def draglift(simulations, sortby="dx", **kwargs):
"""
Compute mean drag coefficient, rms lift coefficient, and Strouhal number
for flow past a circular cylinder.
If the flow is steady, only drag and lift coefficients are computed.
Call signature:
draglift(simulations, d_cylinder=0.1, u_0=1.0, flow_dir='y',
t_start=-1, sortby='dx'):
Keyword arguments:
*simulations*
array of simulation names to be included in the computations
*d_cylinder*:
diameter of the cylinder
*u_0*
velocity at the inlet
*flow_dir*:
direction of the flow
*t_start*
time to start the drag computations from
should be where the a steady vortex shedding has developed
*sortby*
property to sort the arrays by
typical choices for parametric studies are grid size, length of domain, etc.
Returns
object with information: sim-name, drag (mean), lift (rms), and st (non-dim shedding frequency)
"""
sims = []
for simulation in simulations:
sims.append(sim.get(simulation, quiet=True))
# Sort simulations
sims = sim.sort(sims, sortby, reverse=True)
draglift_tmp = []
for i, thissim in enumerate(sims):
draglift_tmp.append(Draglift())
draglift_tmp[i].set_name(thissim)
draglift_tmp[i].compute(thissim, **kwargs)
return draglift_tmp
def twonorm_accuracy1D(simulations,
field='ur',
strip=1,
direction='r',
varfile='ogvar.dat',
noerr=True,
quiet=True):
"""
Assessment of accuracy of simulation:
Computes the two-norm error of all available simulation, where the simulation
with the maximum amount of grid points is used as the correct/reference solution.
E.g., for runs with grid points assessment of accuracy of x-component of velocity
along the y-direction, for runs with grid points nxgrid = n, 2n, 4n, 8n, compute
|| u_n - u_0 || = dy \sum\limits_{n=0}^n (sqrt(u_n(x_n)-u_0(x_8n)))
for all runs (except for the 8n case, used as reference).
Requires that the runs have matching grids, that is, grid refined by a factor of 2m,
and grids adjusted so that the grid point overlap (needs ofset if periodic BC is used).
call signature:
twonorm_accuracy(simulations)
Keyword arguments:
*simulations*
array of simulation names to be included in the computations
*field*
variable used in accuracy assessment
*varfile*:
name of varfile to read from each sim
*noerr*:
set to false if you want to return an array of maximum error along strip, in
addition to the two-norm
Returns
array of two-norms where the larges array is used as base
"""
import numpy as np
import os as os
from pencil import read
from pencil import sim
# Find directories to include in accuracy assessment
sims = []
for simulation in simulations:
sims.append(sim.get(simulation, quiet=True))
# Sort runs by size of grid spacing
sims = sim.sort(sims, 'dx', reverse=True)
# From this point we only need the varfile to compute accuracy
# Need to update dim to ogdim for reading of ogvar to be done
# correctly from simulation object
for i, thissim in enumerate(sims):
sims[i].dim = read.ogdim(datadir=thissim.datadir)
sims[i] = read.ogvar(sim=thissim, trimall=True, varfile=varfile)
# Check that increase in size is correct for use in two-norm calculation
nsims = len(sims)
nx_min = sims[0].r.size
ny_min = sims[0].th.size
for thissim in sims:
if ((thissim.r.size - 1) % (nx_min - 1) != 0):
print('ERROR: Incorrect size in r-dir')
print('sims.r', thissim.r.size)
print('nx_min', nx_min)
return False
if (thissim.th.size % ny_min != 0):
print('ERROR: Incorrect size in th-dir')
return False
# Check that all var-files are for the same time
t = sims[0].t
for thissim in sims:
if thissim.t != t:
print('WARNING: Incorrect time for one or more simulations')
# Now we are sure that first coordinate of r and th are the same for all runs
# Can compute the two-norms for increasing sizes. Use largest size as normalization of error
twonorms = np.zeros(nsims - 1)
maxerrs = np.zeros(nsims - 1)
# Compute array of factor used to jump indices when comparing two arrays of size N and 2N etc.
# Usually n2_fac = [8, 4, 2] or similar
n2_fac = np.empty(nsims - 1)
for i, thissim in enumerate(sims[:-1]):
n2_fac[i] = thissim.dx / sims[-1].dx
u2 = getattr(sims[-1], field)
if not (field == 'ux' or field == 'uy'):
u2 = u2[0, :, :]
for i, thissim in enumerate(sims[:-1]):
u1 = getattr(thissim, field)
if not (field == 'ux' or field == 'uy'):
u1 = u1[0, :, :]
dr = np.empty(thissim.r.size)
dr[0:-1] = thissim.r[1:] - thissim.r[0:-1]
dr[-1] = dr[-2]
dth = thissim.dy
twonorms[i] = 0.
