myg.ilo:myg.ihi+1,myg.jlo-1:myg.jhi ])/myg.dy
# u = u - grad_x phi dt
u[:, :] -= dt * gradphi_x
v[:, :] -= dt * gradphi_y
# store gradp for the next step
if (proj_type == 1):
gradp_x[:, :] += gradphi_x[:, :]
gradp_y[:, :] += gradphi_y[:, :]
elif (proj_type == 2):
gradp_x[:, :] = gradphi_x[:, :]
gradp_y[:, :] = gradphi_y[:, :]
self.cc_data.fill_BC("x-velocity")
self.cc_data.fill_BC("y-velocity")
def evolve(self, dt):
"""
Evolve the incompressible equations through one timestep.
"""
u = self.cc_data.get_var("x-velocity")
v = self.cc_data.get_var("y-velocity")
gradp_x = self.cc_data.get_var("gradp_x")
gradp_y = self.cc_data.get_var("gradp_y")
phi = self.cc_data.get_var("phi")
myg = self.cc_data.grid
dtdx = dt/myg.dx
dtdy = dt/myg.dy
#---------------------------------------------------------------------
# create the limited slopes of u and v (in both directions)
#---------------------------------------------------------------------
limiter = self.rp.get_param("incompressible.limiter")
if (limiter == 0): limitFunc = reconstruction_f.nolimit
elif (limiter == 1): limitFunc = reconstruction_f.limit2
else: limitFunc = reconstruction_f.limit4
ldelta_ux = limitFunc(1, u, myg.qx, myg.qy, myg.ng)
ldelta_vx = limitFunc(1, v, myg.qx, myg.qy, myg.ng)
ldelta_uy = limitFunc(2, u, myg.qx, myg.qy, myg.ng)
ldelta_vy = limitFunc(2, v, myg.qx, myg.qy, myg.ng)
#---------------------------------------------------------------------
# get the advective velocities
#---------------------------------------------------------------------
"""
the advective velocities are the normal velocity through each cell
interface, and are defined on the cell edges, in a MAC type
staggered form
n+1/2
v
i,j+1/2
+------+------+
| |
n+1/2 | | n+1/2
u + U + u
i-1/2,j | i,j | i+1/2,j
| |
+------+------+
n+1/2
v
i,j-1/2
"""
# this returns u on x-interfaces and v on y-interfaces. These
# constitute the MAC grid
print(" making MAC velocities")
u_MAC, v_MAC = incomp_interface_f.mac_vels(myg.qx, myg.qy, myg.ng,
myg.dx, myg.dy, dt,
u, v,
ldelta_ux, ldelta_vx,
ldelta_uy, ldelta_vy,
gradp_x, gradp_y)
#---------------------------------------------------------------------
# do a MAC projection ot make the advective velocities divergence
# free
#---------------------------------------------------------------------
# we will solve L phi = D U^MAC, where phi is cell centered, and
# U^MAC is the MAC-type staggered grid of the advective
# velocities.
print(" MAC projection")
# create the multigrid object
mg = MG.CellCenterMG2d(myg.nx, myg.ny,
xl_BC_type="periodic",
xr_BC_type="periodic",
yl_BC_type="periodic",
yr_BC_type="periodic",
xmin=myg.xmin, xmax=myg.xmax,
ymin=myg.ymin, ymax=myg.ymax,
verbose=0)
# first compute divU
divU = mg.soln_grid.scratch_array()
