Flows around planes

A promising application for mesh adaptation is the computation of compressible flows around aircrafts. This is a collaboration with Dassault Aviation, INRIA (F. Alauzet, Gamma project) and Y. Bourgault (Univ. Ottawa).

During flight, an airplane moves the surronding air in a similar way that a stone thrown into water. The generated waves propagate in every direction with the velocity of the sound (acoustic waves). When a plane travells at a velocity close to the sound velocity (transonic speed), the waves accumulate at the front of the plane increasing the resistivity of the air (sonic barrier). If the velocity increase again, it becomes supersonic and shock waves can appears on the entire structure of the plane.

Fig. Illustration of subsonic, transonic and supersonic velocity

In the later case, the shock waves generate huge stress on the structure and thus need to be predicted correctly. To do that the chair is using mesh adaptation techniques that largely improve the precision of the computed shock waves as illustrated in the animations below.

 

Fig. Visualisation of several transverse cut of the mesh and solution along the main plane axis


 

Fig. Computed shock waves with and without mesh adaptation