초록 ▼

Systems, apparatus, and program product and methods for controlling boundary layer flow across an aerodynamic structure which can produce separate regions of flow structures at different strengths by means of dielectric-barrier-discharge (DBD) type plasmas, are provided. An example of such apparatus

Systems, apparatus, and program product and methods for controlling boundary layer flow across an aerodynamic structure which can produce separate regions of flow structures at different strengths by means of dielectric-barrier-discharge (DBD) type plasmas, are provided. An example of such apparatus provides plasma regions that are capable of being individually controlled by voltage and/or frequency, and modulated for the purposes of flow control. The apparatus includes an electrode assembly fitted with electrodes on either side of a dielectric such that different electrode geometries and arrangements create isolated regions of plasmas which results in separate regions of flow structures. These regions may be further controlled and modulated by the use of electronic-switching to produce irregularly shaped flow structures and strengths including those having a primarily vertical component.

대표청구항 ▼

1. An apparatus for controlling boundary layer flow across an aerodynamic structure, the apparatus comprising a dielectric-barrier-discharge electrode assembly to be connected to a surface of an aerodynamic structure, the electrode assembly comprising: an insulating dielectric layer having an enviro

1. An apparatus for controlling boundary layer flow across an aerodynamic structure, the apparatus comprising a dielectric-barrier-discharge electrode assembly to be connected to a surface of an aerodynamic structure, the electrode assembly comprising: an insulating dielectric layer having an environmental fluid facing surface defining a top surface and an aerodynamic structure facing surface defining a bottom surface;a first electrode layer positioned in contact with the top surface of the insulating dielectric layer and having a plurality of oblong voids extending therethrough, each oblong void substantially completely surrounded by a portion of the first electrode layer, the portion of the first electrode substantially completely surrounding each respective one of the plurality of oblong voids substantially defining a perimeter of an extent of the respective oblong void; anda second electrode layer comprising a plurality of separate and spaced apart oblong electrodes defining a plurality of secondary electrodes positioned in contact with the bottom surface of the insulating dielectric layer so that the insulating dielectric layer is positioned between at least substantial portions of the first electrode layer and each of the plurality of spaced apart secondary electrodes, each of the plurality of secondary electrodes positioned beneath a separate one of the plurality of oblong voids to complement the respective separate one of the plurality of oblong voids and positioned laterally substantially within confines of a normal extending along the perimeter of the respective complementing separate one of the plurality of oblong voids;the portion of the first electrode defining the perimeter of the extent of the respective oblong void, the complementing secondary electrode associated therewith, and a respective adjacent portion of the dielectric layer positioned between the surrounding portion of the first electrode and the complementing secondary electrode forming a separate active plasma region of a plurality of active plasma regions, each plasma region dimensioned so that when activated the respective plasma region functions to impart a net velocity to the surrounding environmental fluid having a substantial vertical component normal to and extending away from the portion of the top surface of dielectric layer within the respective oblong void. 2. The apparatus as defined in claim 1, wherein the plurality of active plasma regions form active portions of a plasma actuator, and wherein each plasma region is dimensioned so that when activated, the respective plasma region functions to impart a net velocity to the surrounding environmental fluid which is primarily substantially normal to the portion of the dielectric layer immediately below the respective oblong void. 3. The apparatus as defined in claim 1, wherein the perimeter of each oblong void is substantially pill shaped. 4. The apparatus as defined in claim 1, wherein an outer surface perimeter of each oblong electrode is substantially pill shaped. 5. The apparatus as defined in claim 1, wherein each oblong void has a length and a width, and wherein the width is a minimum of approximately 1 mm to thereby provide sufficient acceleration to the surrounding environmental fluid. 6. The apparatus as defined in claim 1, further comprising a controller configured to perform the operations of: determining an aerodynamic flight profile representing an expected level of crossflow in the boundary layer flow across the aerodynamic structure; and selectively adjusting a pattern of activated plasma regions to thereby effectively adjust spacing between active plasma regions responsive to variations in the level of crossflow, decreasing the effective spacing between activated plasma regions when encountering flow having a higher Reynolds chord number than a certain value, andincreasing the effective spacing between activated plasma regions when encountering boundary layer flow having a lower Reynolds chord number than the certain value. 7. The apparatus as defined in claim 1, further comprising: a controller configured to perform the operation of selectively adjusting a pattern of activated plasma regions to thereby effectively adjust spacing between active plasma regions. 8. The apparatus as defined in claim 7, further comprising: at least one sensor in communication with the controller; andwherein the operation of selectively adjusting a pattern of activated plasma regions is performed responsive to sensor data indicating a current operational flight profile. 9. The apparatus as defined in claim 8, wherein the operation selectively adjusting a pattern of activated plasma regions performed by the controller comprises the operations of: decreasing the effective spacing between activated plasma regions when encountering boundary layer flow having a higher Reynolds chord number than 1.0e6; andincreasing the effective spacing between activated plasma regions when encountering boundary layer flow having a lower Reynolds chord number than 1.0e6. 10. The apparatus as defined in claim 1, further comprising: at least one electrically switchable conductor array positioned to provide electrical current to at least a subset of the plurality of secondary electrodes to thereby produce a plurality of different flow patterns; anda controller operably coupled to the at least one electrically switchable conductor array and configured control formation of the plurality of different flow patterns. 