Version 1.2

Version 1.2 - Transonic correction and analytical gradients

This version mainly features a transonic solver and analytical pressure derivatives.

Changes

• Add transonic correction
• Add analytical gradients
• Add feature to deform the body
• Fix calculation of motion-induced velocity and unsteady pressure
• Refactor APIs and utilities

Notes

Transonic correction
The unsteady pressure solution can now be corrected by higher-fidelity data (typically obtained from CFD) to include transonic and viscous effects.
Analytical gradients
Although CoDiPack works well, its memory footprint is too large for practical unsteady cases (see #6). Analytical pressure and aerodynamic forces gradients have therefore been implemented so that flutter constrained optimization can be performed within a reasonable computational time.
Body deformation
The body nodes can now be set to new positions for aeroelastic and optimization purposes.
Formulation fixes
The calculation of the surface velocity induced by a rigid pitching motion has been corrected to use original instead of compressible coordinates. Additionally, a mistake in the calculation of the unsteady pressure coefficient has been fixed.
Refactoring
The default values in the API have been refactored. The slicing utility now also outputs z-coordinates.

Tests

• Ubuntu 22.04 (gcc 11, python 3.10)

sdpm/api/core.py

@@ -17,15 +17,13 @@
 ## Initialize SDPM
 # Adrien Crovato
 
-def init_sdpm(cfg, use_ad=False):
+def init_sdpm(cfg):
     """Initialize SDPM components
 
     Parameters
     ----------
     cfg : dict
         Dictionary of parameters to configure SDPM
-    use_ad : bool, optional
-        Whether to use AD within SDPM (default: False)
 
     Returns
     -------
@@ -44,13 +42,13 @@ def init_sdpm(cfg, use_ad=False):
             Lifting body
         sol : sdpm.Solver object
             Direct solver
-        adj : sdpm.Adjoint object
-            Adjoint solver
+        grd : sdpm.Gradient object
+            Gradient calculator
     """
     # Imports
     import sdpm
     from sdpm.gmsh import MeshLoader
-    from sdpm.utils import interpolate_modes
+    from sdpm.utils import interpolate_modes, interpolate_pressure
     import math
 
     # Sanity checks
@@ -58,14 +56,14 @@ def init_sdpm(cfg, use_ad=False):
         raise RuntimeError('Symmetric (half) geometric model cannot be used with nonzero angle of sideslip (AoS)!\n')
 
     # Mesh
-    pars = {} if 'Pars' not in cfg else cfg['Pars']
+    pars = cfg.get('Pars', {})
     _msh = MeshLoader(cfg['File']).run(pars)
     _wrt = sdpm.GmshExport(_msh)
 
     # Problem
-    aoa = 0 if 'AoA' not in cfg else cfg['AoA'] * math.pi / 180
-    aos = 0 if 'AoS' not in cfg else cfg['AoS'] * math.pi / 180
-    minf = 0 if 'Mach' not in cfg else cfg['Mach']
+    aoa = cfg.get('AoA', 0.) * math.pi / 180
+    aos = cfg.get('AoS', 0.) * math.pi / 180
+    minf = cfg.get('Mach', 0.)
     _pbl = sdpm.Problem(_msh)
     _pbl.setGeometry(cfg['s_ref'], cfg['c_ref'], cfg['x_ref'], cfg['y_ref'], cfg['z_ref'], cfg['Symmetry'])
     _pbl.setFreestream(aoa, aos, minf)
@@ -79,12 +77,17 @@ def init_sdpm(cfg, use_ad=False):
         x_modes, amp_modes = interpolate_modes(cfg['Modes'], _bdy.getNodes())
         for i in range(cfg['Num_modes']):
             _bdy.setFlexibleMotion(i, 1 / amp_modes[i], x_modes[:, 3*i:3*i+3])
+    if 'Transonic_pressure_grad' in cfg:
+        dcp = interpolate_pressure(cfg['Transonic_pressure_grad'], _bdy.getNodes())
+        _bdy.setTransonicPressureGrad(dcp[:, 0])
     _pbl.addBody(_bdy)
 
     # Solver
-    vrb = cfg['Verb_lvl'] if 'Verb_lvl' in cfg else 1
-    _sol = sdpm.Solver(_pbl, vrb)
-    _adj = sdpm.Adjoint(_sol) if use_ad else None
+    vrb = cfg.get('Verb_lvl', 1)
+    _sol = sdpm.Solver(_pbl, vrb) if 'Transonic_pressure_grad' not in cfg else sdpm.SolverTransonic(_pbl, vrb)
+
+    # Gradient
+    _grd = sdpm.Gradient(_sol)
 
     # Return
     return {
@@ -95,5 +98,5 @@ def init_sdpm(cfg, use_ad=False):
         'pbl': _pbl,
         'bdy': _bdy,
         'sol': _sol,
-        'adj': _adj
+        'grd': _grd
     }