A nozzle whose main flow is annular about a center, truncated cone, and a secondary flow is introduced through the base of the cone. The circulation of this secondary flow and its interaction with the engine exhaust creates an "aerodynamic spike" that behaves much like the ideal, isentropic spike. In addition, the secondary flow re-circulates upward pushing on the base to produce additional thrust. It is this artificial aerodynamic spike for which the Aerospike nozzle is named.