Setting up Morpher Displacement for the Control Points

The Adjoint Mesh Deformation model calculates the new positions of the control points based on the morpher displacement you specify.

You specify morpher displacements for the control points using adjoint mesh sensitivity, so that the cost function Downforce increases.

For this tutorial, you use a first-order Steepest Descent algorithm with a step size of 0.0001 to update the point set positions. To update the control point positions for the shape optimization cycles, you take into account the total displacement of a control point from its original position. You achieve this by associating a user-defined field function that defines the Steepest Descent deformation with the morpher. This user-defined field function uses a built-in field function for the cumulative morpher displacement.

To define the displacement field function:
  1. Right-click the Automation > Field Functions node and select New > Vector.
  2. Rename this field function to Displacement and set the following properties:
    Property Setting
    Function Name Displacement
    Definition $${CumulativeMorpherDisplacement} + 1.e-04*$${Adjoint1::CoordAdjoint}

    The field function is defined such that it multiplies the step size of 0.0001 with the Adjoint of Downforce w.r.t. Position field function. You obtain this field by computing the mesh sensitivity of the Downforce cost function on the point sets (see Computing the Mesh Sensitivity).

  3. Multi-edit the Point Sets > Lower > Physics Values and the Point Sets > Upper > Physics Values nodes and set the following properties:
    Node Property Setting
    Morpher: Displacement Method Field Function
    Vector Function Displacement