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/src/sdpmMotion.cpp

@@ -22,20 +22,17 @@ using namespace sdpm;
 
 Motion::Motion(size_t n) : sdpmObject(),
                            _aAmp(0.), _hAmp(0.),
-                           _xRef(0.), _zRef(0.),
-                           _mAmp(0.), _dzMod(n, 0.), _rxMod(n, 0.), _ryMod(n, 0.)
+                           _dzMod(n, 0.), _rxMod(n, 0.), _ryMod(n, 0.)
 {
 }
 
 /**
  * @brief Set rigid motion parameters
  */
-void Motion::setRigid(double aAmp, double hAmp, double xRef, double zRef)
+void Motion::setRigid(double aAmp, double hAmp)
 {
     _aAmp = aAmp;
     _hAmp = hAmp;
-    _xRef = xRef;
-    _zRef = zRef;
 }
 
 /**
@@ -43,12 +40,11 @@ void Motion::setRigid(double aAmp, double hAmp, double xRef, double zRef)
  */
 void Motion::setFlexible(double mAmp, std::vector<std::vector<double>> const &xMod, std::vector<Node *> const &nodes)
 {
-    _mAmp = mAmp;
     for (size_t i = 0; i < nodes.size(); ++i)
     {
-        _dzMod[nodes[i]->getId() - 1] = xMod[i][0];
-        _rxMod[nodes[i]->getId() - 1] = xMod[i][1];
-        _ryMod[nodes[i]->getId() - 1] = xMod[i][2];
+        _dzMod[nodes[i]->getId() - 1] = mAmp * xMod[i][0];
+        _rxMod[nodes[i]->getId() - 1] = mAmp * xMod[i][1];
+        _ryMod[nodes[i]->getId() - 1] = mAmp * xMod[i][2];
     }
 }
 
@@ -67,7 +63,7 @@ sdpmVector3d Motion::computeSteady(Element const &e, sdpmVector3d const &ui)
     {
         sdpmDouble rx = _rxMod[n->getId() - 1];
         sdpmDouble ry = _ryMod[n->getId() - 1];
-        flex += _mAmp * sdpmVector3d(ui(2) * ry, ui(2) * rx, -ui(0) * ry - ui(1) * rx) / e.getNodes().size();
+        flex += sdpmVector3d(ui(2) * ry, ui(2) * rx, -ui(0) * ry - ui(1) * rx) / e.getNodes().size();
     }
     return rigd + flex;
 }
@@ -75,14 +71,14 @@ sdpmVector3d Motion::computeSteady(Element const &e, sdpmVector3d const &ui)
 /**
  * @brief Compute the harmonic part of the motion induced velocity on an element of the body
  */
-sdpmVector3d Motion::computeHarmonic(Element const &e)
+sdpmVector3d Motion::computeHarmonic(Element const &e, sdpmDouble xRef, sdpmDouble zRef)
 {
     // Rigid contribution
-    sdpmVector3d cg = e.getCompressibleCg();
-    sdpmVector3d rigd(-_aAmp * (cg(2) - _zRef), 0., _aAmp * (cg(0) - _xRef) + _hAmp);
+    sdpmVector3d cg = e.getCg();
+    sdpmVector3d rigd(-_aAmp * (cg(2) - zRef), 0., _aAmp * (cg(0) - xRef) + _hAmp);
     // Flexible contribution
     sdpmVector3d flex = sdpmVector3d::Zero();
     for (auto n : e.getNodes())
-        flex += _mAmp * sdpmVector3d(0., 0., _dzMod[n->getId() - 1]) / e.getNodes().size();
+        flex += sdpmVector3d(0., 0., _dzMod[n->getId() - 1]) / e.getNodes().size();
     return rigd + flex;
 }