# MAC velocities are edge-centered. divU is cell-centered.
divU[mg.ilo:mg.ihi+1,mg.jlo:mg.jhi+1] = \
(u_MAC[myg.ilo+1:myg.ihi+2,myg.jlo:myg.jhi+1] -
u_MAC[myg.ilo :myg.ihi+1,myg.jlo:myg.jhi+1])/myg.dx + \
(v_MAC[myg.ilo:myg.ihi+1,myg.jlo+1:myg.jhi+2] -
v_MAC[myg.ilo:myg.ihi+1,myg.jlo :myg.jhi+1])/myg.dy
# solve the Poisson problem
mg.init_zeros()
mg.init_RHS(divU)
mg.solve(rtol=1.e-12)
# update the normal velocities with the pressure gradient -- these
# constitute our advective velocities
phi_MAC = self.cc_data.get_var("phi-MAC")
solution = mg.get_solution()
phi_MAC[myg.ilo-1:myg.ihi+2,myg.jlo-1:myg.jhi+2] = \
solution[mg.ilo-1:mg.ihi+2,mg.jlo-1:mg.jhi+2]
# we need the MAC velocities on all edges of the computational domain
u_MAC[myg.ilo:myg.ihi+2,myg.jlo:myg.jhi+1] -= \
(phi_MAC[myg.ilo :myg.ihi+2,myg.jlo:myg.jhi+1] -
phi_MAC[myg.ilo-1:myg.ihi+1,myg.jlo:myg.jhi+1])/myg.dx
v_MAC[myg.ilo:myg.ihi+1,myg.jlo:myg.jhi+2] -= \
(phi_MAC[myg.ilo:myg.ihi+1,myg.jlo :myg.jhi+2] -
phi_MAC[myg.ilo:myg.ihi+1,myg.jlo-1:myg.jhi+1])/myg.dy
#---------------------------------------------------------------------
# recompute the interface states, using the advective velocity
# from above
#---------------------------------------------------------------------
print(" making u, v edge states")
u_xint, v_xint, u_yint, v_yint = \
incomp_interface_f.states(myg.qx, myg.qy, myg.ng,
myg.dx, myg.dy, dt,
u, v,
ldelta_ux, ldelta_vx,
ldelta_uy, ldelta_vy,
gradp_x, gradp_y,
u_MAC, v_MAC)
#---------------------------------------------------------------------
# update U to get the provisional velocity field
#---------------------------------------------------------------------
print(" doing provisional update of u, v")
# compute (U.grad)U
# we want u_MAC U_x + v_MAC U_y
advect_x = myg.scratch_array()
advect_y = myg.scratch_array()
advect_x[myg.ilo:myg.ihi+1,myg.jlo:myg.jhi+1] = \
0.5*(u_MAC[myg.ilo :myg.ihi+1,myg.jlo:myg.jhi+1] +
u_MAC[myg.ilo+1:myg.ihi+2,myg.jlo:myg.jhi+1]) * \
(u_xint[myg.ilo+1:myg.ihi+2,myg.jlo:myg.jhi+1] -
u_xint[myg.ilo :myg.ihi+1,myg.jlo:myg.jhi+1])/myg.dx + \
0.5*(v_MAC[myg.ilo:myg.ihi+1,myg.jlo :myg.jhi+1] +
v_MAC[myg.ilo:myg.ihi+1,myg.jlo+1:myg.jhi+2]) * \
(u_yint[myg.ilo:myg.ihi+1,myg.jlo+1:myg.jhi+2] -
u_yint[myg.ilo:myg.ihi+1,myg.jlo :myg.jhi+1])/myg.dy
advect_y[myg.ilo:myg.ihi+1,myg.jlo:myg.jhi+1] = \
0.5*(u_MAC[myg.ilo :myg.ihi+1,myg.jlo:myg.jhi+1] +
u_MAC[myg.ilo+1:myg.ihi+2,myg.jlo:myg.jhi+1]) * \
(v_xint[myg.ilo+1:myg.ihi+2,myg.jlo:myg.jhi+1] -
v_xint[myg.ilo :myg.ihi+1,myg.jlo:myg.jhi+1])/myg.dx + \
