MPHYS API
MPHYS (Multi-PHYSics) is a framework designed to perform multi-physics analysis and optimization, and is built on top of openMDAO. The API allows to interface DART with other software through MPHYS, and is implemented under api/mphys.
0. Importing the modules
Since MPHYS couples multiple software, it is required to install them before using MPHYS. As such, DART cannot be used from a development environement (it must be installed), and must be imported by calling,
from dartflo.dart.api.mphys import DartBuilderAdditionaly, the interface must be setup in an MPHYS class,
from mphys import Multipoint
class Top(Multipoint):
...1. Defining the parameters
The list of parameters required to setup the interface is essentialy a simplified version of that used for the internal API. Parameters are listed hereunder:
p = {
# Options
'Threads' : int, # number of threads
'Verb' : int, # verbosity
# Model (geometry or mesh)
'File' : str, # Input file containing the model
'Pars' : dict, # parameters for input file model
'Dim' : int, # problem dimension (2 or 3)
'Format' : str, # save format (vtk or gmsh)
# Markers...
'Fluid' : str, # name of physical group containing the fluid
'Farfield' : list of str, # LIST of names of physical groups containing the farfield boundaries (downstream should be last element)
# ... only 2D
'Wing' : str, # name of physical group containing the airfoil boundary
'Wake' : str, # name of physical group containing the wake
'Te' : str, # name of physical group containing the trailing edge
# ... only 3D
'Wings' : list of str, # LIST of names of physical groups containing the lifting surface boundary
'Wakes' : list of str, # LIST of names of physical group containing the wake
'WakeTips' : list of str, # LIST of names of physical group containing the edge of the wake (not for 2.5D)
'TeTips' : list of str, # LIST of names of physical group containing the edge of the wake and the trailing edge
# ... optional for 3D
'Symmetry' : str, # name of physical group containing the symmetry boundaries
# Freestream
'M_inf' : float, # freestream Mach number
'AoA' : float, # freestream angle of attack [deg] (optional, default=0)
'AoS' : float, # freestream angle of sideslip [deg] (optional, default=0)
'Q_inf' : float, # freesteam dynamic pressure (only required for aerostructural computations)
# Geometry
'S_ref' : float, # reference surface length
'c_ref' : float, # reference chord length
'x_ref' : float, # x-coordinate of reference point for moment computation
'y_ref' : float, # y-coordinate of reference point for moment computation
'z_ref' : float, # z-coordinate of reference point for moment computation
# Numerical
'LSolver' : 'GMRES', # inner solver (PARDISO, MUMPS or GMRES)
'G_fill' : int, # fill-in factor for GMRES preconditioner (optional, default=2)
'G_tol' : float, # tolerance for GMRES (optional, default=1e-5)
'G_restart' : int, # restart for GMRES (optional, default=50)
'Rel_tol' : float, # relative tolerance on solver residual
'Abs_tol' : float, # absolute tolerance on solver residual
'Max_it' : int # maximum number of iterations for nonlinear solver
}Note DART can be coupled with pyGeo, which uses the free-form deformation technique, to perform aerodynamic shape optimization. Since pyGeo only handles 3D geometries, users wanting to perform 2D shape optimization must provide a so-called 2.5D geometry, which consists of an extruded 2D geometry enclosed between two symmetry walls. In such a case, the parameters 'WakeTips' MUST NOT be given.
2. Using the interface
Once the parameters have been defined, the interface can simply be setup by calling,
dart = DartBuilder(p, scenario=..., task=...)where valid choices for scenario are 'aerodynamic' or 'aerostructural', and valid choices for task are 'analysis' or 'optimization'.
Users must then refer to the MPHYS documention to connect the interface through MPHYS. In version 0.4.0, this is done by calling,
# for pure aerodynamic computations...
from mphys.scenario_aerodynamic import ScenarioAerodynamic
self.mphys_add_scenario('...', ScenarioAerodynamic(aero_builder=dart))
# ... or for aerostructural computations
from mphys.scenario_aerostructural import ScenarioAeroStructural
self.mphys_add_scenario('...', ScenarioAeroStructural(aero_builder=dart, struct_builder=..., ldxfer_builder=...), coupling_nonlinear_solver=..., coupling_linear_solver=...)