Description:

In this calculation, the fluid-structure-thermal interaction problem of a nose cone in a Mach 3 flow is solved. The angle of attack is 3 degrees. The cone structure deforms due to both mechanical and thermal loads. Three solvers are used to find the solutions for the fluid flow (FEFLO) , the structure temperature field (NASTRAN) and the structural deformations (NASTRAN). The fluid sends the thermal loads (heat-flux) to the CTD code and mechanical loads (pressure and shear stresses) to the CSD code. The CTD code then computes the temperature field in the structure and sends it to the CSD code, which in turn obtains the structural deformations due to heating and the applied mechanical loads. The new position, velocity and temperature of the structure are then passed to the fluid code to impose boundary conditions for the next timestep. This solution process continues iteratively.

The following two figures shows the fluid pressure distribution and the temperature field in the fluid domain, respectively.

The next two figures show the heat flux magnitude and the temperature on the structure, respectively.

Finally, the following images show the structural deformations. The undeformed surface is colored with the magnitude of the displacement field and the deformed surface is rendered in grey.

Observations:

• For this particular case, the deformations due to heating are more important than those due to mechanical loads.
• Very little change in the flow field is observed due to the structural deformations (which are not quite large).
• Due to discrepancies in the fluid and structural grids and to the presence of shock waves, it is important to use conservative load transfer algorithms.
• Since heat-flux and temperature, as well as fluid-loads and structural deformations are conjugate variables (their product yields energy), we find it appealing to transfer loads in one direction (fluid to structure) and deformations of temperatures in the othe direction (structure to fluid). This may help to conserve the total energy in the transfer process.
• To our knowledge this was the first fluid-structure-thermal coupling simulation of this type.