global bx_scale, by_scale
bx_scale = 1.04
by_scale = 1.04
# origin
o = Node(0.0, 0.0)
# sphere surface nodes
a = Node(-Rn, 0.0)
b = Node(0.0, Rn)
# inflow boundary nodes
inflow_nodes = []
np = 16
y_top = by_scale * y_from_x(b.x / bx_scale, M_inf, theta=0.0, axi=1, R_nose=Rn)
dy = y_top / (np - 1)
for iy in range(np):
y = dy * iy
x = -bx_scale * x_from_y(y / by_scale, M_inf, theta=0.0, axi=1, R_nose=Rn)
inflow_nodes.append(Node(x, y))
print inflow_nodes[-1].str()
# curves
west = Spline(inflow_nodes)
south = Line(inflow_nodes[0], a)
north = Line(inflow_nodes[-1], b)
east = Arc(a, b, o)
# Define the blocks, boundary conditions and set the discretisation.
nnx = 60
nny = 60
nbx = 4
nby = 4
betaNS = 1.0 # clustering
# We have made sure that our query surface is within the bounds of the original.
q0 = Vector3(0.0, -L2, L2)
q1 = Vector3(0.0, -L2, 0.0)
q2 = Vector3(0.0, L2, 0.0)
q3 = Vector3(0.0, L2, L2)
qsurf2 = CoonsPatch(q0, q1, q2, q3, "query_surface")
east = MappedSurface(qsurf2, surf1)
# The outer mesh surface is derived from Billig's shock-shape correlation.
# In preparation for defining nodes, generate a few sample points
# along the expected shock position.
e = [] # will use a list to keep the nodes for the shock boundary
for y in [0.0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2]:
y *= Dmax/2.0 # scale up to cover the base of the vehicle
# Note that we lie about the cone angle. Detached shock.
x = x_from_y(y, M_inf, theta=20.0/180.0*pi, axi=1, R_nose=Rnose)
# print "x=", x, "y=", y
# the outer boundary should be a little further than the shock itself
e.append( Vector(-1.2*x, 1.2*y, 0.0) )
shock = Spline(e)
# print "shock=", shock
surf2 = RevolvedSurface(shock, "shock_surface")
L3 = e[-1].y / sqrt(2.0)
qs0 = Vector3(0.0, -L3, L3)
qs1 = Vector3(0.0, -L3, 0.0)
qs2 = Vector3(0.0, L3, 0.0)
qs3 = Vector3(0.0, L3, L3)
qsurf2 = CoonsPatch(qs0, qs1, qs2, qs3, "query_surface_shock")
west = MappedSurface(qsurf2, surf2)
p0 = west.eval(0.0, 0.0)
def zero_func(y):
# from cfpylib.gasdyn.billig import x_from_y
return -bx_scale * x_from_y(
y / by_scale, M_inf, theta=0.0, axi=1, R_nose=Rn) - y / tan(pi - theta)
u=0.0,
v=0.0,
T=[T_inf, T_inf],
massf=[
1.0,
])
# Build the geometry from the bottom-up, starting with nodes...
# Scale it with the cylinder radius.
# In preparation for defining nodes, generate a few sample points
# along the expected shock position
# (which is estimated via Billig's correlation).
xys = []
for y in [0.0, 0.5, 1.0, 1.5, 2.0, 2.5]:
x = x_from_y(y, M_inf, theta=0.0, axi=0, R_nose=Rc)
xys.append((x, y)) # a new coordinate pair
print "x=", x, "y=", y
a = Node(-Rc, 0.0, label="a")
b = Node(0.0, Rc, label="b")
c = Node(0.0, 0.0, label="c")
d = [] # will use a list to keep the nodes for the shock boundary
for x, y in xys:
# the outer boundary should be a little further than the shock itself
d.append(Node(-1.1 * x, 1.1 * y, label="d"))
# ...then lines, arcs, etc, that will make up the block boundaries.
axis = Line(d[0], a) # first-point of shock to nose of cylinder
cylinder = Arc(a, b, c)
shock = Spline(d)