Two sets of boundary conditions are applied, as shown in this figure:

Figure 11.7: Nozzle Model Boundary Conditions

The first set of conditions (a) constrains rigid body motions while allowing free radial wall expansion. The second set of conditions (b) provides necessary symmetry constraints on this reduced sector model.

For the symmetry constraints to work properly, nodal degrees of freedom must be rotated to the cylindrical coordinate system.

Only thermal loads are considered in this simulation. The uniform cooling of 1600K is specified via the uniform temperature command (TUNIF).