run_vlm.py

""" Example runscript to perform aerodynamics-only optimization.

Call as `python run_vlm.py 0` to run a single analysis, or
call as `python run_vlm.py 1` to perform optimization.

To run with multiple lifting surfaces instead of a single one,
Call as `python run_vlm.py 0m` to run a single analysis, or
call as `python run_vlm.py 1m` to perform optimization.

"""

from __future__ import division, print_function
import sys
from time import time
import numpy as np

# Append the parent directory to the system path so we can call those Python
# files. If you have OpenAeroStruct in your PYTHONPATH, this is not necessary.
from os import sys, path
sys.path.append(path.dirname(path.dirname(path.abspath(__file__))))

from OpenAeroStruct import OASProblem

# Suppress warnings
import warnings
warnings.filterwarnings("ignore")

if __name__ == "__main__":

    # Make sure that the user-supplied input is one of the valid options
    input_options = ['0', '0m', '1', '1m']
    print_str = ''.join(str(e) + ', ' for e in input_options)

    # Parse the user-supplied command-line input and store it as input_arg
    try:
        input_arg = sys.argv[1]
        if input_arg not in input_options:
            raise(IndexError)
    except IndexError:
        print('\n +---------------------------------------------------------------+')
        print(' | ERROR: Please supply a correct input argument to this script. |')
        print(' | Possible options are ' + print_str[:-2] + '                             |')
        print(' | See the docstring at the top of this file for more info.      |')
        print(' +---------------------------------------------------------------+\n')
        raise

    # Set problem type
    prob_dict = {'type' : 'aero'}

    if sys.argv[1].startswith('0'):  # run analysis once
        prob_dict.update({'optimize' : False})
    else:  # perform optimization
        prob_dict.update({'optimize' : True})

    # Instantiate problem and add default surface
    OAS_prob = OASProblem(prob_dict)

    # Create a dictionary to store options about the surface
    surf_dict = {'num_y' : 7,
                 'num_x' : 2,
                 'wing_type' : 'rect',
                 'CD0' : 0.015,
                 'symmetry' : True,
                 'num_twist_cp' : 2,
                 'num_thickness_cp' : 2}

    # Add the specified wing surface to the problem
    OAS_prob.add_surface(surf_dict)

    # Single lifting surface
    if not sys.argv[1].endswith('m'):

        # Setup problem and add design variables, constraint, and objective
        OAS_prob.add_desvar('wing.twist_cp', lower=-10., upper=15.)
        OAS_prob.add_desvar('wing.sweep', lower=10., upper=30.)
        OAS_prob.add_desvar('wing.dihedral', lower=-10., upper=20.)
        OAS_prob.add_desvar('wing.taper', lower=.5, upper=2.)
        OAS_prob.add_constraint('wing_perf.CL', equals=0.5)
        OAS_prob.add_objective('wing_perf.CD', scaler=1e4)
        OAS_prob.setup()

    # Multiple lifting surfaces
    else:

        # Add additional lifting surface
        OAS_prob.add_surface({'name' : 'tail',
                              'span' : 3.,
                              'num_y' : 7,
                              'span_cos_spacing' : .5,
                              'offset' : np.array([5., 0., .1]),
                              'symmetry' : True})

        # Set up wing variables
        OAS_prob.add_desvar('wing.twist_cp', lower=-10., upper=15.)
        OAS_prob.add_desvar('wing.sweep', lower=10., upper=30.)
        OAS_prob.add_desvar('wing.dihedral', lower=-10., upper=20.)
        OAS_prob.add_desvar('wing.taper', lower=.5, upper=2.)
        OAS_prob.add_constraint('wing_perf.CL', equals=0.5)
        OAS_prob.add_objective('wing_perf.CD', scaler=1e4)

        # Set up tail variables
        OAS_prob.add_desvar('tail.twist_cp', lower=-10., upper=15.)
        OAS_prob.add_desvar('tail.sweep', lower=10., upper=30.)
        OAS_prob.add_desvar('tail.dihedral', lower=-10., upper=20.)
        OAS_prob.add_desvar('tail.taper', lower=.5, upper=2.)
        OAS_prob.add_constraint('tail_perf.CL', equals=0.5)

        # Setup problem
        OAS_prob.setup()

    st = time()

    # Actually run the problem
    OAS_prob.run()

    print("\nWing CL:", OAS_prob.prob['wing_perf.CL'])
    print("Wing CD:", OAS_prob.prob['wing_perf.CD'])
    print("Time elapsed: {} secs".format(time() - st))