Compressible Flow over Missile Projectile

Isometric view of the missile.

Enclosure and missile.

This is an assignment for my ME-441 Computer Simulation and Analysis class. In the Computer Simulation and Analysis class ANSYS Workbench and Discovery AIM were used extensively to simulate. Instructions were provided, and sometimes the models, either from Creo Parametric or SolidWorks, were provided as well. Some assignments however need the objects to be modelled from scratch or modified before hand.

The assignment

In this assignment, a model of a missile undergoes a compressible subsonic air flow using ANSYS AIM Fluid Flow.

The theoretical calculations goes:

Coefficient of Drag

C_D = F_D / (0.5 * p * A * v^2)

When editing the geometry, a massive enclosure is modelled around the missile. From the missile's nose cone, one end of the enclosure is 10 m away. From the missile's nozzle, the other end of the enclosure is 30 m away. The radius of the enclosure is 20 m.

After the enclosure has been modeled, it is cut in half twice (vertically and horizontally) until only a quarter of its self is left, as seen in the image on the left. When meshing, the boundary layer and face sizing are applied over the missile seen on the left. An edge sizing is applied at the edge were the missile sits. The element shape is set to tetrahedron.

The boundary conditions of the enclosure includes: the inlet, outlet, two symmetries, and two walls. The inlet, located on the left face of the enclosure facing the missile nose, is a subsonic, pressure based inlet with a gauge total pressure of 28,000 Pa and a temperature of 35.85 C. The outlet, located on the opposite end face, is a subsonic, pressure based outlet with a gauge static pressure of 0 Pa. The two symmetry conditions are the large flat faces of the enclosure when it got halved. The two walls of the enclosure are the round face and the missile itself.

Results