0.5*(v_MAC[myg.ilo:myg.ihi+1,myg.jlo :myg.jhi+1] +
v_MAC[myg.ilo:myg.ihi+1,myg.jlo+1:myg.jhi+2]) * \
(v_yint[myg.ilo:myg.ihi+1,myg.jlo+1:myg.jhi+2] -
v_yint[myg.ilo:myg.ihi+1,myg.jlo :myg.jhi+1])/myg.dy
proj_type = self.rp.get_param("incompressible.proj_type")
if (proj_type == 1):
u[:,:] -= (dt*advect_x[:,:] + dt*gradp_x[:,:])
v[:,:] -= (dt*advect_y[:,:] + dt*gradp_y[:,:])
elif (proj_type == 2):
u[:,:] -= dt*advect_x[:,:]
v[:,:] -= dt*advect_y[:,:]
self.cc_data.fill_BC("x-velocity")
self.cc_data.fill_BC("y-velocity")
#---------------------------------------------------------------------
# project the final velocity
#---------------------------------------------------------------------
# now we solve L phi = D (U* /dt)
print(" final projection")
# create the multigrid object
mg = MG.CellCenterMG2d(myg.nx, myg.ny,
xl_BC_type="periodic",
xr_BC_type="periodic",
yl_BC_type="periodic",
yr_BC_type="periodic",
xmin=myg.xmin, xmax=myg.xmax,
ymin=myg.ymin, ymax=myg.ymax,
verbose=0)
# first compute divU
# u/v are cell-centered, divU is cell-centered
divU[mg.ilo:mg.ihi+1,mg.jlo:mg.jhi+1] = \
0.5*(u[myg.ilo+1:myg.ihi+2,myg.jlo:myg.jhi+1] -
u[myg.ilo-1:myg.ihi ,myg.jlo:myg.jhi+1])/myg.dx + \
0.5*(v[myg.ilo:myg.ihi+1,myg.jlo+1:myg.jhi+2] -
v[myg.ilo:myg.ihi+1,myg.jlo-1:myg.jhi ])/myg.dy
mg.init_RHS(divU/dt)
# use the old phi as our initial guess
phiGuess = mg.soln_grid.scratch_array()
phiGuess[mg.ilo-1:mg.ihi+2,mg.jlo-1:mg.jhi+2] = \
phi[myg.ilo-1:myg.ihi+2,myg.jlo-1:myg.jhi+2]
mg.init_solution(phiGuess)
# solve
mg.solve(rtol=1.e-12)
# store the solution
solution = mg.get_solution()
phi[myg.ilo-1:myg.ihi+2,myg.jlo-1:myg.jhi+2] = \
solution[mg.ilo-1:mg.ihi+2,mg.jlo-1:mg.jhi+2]
# compute the cell-centered gradient of p and update the velocities
# this differs depending on what we projected.
gradphi_x = myg.scratch_array()
gradphi_y = myg.scratch_array()
gradphi_x[myg.ilo:myg.ihi+1,myg.jlo:myg.jhi+1] = \
0.5*(phi[myg.ilo+1:myg.ihi+2,myg.jlo:myg.jhi+1] -
phi[myg.ilo-1:myg.ihi ,myg.jlo:myg.jhi+1])/myg.dx
gradphi_y[myg.ilo:myg.ihi+1,myg.jlo:myg.jhi+1] = \
0.5*(phi[myg.ilo:myg.ihi+1,myg.jlo+1:myg.jhi+2] -
phi[myg.ilo:myg.ihi+1,myg.jlo-1:myg.jhi ])/myg.dy
# u = u - grad_x phi dt
u[:,:] -= dt*gradphi_x
v[:,:] -= dt*gradphi_y
# store gradp for the next step
if (proj_type == 1):
gradp_x[:,:] += gradphi_x[:,:]
gradp_y[:,:] += gradphi_y[:,:]
elif (proj_type == 2):
gradp_x[:,:] = gradphi_x[:,:]
gradp_y[:,:] = gradphi_y[:,:]
self.cc_data.fill_BC("x-velocity")
self.cc_data.fill_BC("y-velocity")
def evolve(self):
"""
Evolve the incompressible equations through one timestep.