n2 = n2_fac[i]
if (direction == 'r'):
r = sims[0].r[strip]
j = int(strip * sims[0].dx / thissim.dx)
for k in range(thissim.th.size):
twonorms[i] = twonorms[i] + dth * r * (
u1[k, j] - u2[int(k * n2), int(j * n2)])**2
elif (direction == 'th'):
k = int(strip * sims[0].dx / thissim.dx)
for j in range(thissim.r.size):
twonorms[i] = twonorms[i] + dr[j] * (
u1[k, j] - u2[int(k * n2), int(j * n2)])**2
else:
print('ERROR: Invalid direction chosen')
return False
twonorms[i] = np.sqrt(twonorms[i])
if not noerr:
return twonorms, maxerrs
else:
return twonorms
def twonorm_accuracy(simulations,
field='ux',
strip=0,
var_file='ogvar.dat',
direction='x',
noerr=True,
quiet=True):
"""
Assessment of accuracy of simulation:
Computes the two-norm error of all available simulation, where the simulation
with the maximum amount of grid points is used as the correct/reference solution.
E.g., for runs with grid points assessment of accuracy of x-component of velocity
along the y-direction, for runs with grid points nxgrid = n, 2n, 4n, 8n, compute
|| u_n - u_0 || = dy \sum\limits_{n=0}^n (sqrt(u_n(x_n)-u_0(x_8n)))
for all runs (except for the 8n case, used as reference).
Requires that the runs have matching grids, that is, grid refined by a factor of 2m,
and grids adjusted so that the grid point overlap (needs ofset if periodic BC is used).
call signature:
twonorm_accuracy(simulations)
Keyword arguments:
*simulations*
array of simulation names to be included in the computations
*field*
variable used in accuracy assessment
*strip*:
index for strip along coordinate
*var_file*:
name of varfile to read from each sim
*direction*:
compute two-norm along 'x' or 'y' direction
*noerr*:
set to false if you want to return an array of maximum error along strip, in
addition to the two-norm
Returns
array of two-norms where the larges array is used as base
"""
import numpy as np
import os as os
from pencil import read
from pencil import sim
# Find directories to include in accuracy assessment
sims = []
for simulation in simulations:
sims.append(sim.get(simulation, quiet=True))
# Sort runs by size of grid spacing
if (direction == 'x' or direction == 'r'):
sims = sim.sort(sims, 'nx', reverse=False)
elif (direction == 'y' or direction == 'th'):
sims = sim.sort(sims, 'ny', reverse=False)
# From this point we only need the varfile to compute accuracy
# Need to update dim to ogdim for reading of ogvar to be done
# correctly from simulation object
for i, thissim in enumerate(sims):
sims[i].dim = read.ogdim(datadir=thissim.datadir)
sims[i] = read.ogvar(sim=thissim, trimall=True, var_file=var_file)
# Check that increase in size is correct for use in two-norm calculation
nsims = len(sims)
nx_min = sims[0].r.size
ny_min = sims[0].th.size
for thissim in sims:
if ((thissim.r.size - 1) % (nx_min - 1) != 0):
print('ERROR: Incorrect size in r-dir')
print('sims.r', thissim.r.size)
print('nx_min', nx_min)
return False
if (thissim.th.size % ny_min != 0):
print('ERROR: Incorrect size in th-dir')
return False
# Check that all var-files are for the same time
t = sims[0].t
for thissim in sims:
if thissim.t != t:
print('WARNING: Incorrect time for one or more simulations')
