Dual jet emerging lift augmentation system for airfoils and hydrofoils

A fluid foil apparatus comprising:

• a first foil surface section and a second foil surface section, said first foil surface section having a pressurized fluid inlet, said first foil surface section and said second foil surface section being joined so as to be characterized by a leading foil edge, a trailing foil edge, and a chamber between said first foil surface section and said second foil surface section, said first foil surface section and said second foil surface section being connected at said leading foil edge and forming a gap at said trailing foil edge, said gap extending along at least a portion of said trailing foil edge and communicating with said chamber;
• a structure situated in said chamber, said structure including a flat partition section and a bulbous edge section, said flat partition section defining a geometric plane and being characterized by a thickness that is perpendicular to said geometric plane and by a cross-bleed conduit passing through said thickness, said bulbous edge section being characterized by a cylindroid shape and by a diameter that is perpendicular to said geometric plane and that is greater than said thickness, said geometric plane symmetrically dividing said cylindroid shape into two equivalent semi-cylindroid shapes on opposite sides of said geometric plane, said bulbous section unsnugly fitting in said gap so that a first slot and a second slot are formed that are parallel to said geometric plane and so that said geometric plane passes through said gap, said partition section dividing said chamber into a first plenum and a second plenum, said first slot communicating with said first plenum and being demarcated by said first foil surface section and said bulbous edge section, said second slot communicating with said second plenum and being demarcated by said second foil surface section and said bulbous edge section;
• at least one support member, said at least support member associating said first foil surface section, said second foil surface section, and said structure, said cross-bleed conduit being located between said trailing foil edge and said at least one support member;
• and
• a pressurized fluid source for feeding pressurized fluid into said first plenum via said pressurized fluid inlet, wherein simultaneously a first portion of said pressurized fluid exits said first plenum through said first slot and a second portion of said pressurized fluid exits said second plenum through said second slot, said first portion of said pressurized fluid flowing unimpeded between said pressurized fluid inlet and said first slot, said second portion of said pressurized fluid entering said second plenum through said cross-bleed conduit and flowing unimpeded between said cross-bleed conduit and said second slot, said cross-bleed conduit thereby determining said second portion of said pressurized fluid.

A fluid foil apparatus comprising:

• a first foil surface section and a second foil surface section, said first foil surface section having a pressurized fluid inlet, said first foil surface section and said second foil surface section being joined so as to be characterized by a leading foil edge, a trailing foil edge, and a chamber between said first foil surface section and said second foil surface section, said first foil surface section and said second foil surface section being connected at said leading foil edge and forming a gap at said trailing foil edge, said gap extending along at least a portion of said trailing foil edge and communicating with said chamber;
• a structure situated in said chamber, said structure including a flat partition section and a bulbous edge section, said flat partition section defining a geometric plane and being characterized by a thickness that is perpendicular to said geometric plane, said partition section having a cross-bleed conduit that extends through said thickness, said bulbous edge section being characterized by a cylindroid shape and by a diameter that is perpendicular to said geometric plane and that is greater than said thickness, said geometric plane symmetrically dividing said cylindroid shape into two equivalent semi-cylindroid shapes on opposite sides of said geometric plane, said bulbous section unsnugly fitting in said gap so that a first slot and a second slot are formed that are parallel to said geometric plane and so that said geometric plane passes through said gap, said partition section dividing said chamber into a first plenum and a second plenum, said first slot communicating with said first plenum and being demarcated by said first foil surface section and said bulbous edge section, said second slot communicating with said second plenum and being demarcated by said second foil surface section and said bulbous edge section;
• at least one support member, said at least one support member associating said first foil section, said section foil section, and said structure, said cross-bleed conduit being located between said trailing foil edge and said at least one support member;
• a pressurized fluid source for feeding pressurized fluid into said first plenum;
• a valve for regulating flow of said pressurized fluid into said first plenum;
• a controller for controlling said valve so that:
• said pressurized fluid enters said first plenum via said valve;
• a first portion of said pressurized fluid entering said first plenum does not enter said second plenum via said cross-bleed conduit;
• a second portion of said pressurized fluid entering said first plenum enters said second plenum via said cross-bleed conduit;
• simultaneously, said first portion of said pressurized fluid exits said first plenum through said first slot and said second portion of said pressurized fluid exits said second plenum through said second slot;
• said first portion of said pressurized fluid is characterized by a first momentum flux upon exiting said first plenum through said first slot;
• said second portion of said pressurized fluid is characterized by a second momentum flux upon exiting said second plenum through said second slot;
• said second momentum flux is less than said first momentum flux;
• said first portion of said pressurized fluid that has exited said first plenum through said first slot is to some degree entrained in accordance with a Coanda effect by said bulbous edge section;
• the entrained said first portion of said pressurized fluid thereby forms a fluid jet wall;
• said second portion of said pressurized fluid that has exited said second plenum through said second slot influences the direction of said fluid jet wall.