"""
u = self.cc_data.get_var("x-velocity")
v = self.cc_data.get_var("y-velocity")
gradp_x = self.cc_data.get_var("gradp_x")
gradp_y = self.cc_data.get_var("gradp_y")
phi = self.cc_data.get_var("phi")
myg = self.cc_data.grid
#---------------------------------------------------------------------
# create the limited slopes of u and v (in both directions)
#---------------------------------------------------------------------
limiter = self.rp.get_param("incompressible.limiter")
ldelta_ux = reconstruction.limit(u, myg, 1, limiter)
ldelta_vx = reconstruction.limit(v, myg, 1, limiter)
ldelta_uy = reconstruction.limit(u, myg, 2, limiter)
ldelta_vy = reconstruction.limit(v, myg, 2, limiter)
#---------------------------------------------------------------------
# get the advective velocities
#---------------------------------------------------------------------
"""
the advective velocities are the normal velocity through each cell
interface, and are defined on the cell edges, in a MAC type
staggered form
n+1/2
v
i,j+1/2
+------+------+
| |
n+1/2 | | n+1/2
u + U + u
i-1/2,j | i,j | i+1/2,j
| |
+------+------+
n+1/2
v
i,j-1/2
"""
# this returns u on x-interfaces and v on y-interfaces. These
# constitute the MAC grid
if self.verbose > 0:
print(" making MAC velocities")
_um, _vm = incomp_interface_f.mac_vels(myg.qx, myg.qy, myg.ng, myg.dx,
myg.dy, self.dt, u, v,
ldelta_ux, ldelta_vx, ldelta_uy,
ldelta_vy, gradp_x, gradp_y)
u_MAC = ai.ArrayIndexer(d=_um, grid=myg)
v_MAC = ai.ArrayIndexer(d=_vm, grid=myg)
#---------------------------------------------------------------------
# do a MAC projection ot make the advective velocities divergence
# free
#---------------------------------------------------------------------
# we will solve L phi = D U^MAC, where phi is cell centered, and
# U^MAC is the MAC-type staggered grid of the advective
# velocities.
if self.verbose > 0:
print(" MAC projection")
# create the multigrid object
mg = MG.CellCenterMG2d(myg.nx,
myg.ny,
xl_BC_type="periodic",
xr_BC_type="periodic",
yl_BC_type="periodic",
yr_BC_type="periodic",
xmin=myg.xmin,
xmax=myg.xmax,
ymin=myg.ymin,
ymax=myg.ymax,
verbose=0)
# first compute divU
divU = mg.soln_grid.scratch_array()
# MAC velocities are edge-centered. divU is cell-centered.
divU.v()[:, :] = \
(u_MAC.ip(1) - u_MAC.v())/myg.dx + (v_MAC.jp(1) - v_MAC.v())/myg.dy
# solve the Poisson problem
mg.init_zeros()
mg.init_RHS(divU)
mg.solve(rtol=1.e-12)
# update the normal velocities with the pressure gradient -- these
# constitute our advective velocities
phi_MAC = self.cc_data.get_var("phi-MAC")
solution = mg.get_solution()
phi_MAC.v(buf=1)[:, :] = solution.v(buf=1)
# we need the MAC velocities on all edges of the computational domain
b = (0, 1, 0, 0)
u_MAC.v(
buf=b)[:, :] -= (phi_MAC.v(buf=b) - phi_MAC.ip(-1, buf=b)) / myg.dx
b = (0, 0, 0, 1)
v_MAC.v(
buf=b)[:, :] -= (phi_MAC.v(buf=b) - phi_MAC.jp(-1, buf=b)) / myg.dy
#---------------------------------------------------------------------
# recompute the interface states, using the advective velocity
# from above
#---------------------------------------------------------------------
if self.verbose > 0:
