Engine placement for sonic boom mitigation

The achievement of unrestricted overland supersonic flight will require significant reductions in the level of the sonic boom that is propagated by the airplane to the ground. During this one year DARPA funded study the beneficial effects of placing the engines above rather than below the wing were investigated using CFD analysis methods. The study results have shown that the over wing engine placement does benefit the sonic boom in that the inlet shock is partially shielded by the wing. The higher velocity flow field over the wing also results in more highly swept inlet shocks which have less of a tendency to coalesce the boom signature into the classical N-wave and allows a shaped signature to be propagated to the ground.