# Now we are sure that first coordinate of r and th are the same for all runs
# Can compute the two-norms for increasing sizes. Use largest size as normalization of error
twonorms = np.zeros(nsims - 1)
maxerrs = np.zeros(nsims - 1)
if (direction == 'x' or direction == 'r'):
dh = sims[0].dx
n2_factor = int(dh / sims[-1].dx)
elif (direction == 'y' or direction == 'th'):
dh = sims[0].dy
n2_factor = int(dh / sims[-1].dy)
attribute = getattr(sims[-1], field)
if (field == 'ux' or field == 'uy'):
u2 = attribute[0::n2_factor, 0::n2_factor]
else:
u2 = attribute[0, 0::n2_factor, 0::n2_factor]
strip = int(strip)
if (direction == 'x' or direction == 'r'):
dh = sims[-1].dx
dx_max = sims[0].dx
n2_factor = int(thissim.dx / dh)
#for i,thissim in enumerate(sims[:-1]):
# strips[i]=int(thissim.dx/dx_max*strip)
#n1_factor = int(sims[0].dx/sims[-1].dx)
elif (direction == 'y' or direction == 'th'):
dh = sims[-1].dy
dx_max = sims[0].dy
#for i,thissim in enumerate(sims[:-1]):
# strips[i]=int(thissim.dy/dx_max*strip)
#n1_factor = int(sims[0].dx/sims[-1].dy)
attribute = getattr(sims[-1], field)
# if(field=='ux' or field=='uy'):
# u2 = attribute[0::n2_factor,0::n2_factor]
# else:
# u2 = attribute[0,0::n2_factor,0::n2_factor]
j = 1
for i, thissim in enumerate(sims[:-1]):
n1_factor = 1
if (direction == 'x' or direction == 'r'):
n2_factor = int(thissim.dx / dh)
elif (direction == 'y' or direction == 'th'):
n2_factor = int(thissim.dy / dh)
u1 = getattr(thissim, field)
if (field == 'ux' or field == 'uy'):
u2 = attribute[0::n2_factor, 0::n2_factor]
#u1 = u1[0::n1_factor]
else:
u2 = attribute[0, 0::n2_factor, 0::n2_factor]
u1 = u1[0, :, :] #0::n1_factor,:]
#u1 = u1[0,0::n1_factor,:]
radius_l = sims[-1].r[0::n2_factor]
if (direction == 'x' or direction == 'r'):
twonorms[i] = (twonorm(u1[:, strip * j], u2[:, strip * j],
thissim.dy * sims[0].r[strip]))
maxerrs[i] = (maxerror(u1[:, strip * j], u2[:, strip * j]))
elif (direction == 'y' or direction == 'th'):
twonorms[i] = (twonorm(u1[strip * j, :], u2[strip * j, :],
thissim.dx))
maxerrs[i] = (maxerror(u1[strip * j, :], u2[strip * j, :]))
j = j * 2
# n1_factor = 1
# u1 = getattr(thissim,field)
# if(not(field=='ux' or field=='uy')):
# u1=u1[0,:,:]
#
# if(direction=='x' or direction=='r'):
# n1_factor = int(dx_max/thissim.dx)
# n2_factor = int(thissim.dx/dh)
# u1 = u1[:,0::n1_factor]
# u2 = attribute[0,0::n2_factor,0::n2_factor]
# u2 = u2[:,0::n1_factor]
# elif(direction=='y' or direction=='th'):
# n1_factor = int(dx_max/thissim.dy)
# n2_factor = int(thissim.dy/dh)
# u1 = u1[0::n1_factor,:]
# u2 = attribute[0,0::n2_factor,0::n2_factor]
# u2 = u2[0::n1_factor,:]
#
# if(direction=='x' or direction=='r'):
# twonorms[i] = (twonorm(u1[:,strip],u2[:,strip],thissim.dy*sims[0].r[strip]))
# maxerrs[i] = (maxerror(u1[:,strip],u2[:,strip]))
# elif(direction=='y' or direction=='th'):
# twonorms[i] = (twonorm(u1[strip,:],u2[strip,:],thissim.dx))
# maxerrs[i] = (maxerror(u1[strip,:],u2[strip,:]))
if (not quiet):
print('Two-norm computed for field:', field, ', along strip:', strip)
if (direction == 'x'):
print('Along x-direction')
elif (direction == 'r'):
print('Along r-direction')
elif (direction == 'y'):
print('Along y-direction')
elif (direction == 'th'):
print('Along th-direction')
if not noerr:
return twonorms, maxerrs
else:
return twonorms