print(" making u, v edge states")
_ux, _vx, _uy, _vy = \
incomp_interface_f.states(myg.qx, myg.qy, myg.ng,
myg.dx, myg.dy, self.dt,
u, v,
ldelta_ux, ldelta_vx,
ldelta_uy, ldelta_vy,
gradp_x, gradp_y,
u_MAC, v_MAC)
u_xint = ai.ArrayIndexer(d=_ux, grid=myg)
v_xint = ai.ArrayIndexer(d=_vx, grid=myg)
u_yint = ai.ArrayIndexer(d=_uy, grid=myg)
v_yint = ai.ArrayIndexer(d=_vy, grid=myg)
#---------------------------------------------------------------------
# update U to get the provisional velocity field
#---------------------------------------------------------------------
if self.verbose > 0:
print(" doing provisional update of u, v")
# compute (U.grad)U
# we want u_MAC U_x + v_MAC U_y
advect_x = myg.scratch_array()
advect_y = myg.scratch_array()
# u u_x + v u_y
advect_x.v()[:, :] = \
0.5*(u_MAC.v() + u_MAC.ip(1))*(u_xint.ip(1) - u_xint.v())/myg.dx + \
0.5*(v_MAC.v() + v_MAC.jp(1))*(u_yint.jp(1) - u_yint.v())/myg.dy
# u v_x + v v_y
advect_y.v()[:, :] = \
0.5*(u_MAC.v() + u_MAC.ip(1))*(v_xint.ip(1) - v_xint.v())/myg.dx + \
0.5*(v_MAC.v() + v_MAC.jp(1))*(v_yint.jp(1) - v_yint.v())/myg.dy
proj_type = self.rp.get_param("incompressible.proj_type")
if proj_type == 1:
u[:, :] -= (self.dt * advect_x[:, :] + self.dt * gradp_x[:, :])
v[:, :] -= (self.dt * advect_y[:, :] + self.dt * gradp_y[:, :])
elif proj_type == 2:
u[:, :] -= self.dt * advect_x[:, :]
v[:, :] -= self.dt * advect_y[:, :]
self.cc_data.fill_BC("x-velocity")
self.cc_data.fill_BC("y-velocity")
#---------------------------------------------------------------------
# project the final velocity
#---------------------------------------------------------------------
# now we solve L phi = D (U* /dt)
if self.verbose > 0:
print(" final projection")
# create the multigrid object
mg = MG.CellCenterMG2d(myg.nx,
myg.ny,
xl_BC_type="periodic",
xr_BC_type="periodic",
yl_BC_type="periodic",
yr_BC_type="periodic",
xmin=myg.xmin,
xmax=myg.xmax,
ymin=myg.ymin,
ymax=myg.ymax,
verbose=0)
# first compute divU
# u/v are cell-centered, divU is cell-centered
divU.v()[:, :] = \
0.5*(u.ip(1) - u.ip(-1))/myg.dx + 0.5*(v.jp(1) - v.jp(-1))/myg.dy
mg.init_RHS(divU / self.dt)
# use the old phi as our initial guess
phiGuess = mg.soln_grid.scratch_array()
phiGuess.v(buf=1)[:, :] = phi.v(buf=1)
mg.init_solution(phiGuess)
# solve
mg.solve(rtol=1.e-12)
# store the solution
phi[:, :] = mg.get_solution(grid=myg)
# compute the cell-centered gradient of p and update the velocities
# this differs depending on what we projected.
gradphi_x, gradphi_y = mg.get_solution_gradient(grid=myg)
# u = u - grad_x phi dt
u[:, :] -= self.dt * gradphi_x
v[:, :] -= self.dt * gradphi_y
# store gradp for the next step
if proj_type == 1:
gradp_x[:, :] += gradphi_x[:, :]
gradp_y[:, :] += gradphi_y[:, :]
elif proj_type == 2:
gradp_x[:, :] = gradphi_x[:, :]
gradp_y[:, :] = gradphi_y[:, :]
self.cc_data.fill_BC("x-velocity")
self.cc_data.fill_BC("y-velocity")
if self.particles is not None:
self.particles.update_particles(self.dt)
# increment the time
if not self.in_preevolve:
self.cc_data.t += self.dt
self.n += 1
def evolve(self):
"""
Evolve the incompressible equations through one timestep.
