Version 1.1

Version 1.1 - Automatic differentiation and OpenMDAO interface for flutter computation

This version implements new interfaces and features for computing flutter and derivatives required for flutter analysis and flutter-constrained optimization.

Changes

• Add support for CoDiPack to enable AD
• Add support for flexible motions
• Provide inputs in non-dimensional form
• Add computation of Generalized Aerodynamic Force (GAF)
• Add APIs, mainly for OpenMDAO, see OMFlut

Notes

CoDiPack
Although CoDiPack is an easy to use header-only library, their latest release does not compile with Visual Studio compilers. Therefore, AD cannot be used on Windows for the moment.
Flexible motions
The class Motion has been refactor such that a combination of rigid and flexible motions can be used, under the restriction that the phase of these motions must be the same, see #2 (closed).
Non-dimensional inputs
The freestream velocity magnitude is now equal to 1.0 and the reduced frequencies must be provided instead of the circular frequencies.
Aerodynamic forces
The computation of unsteady surface pressures and forces is now limited to the first harmonic component (convolution products have been removed). The code can also outputs the Generalized Aerodynamic Force matrices which can be used for flutter computation.
APIs
The code components can be initialized using the function init_sdpm. Additionally, the code has been interfaced with OMFlut, built on top of OpenMDAO, for performing flutter-constrained optimization.

Tests

• Ubuntu 22.04 (gcc 11, python 3.10)
• Windows 10 (vs 2019, python 3.8)
• MacOS 12.3 (clang 9, python 3.9)

sdpm/src/sdpmBody.cpp

@@ -155,6 +155,8 @@ Body::Body(Mesh &msh, std::string const &name, std::string const &teName,
     _nLoads.resize(_nodes.size());
     _nLoads1Re.resize(nM, std::vector<std::vector<sdpmVector3d>>(nF, std::vector<sdpmVector3d>(_nodes.size(), sdpmVector3d::Zero())));
     _nLoads1Im.resize(nM, std::vector<std::vector<sdpmVector3d>>(nF, std::vector<sdpmVector3d>(_nodes.size(), sdpmVector3d::Zero())));
+    _iVelocityS.resize(nM, std::vector<sdpmVector3d>(getElements().size(), sdpmVector3d::Zero()));
+    _iVelocityH.resize(nM, std::vector<sdpmVector3d>(getElements().size(), sdpmVector3d::Zero()));
 }
 
 Body::~Body()
@@ -205,8 +207,8 @@ void Body::computeVelocity(size_t m, sdpmVector3d const &ui)
         ucS[i] = _motions[m]->computeSteady(*elems[i], ui);
         ucH[i] = _motions[m]->computeHarmonic(*elems[i]);
     }
-    _iVelocityS.push_back(ucS);
-    _iVelocityH.push_back(ucH);
+    _iVelocityS[m] = ucS;
+    _iVelocityH[m] = ucH;
 }
 
 /**