Malleatus

Malleatus is a grid-deformer for use with Cobalt. It calculates the movement of all grid points based on user-coded deformation of the grid boundaries. Malleatus receives information such as grid points, cell connectivity and boundary information and passes that along to the user-coded boundary movement; after receiving the new boundary locations, it performs the grid deformation and passes the new grid to Cobalt. The user-coded boundary movement is compiled as a run-time library and linked to Malleatus/Cobalt.

An example of a solution with grid deformation is the F-18C undergoing bending in the wing and the vertical tail. The wing deflects about 39 inches at the tip while the vertical tail has a maximum tip deflection of 24 inches.

For further information about Malleatus, read the following posts:

Bob’s Research Corner: Malleatus, part 1

BRC: Malleatus, part 2

BRC: Malleatus, part 3

The equilibrium air module uses the curve fits of Tannehill, et al. to calculate the thermodynamic and molecular properties of air when intermolecular forces become important. As temperature becomes large, dissociation and eventually ionization occurs. The thermodynamic properties of air become dependent on two variables (T = T(P,e)). For hypersonic flows, this has the effect of weakening the strength of a shock wave. The table below shows the temperatures at which dissociation and ionization become important. Molecular vibrations start occurring around T=600 K which is the temperature value where starts γ changing.

Temperature Range	Chemical Composition
T < 2500 K	78% N₂, 21% O₂
2500 K < T < 4000 K	Oxygen dissociation regime. Some NO is formed
4000 K < T < 8000 K	Nitrogen dissociation regime. Oxygen is fully dissociated.
8000 K < T	Ionization of atomic constituents occurs