"""
u = self.cc_data.get_var("x-velocity")
v = self.cc_data.get_var("y-velocity")
gradp_x = self.cc_data.get_var("gradp_x")
gradp_y = self.cc_data.get_var("gradp_y")
phi = self.cc_data.get_var("phi")
myg = self.cc_data.grid
#---------------------------------------------------------------------
# create the limited slopes of u and v (in both directions)
#---------------------------------------------------------------------
limiter = self.rp.get_param("incompressible.limiter")
if (limiter == 0): limitFunc = reconstruction_f.nolimit
elif (limiter == 1): limitFunc = reconstruction_f.limit2
else: limitFunc = reconstruction_f.limit4
ldelta_ux = limitFunc(1, u.d, myg.qx, myg.qy, myg.ng)
ldelta_vx = limitFunc(1, v.d, myg.qx, myg.qy, myg.ng)
ldelta_uy = limitFunc(2, u.d, myg.qx, myg.qy, myg.ng)
ldelta_vy = limitFunc(2, v.d, myg.qx, myg.qy, myg.ng)
#---------------------------------------------------------------------
# get the advective velocities
#---------------------------------------------------------------------
"""
the advective velocities are the normal velocity through each cell
interface, and are defined on the cell edges, in a MAC type
staggered form
n+1/2
v
i,j+1/2
+------+------+
| |
n+1/2 | | n+1/2
u + U + u
i-1/2,j | i,j | i+1/2,j
| |
+------+------+
n+1/2
v
i,j-1/2
"""
# this returns u on x-interfaces and v on y-interfaces. These
# constitute the MAC grid
if self.verbose > 0: print(" making MAC velocities")
_um, _vm = incomp_interface_f.mac_vels(myg.qx, myg.qy, myg.ng,
myg.dx, myg.dy, self.dt,
u.d, v.d,
ldelta_ux, ldelta_vx,
ldelta_uy, ldelta_vy,
gradp_x.d, gradp_y.d)
u_MAC = patch.ArrayIndexer(d=_um, grid=myg)
v_MAC = patch.ArrayIndexer(d=_vm, grid=myg)
#---------------------------------------------------------------------
# do a MAC projection ot make the advective velocities divergence
# free
#---------------------------------------------------------------------
# we will solve L phi = D U^MAC, where phi is cell centered, and
# U^MAC is the MAC-type staggered grid of the advective
# velocities.
if self.verbose > 0: print(" MAC projection")
# create the multigrid object
mg = MG.CellCenterMG2d(myg.nx, myg.ny,
xl_BC_type="periodic",
xr_BC_type="periodic",
yl_BC_type="periodic",
yr_BC_type="periodic",
xmin=myg.xmin, xmax=myg.xmax,
ymin=myg.ymin, ymax=myg.ymax,
verbose=0)
# first compute divU
divU = mg.soln_grid.scratch_array()
# MAC velocities are edge-centered. divU is cell-centered.
divU.v()[:,:] = \
(u_MAC.ip(1) - u_MAC.v())/myg.dx + (v_MAC.jp(1) - v_MAC.v())/myg.dy
# solve the Poisson problem
mg.init_zeros()
mg.init_RHS(divU.d)
mg.solve(rtol=1.e-12)
# update the normal velocities with the pressure gradient -- these
# constitute our advective velocities
phi_MAC = self.cc_data.get_var("phi-MAC")
solution = mg.get_solution()
phi_MAC.v(buf=1)[:,:] = solution.v(buf=1)
# we need the MAC velocities on all edges of the computational domain
b = (0, 1, 0, 0)
u_MAC.v(buf=b)[:,:] -= (phi_MAC.v(buf=b) - phi_MAC.ip(-1, buf=b))/myg.dx
b = (0, 0, 0, 1)
v_MAC.v(buf=b)[:,:] -= (phi_MAC.v(buf=b) - phi_MAC.jp(-1, buf=b))/myg.dy
#---------------------------------------------------------------------
