In contrast to the other Toro examples, this setup uses a higher-order discretization and the positivity preserving filter to simulate the evaluation of the Riemann problem with a strong discontinuity. An oversampling by a factor of 3 is used and in the projection we use Chebyshev-Lobatto points in the nodal representation.
The complete configuration is provided in ateles.lua
:
-- Toro4 setup solving a Riemann problem in the Euler 2D equations.
-- This setup uses a higher order and the positivity preserving filter and
-- oversampling to compute a strong shock.
-- For the timeintegration the two-stage, strong stability preserving
-- Runge-Kutta scheme is used.
--
-- The initial conditions for the Riemann problem
-- ... left state
rho_l = 1.0
u_l = 0.0
p_l = 0.1
-- ... right state
rho_r = 1.0
u_r = 0.0
p_r = 5.0
-- global simulation options
simulation_name = 'toro4_euler_modg_2d'
sim_control = {
time_control = {
min = 0,
max = 0.012,
interval = {iter = 1}
}
}
check = {interval = 1}
-- Mesh definitions --
channel_length = 1.0
epsx = channel_length*1.0e-6
mesh = {
predefined = 'line_bounded',
origin = {0, 0, 0},
length = channel_length,
element_count = 40
}
-- Equation definitions --
equation = {
name = 'euler_2d',
isen_coef = 1.4,
r = 296.0,
numflux = 'godunov',
material = {
characteristic = 0,
relax_velocity = {0, 0},
relax_temperature = 0
}
}
-- (cv) heat capacity and (r) ideal gas constant
equation["cv"] = equation["r"] / (equation["isen_coef"] - 1.0)
function rho(x,y,z)
if ( x < channel_length/2.0 ) then
return rho_l
else
return rho_r
end
end
function p(x,y,z)
if ( x < channel_length/2.0 ) then
return p_l
else
return p_r
end
end
function u(x,y,z)
if ( x < channel_length/2.0 ) then
return u_l
else
return u_r
end
end
-- Scheme definitions --
scheme = {
-- the spatial discretization scheme
spatial = {
name = 'modg_2d',
m = 3
},
-- the temporal discretization scheme
temporal = {
name = 'explicitSSPRungeKutta',
steps = 2,
control = {
name = 'cfl',
cfl = 0.6
}
},
stabilization = {
name = 'cons_positivity_preserv',
eps = 1.0e-6
}
}
projection = {
kind = 'l2p',
factor = 3.0,
nodes_kind = 'chebyshev',
lobattoPoints = true
}
initial_condition = {
density = rho,
pressure = p,
velocityX = u,
velocityY = 0
}
-- Boundary conditions
boundary_condition = {
{
label = 'west',
kind = 'inflow_normal',
density = rho_l,
v_norm = u_l,
v_tan = 0.0
},
{
label = 'east',
kind = 'outflow',
pressure = p_r
}
}
-- Tracking
tracking = {
label = 'probe_density_toro',
folder = '',
variable = {'density'},
shape = {
kind = 'canoND',
object= {
origin = {
(channel_length/2.0) + epsx,
epsx,
epsx
}
}
},
time_control = {
min = 0,
max = sim_control.time_control.max,
interval = sim_control.time_control.max/20.0
},
output = { format = 'ascii', ndofs = 1 }
}
Features used
Projection: l2p, chebyshev-lobatto
Polynomial representation: Q
Filtering: cons_positivity_preserv
Timestepping: explicitSSPRungeKutta, 2 steps
Boundary conditions: inflow_normal
, outflow