초록 ▼

A system for reducing overall drag of a mobile platform includes a surface on which an airflow forms a boundary layer and a generally normal shockwave. The airflow is at a first velocity that is one of transonic and supersonic. An oscillating jet injects and extracts a jet flow through the surface.

A system for reducing overall drag of a mobile platform includes a surface on which an airflow forms a boundary layer and a generally normal shockwave. The airflow is at a first velocity that is one of transonic and supersonic. An oscillating jet injects and extracts a jet flow through the surface. The jet flow is at a second velocity that is substantially less than the first velocity. A recirculation region is upstream of the normal shockwave and is disposed at least partially in the boundary layer. The recirculation region is established at least by the oscillating jet. A generally oblique wave is established by the recirculation region and weakens the normal shockwave to reduce the overall drag experienced by the surface.

대표청구항 ▼

What is claimed is: 1. A system for reducing overall drag of an airborne mobile platform, the system comprising:a surface having a spanwise length on which an airflow forms a boundary layer and a generally normal shockwave, wherein said airflow is at a first velocity that is one of transonic and sup

What is claimed is: 1. A system for reducing overall drag of an airborne mobile platform, the system comprising:a surface having a spanwise length on which an airflow forms a boundary layer and a generally normal shockwave, wherein said airflow is at a first velocity that is one of transonic and supersonic;a plurality of oscillating jets formed in an array that each at least one of inject and extract a jet flow through said surface, wherein each said jet flow is at a second velocity that is substantially less than said first velocity;a controller that controls operation of the oscillating jets of the array;the controller controlling the plurality of oscillating jets of the array to establish a recirculation region of a controllable dimension, using selected ones of the jets, that is upstream of said normal shockwave and that is disposed at least partially in said boundary layer, and said selected ones of said oscillating jets generating a generally oblique wave that is substantially weaker than said normal shockwave but which weakens said normal shockwave;said array of said plurality of oscillating jets including at least a first set of oscillating jets and a second set of oscillating jets arranged parallel to said first set of oscillating jets;said first set extends in generally a spanwise direction and is associated with a first chord position that is upstream from said second set that is associated with a second chord position;each of said first and second sets switchable between an active condition and an inactive condition based on one of a condition of said airflow, an orientation of said surface relative to said airflow and a combination thereof;wherein said oscillating jets oscillate between blowing and suction and said second velocity of said jet flows oscillate between a maximum blowing velocity and a maximum sucking velocity; andwherein the controller adjusts at least two of said maximum blowing velocity, said maximum sucking velocity and a frequency of oscillation based on at least one of a flow condition, an orientation of said surface relative to said airflow, and a strength of said oscillating jets.