def set_ic_rayleigh_benard_benchmark(model):
noise = dedaLES.random_noise(model.domain)
# Linear background + perturbations damped at walls
zbottom, ztop = model.zbasis.interval
a = model.problem.parameters['a']
Bz = model.problem.parameters['B0']/(ztop-zbottom)
z = model.z
pert = a * noise * (z - ztop) * (z - zbottom)
model.set_fields(b=Bz*(z - pert))
""".format(surface_heat_flux, surface_buoyancy_flux, 1/initial_N, initial_dt, run_time,
Lx, Ly, Lz, nx, ny, nz,
turb_vel_scale, erosion_time_scale, kolmogorov_length_scale, Δx, Δy, Δz_min, Δz_max,
closure_name)
)
# Boundary conditions
model.set_bc("no penetration", "top", "bottom")
model.set_bc("free slip", "top", "bottom")
model.set_tracer_gradient_bc("b", "top", gradient="surface_bz") #*tanh(t/tb)")
model.set_tracer_gradient_bc("b", "bottom", gradient="initial_N2")
model.build_solver(timestepper='SBDF3')
# Initial condition
noise = noise_amplitude * dedaLES.random_noise(model.domain) * model.z * (Lz - model.z) / Lz**2
initial_b = initial_N2*model.z
model.set_fields(
u = noise,
v = noise,
b = initial_b + np.sqrt(initial_N2) * noise
#w = noise,
)
model.stop_at(sim_time=run_time)
dt_gizmo = dedaLES.TimeStepGizmo(model.solver, initial_dt=initial_dt, cadence=dt_cadence, max_change=1.5, safety=dt_safety)
dt_gizmo.add_velocities(('u', 'v', 'w'))
dt_gizmo.add_diffusivity('ν_sgs')
dt_gizmo.add_diffusivity('κb_sgs')
model.set_tracer_gradient_bc('v', "bottom", gradient="-Vgz")
model.set_tracer_gradient_bc("b", "top", gradient="bz_surf")
model.set_tracer_gradient_bc("b", "bottom", gradient='bz_deep')
model.build_solver(timestepper='CNAB2')
# Initial condition
def smoothstep(z, d):
return 0.5 * (1 + np.tanh(z / d))
b0 = bz_deep * (model.z + h0) * smoothstep(-model.z - h0, d)
# Add noise ... ?
noise = dedaLES.random_noise(model.domain)
b0 = b0 + b_noise * noise
model.set_fields(b=b0, u=0, v=0, w=0)
# CFL conditions
CFL = flow_tools.CFL(model.solver,
initial_dt=1e-2,
cadence=1,
max_change=1.5,
max_dt=10,
safety=0.5)
CFL.add_velocities(('u', 'v+Vg', 'w'))
#Analysis tasks
snap = model.solver.evaluator.add_file_handler('snapshots', sim_dt=30)
#snap.add_task("interp(b, z=0)", scales=1, name='b surface')
ny=64,
nz=32,
ν=ν,
κ=κ,
Δb=1,
closure=closure)
model.set_bc("no penetration", "top", "bottom")
model.set_bc("no slip", "top", "bottom")
model.problem.add_bc("right(b) = 0")
model.problem.add_bc("left(b) = Δb")
model.build_solver()
# Set initial condition: unstable buoyancy grad + random perturbations
noise = a * dedaLES.random_noise(
model.domain) * model.z * (model.Lz - model.z) / model.Lz**2,
model.set_fields(u=noise, v=noise, w=noise, b=model.z / model.Lz - noise)
model.stop_at(sim_time=100)
# Analysis
if closure is None: closure_name = 'DNS'
else: closure_name = closure.__class__.__name__
simulation_name = "rayleigh_benard_snapshots_{:s}".format(closure_name)
analysis = model.solver.evaluator.add_file_handler(simulation_name,
iter=100,
max_writes=100)
analysis.add_system(model.solver.state, layout='g')
stats = flow_tools.GlobalFlowProperty(model.solver, cadence=10)
stats.add_property("sqrt(u*u + v*v + w*w) / ν", name="Re")
model = dns.DNS_3P_Box(nx=nx,
ny=ny,
nz=nz,
Lx=Lx,
Ly=Ly,
Lz=Lz,
ν=1.0,
closure=closure)
# model = channel_mod.ChannelMod_DNS(nx=nx, ny=ny, nz=nz, Lx=Lx, Ly=Ly, Lz=Lz, xleft=nx, yleft=ny, zbottom=nz,
# nu=1.0, rho=1.0)
model.build_solver()
# Random initial condition. Re_k = u k / ν => u ~ ν * Re_k / k
Re = 1000.0 # Re at grid scale
u0 = Re / nx
model.u['g'] = u0 * dedaLES.random_noise(model.domain, seed=23)
model.v['g'] = u0 * dedaLES.random_noise(model.domain, seed=42)
model.u['g'] = model.u['g'] - np.mean(model.u['g'])
model.v['g'] = model.v['g'] - np.mean(model.v['g'])
# Diagnose w from continuity
ux = model.domain.new_field()
vy = model.domain.new_field()
wz = model.domain.new_field()
model.u.differentiate('x', out=ux)
model.v.differentiate('y', out=vy)
model.w.differentiate('z', out=wz)
wz['g'] = -ux['g'] - vy['g']
wz.integrate('z', out=model.w)
spinup_model = dedaLES.BoussinesqChannelFlow(Lx=Lx,
Ly=Ly,
Lz=Lz,
nx=nx_spinup,
ny=ny_spinup,
nz=nz_spinup,
ν=ν,
κ=κ,
Δb=Δb,
closure=closure,
Ra=Ra)
set_rayleigh_benard_bcs(spinup_model)
spinup_model.build_solver(timestepper='SBDF3')
# Set initial condition: unstable buoyancy grad + random perturbations
noise = a * dedaLES.random_noise(
spinup_model.domain) * spinup_model.z * (Lz - spinup_model.z) / Lz**2,
spinup_model.set_fields(u=noise,
v=noise,
w=noise,
b=spinup_model.z / Lz - noise)
spinup_model.stop_at(sim_time=spinup_time)
# Make CFL
spinup_CFL = flow_tools.CFL(spinup_model.solver,
initial_dt=dt0,
cadence=10,
max_change=1.5,
safety=0.5)
spinup_CFL.add_velocities(('u', 'v', 'w'))
# Flow properties: Reynolds number and three Nusselt numbers