# recompute the interface states, using the advective velocity
# from above
#---------------------------------------------------------------------
if self.verbose > 0: print(" making u, v edge states")
_ux, _vx, _uy, _vy = \
incomp_interface_f.states(myg.qx, myg.qy, myg.ng,
myg.dx, myg.dy, self.dt,
u.d, v.d,
ldelta_ux, ldelta_vx,
ldelta_uy, ldelta_vy,
gradp_x.d, gradp_y.d,
u_MAC.d, v_MAC.d)
u_xint = patch.ArrayIndexer(d=_ux, grid=myg)
v_xint = patch.ArrayIndexer(d=_vx, grid=myg)
u_yint = patch.ArrayIndexer(d=_uy, grid=myg)
v_yint = patch.ArrayIndexer(d=_vy, grid=myg)
#---------------------------------------------------------------------
# update U to get the provisional velocity field
#---------------------------------------------------------------------
if self.verbose > 0: print(" doing provisional update of u, v")
# compute (U.grad)U
# we want u_MAC U_x + v_MAC U_y
advect_x = myg.scratch_array()
advect_y = myg.scratch_array()
# u u_x + v u_y
advect_x.v()[:,:] = \
0.5*(u_MAC.v() + u_MAC.ip(1))*(u_xint.ip(1) - u_xint.v())/myg.dx + \
0.5*(v_MAC.v() + v_MAC.jp(1))*(u_yint.jp(1) - u_yint.v())/myg.dy
# u v_x + v v_y
advect_y.v()[:,:] = \
0.5*(u_MAC.v() + u_MAC.ip(1))*(v_xint.ip(1) - v_xint.v())/myg.dx + \
0.5*(v_MAC.v() + v_MAC.jp(1))*(v_yint.jp(1) - v_yint.v())/myg.dy
proj_type = self.rp.get_param("incompressible.proj_type")
if proj_type == 1:
u.d[:,:] -= (self.dt*advect_x.d[:,:] + self.dt*gradp_x.d[:,:])
v.d[:,:] -= (self.dt*advect_y.d[:,:] + self.dt*gradp_y.d[:,:])
elif proj_type == 2:
u.d[:,:] -= self.dt*advect_x.d[:,:]
v.d[:,:] -= self.dt*advect_y.d[:,:]
self.cc_data.fill_BC("x-velocity")
self.cc_data.fill_BC("y-velocity")
#---------------------------------------------------------------------
# project the final velocity
#---------------------------------------------------------------------
# now we solve L phi = D (U* /dt)
if self.verbose > 0: print(" final projection")
# create the multigrid object
mg = MG.CellCenterMG2d(myg.nx, myg.ny,
xl_BC_type="periodic",
xr_BC_type="periodic",
yl_BC_type="periodic",
yr_BC_type="periodic",
xmin=myg.xmin, xmax=myg.xmax,
ymin=myg.ymin, ymax=myg.ymax,
verbose=0)
# first compute divU
# u/v are cell-centered, divU is cell-centered
divU.v()[:,:] = \
0.5*(u.ip(1) - u.ip(-1))/myg.dx + 0.5*(v.jp(1) - v.jp(-1))/myg.dy
mg.init_RHS(divU.d/self.dt)
# use the old phi as our initial guess
phiGuess = mg.soln_grid.scratch_array()
phiGuess.v(buf=1)[:,:] = phi.v(buf=1)
mg.init_solution(phiGuess.d)
# solve
mg.solve(rtol=1.e-12)
# store the solution
phi.d[:,:] = mg.get_solution(grid=myg).d
# compute the cell-centered gradient of p and update the velocities
# this differs depending on what we projected.
gradphi_x, gradphi_y = mg.get_solution_gradient(grid=myg)
# u = u - grad_x phi dt
u.d[:,:] -= self.dt*gradphi_x.d
v.d[:,:] -= self.dt*gradphi_y.d
# store gradp for the next step
if proj_type == 1:
gradp_x.d[:,:] += gradphi_x.d[:,:]
gradp_y.d[:,:] += gradphi_y.d[:,:]
elif proj_type == 2:
gradp_x.d[:,:] = gradphi_x.d[:,:]
gradp_y.d[:,:] = gradphi_y.d[:,:]
self.cc_data.fill_BC("x-velocity")
self.cc_data.fill_BC("y-velocity")
# increment the time
if not self.in_preevolve:
self.cc_data.t += self.dt
self.n += 1