11. The apparatus as defined in claim 10, wherein the plurality of different flow patterns is a plurality of selectively irregularly shaped flow patterns; andwherein the controller is further configured to modulate both voltage and frequency to control formation of the plurality of selectively irregularly shaped flow patterns. 12. The apparatus as defined in claim 1, wherein each oblong void has a length and a width at least partially defining a void surface area for the respective oblong void;wherein each secondary electrode has a dielectric layer-facing surface having a length and a width at least partially defining a surface area of an entire extent of the dielectric layer-facing surface for the respective secondary electrode; andwherein each secondary electrode is configured so that the surface area of the entire extent of the dielectric layer-facing surface is smaller than the void surface area of the complementing oblong void. 13. The apparatus as defined in claim 1, wherein each oblong void has a length and a width at least partially defining a void surface area for the respective oblong void;wherein each secondary electrode has a dielectric layer-facing surface having a length and a width at least partially defining a surface area of an entire extent of the dielectric layer-facing surface for the respective secondary electrode; andwherein a relative size differential between the void area of each oblong void and the surface area of the dielectric layer-facing surface of its complementing secondary electrode is at least partially characterized by the following: the length of each oblong void is substantially larger than the length of the dielectric layer-facing surface of the associated complementing secondary electrode, andthe width of each oblong void is substantially larger than the width of the dielectric layer-facing surface of the associated complementing secondary electrode. 14. The apparatus as defined in claim 1wherein each separate oblong void of the plurality of oblong voids is oriented approximately parallel to each other of the plurality of oblong voids; andwherein each separate oblong void of the plurality of oblong voids is spaced apart from the each other of the plurality of oblong voids at a distance of between approximately 2.0 mm and 2.75 mm. 15. The apparatus as defined in claim 1, wherein the first electrode has a thickness of no more than approximately 1.0 microns to thereby render negligible unactivated flow stream disruption resulting from application of the dielectric barrier discharge electrode assembly to the aerodynamic structure. 16. The apparatus as defined in claim 1, further comprising: additional dielectric material positioned in contact with the top surface of the insulating dielectric and between adjacent portions of the first electrode layer to suppress unwanted discharge regions. 17. The apparatus as defined in claim 1, wherein the plurality of plasma regions is a first plurality of plasma regions;wherein the first electrode layer further includes a plurality of additional voids positioned along and extending from an outer perimeter edge of the first electrode layer;wherein the second electrode layer comprises at least one portion positioned at least partially offset from a center of the additional plurality of voids to thereby form a second plurality of plasma regions; andwherein each plasma region of the second plurality of plasma region is dimensioned so that when activated the respective plasma region functions to impart a net velocity to the surrounding environmental fluid which is primarily substantially tangential to the portion of the dielectric layer immediately below the respective additional void. 18. An apparatus for controlling boundary layer flow across an aerodynamic structure, the apparatus comprising: a dielectric-barrier-discharge electrode assembly integrated with a surface of an aerodynamic structure, the electrode assembly comprising: an insulating dielectric layer having an environmental fluid facing surface defining a top surface and an aerodynamic structure facing surface defining an bottom surface,a first electrode layer positioned in contact with the top surface of the insulating dielectric layer and having a plurality of oblong voids extending therethrough, each oblong void substantially completely surrounded by a portion of the first electrode layer, the portion of the first electrode substantially completely surrounding each respective one of the plurality of oblong voids substantially defining a perimeter of an extent of the respective oblong void, the perimeter of each oblong void being substantially pill shaped, a surface area of the top surface of the insulating dielectric layer within the perimeter of each respective oblong void defining a void area for the respective oblong void, anda second electrode layer comprising a plurality of separate and spaced apart oblong electrodes defining a plurality of secondary electrodes positioned in contact with the bottom surface of the insulating dielectric layer so that the insulating dielectric layer is positioned between at least substantial portions of the first electrode layer and each of the plurality of spaced apart secondary electrodes, each of the plurality of secondary electrodes positioned beneath a separate one of the plurality of oblong voids to complement the respective separate one of the plurality of oblong voids and positioned laterally substantially within confines of a normal extending along the perimeter of the respective complementing separate one of the plurality of oblong voids, each secondary electrode including a dielectric layer-facing surface being substantially pill shaped, a surface area of an entire extent of the dielectric layer-facing surface for the respective secondary electrode being substantially smaller than the void area of the associated complementing oblong void,the portion of the first electrode defining the perimeter of the extent of the respective oblong void, the complementing secondary electrode associated therewith, and a respective adjacent portion of the dielectric layer positioned between the surrounding portion of the first electrode and the complementing secondary electrode forming a separate active plasma region of a plurality of active plasma regions, each plasma region dimensioned so that when activated the respective plasma region functions to impart a net velocity to the surrounding environmental fluid which is primarily substantially normal to the portion of the dielectric layer immediately below the respective oblong void; anda controller configured to perform the operations of: determining a level of turbulence of the boundary layer flow across at least portions of the aerodynamic structure, andselectively adjusting a pattern of activated plasma regions to thereby effectively adjust spacing between active plasma regions responsive to variations in the level of turbulence, decreasing the effective spacing between activated plasma regions when encountering boundary layer flow having a higher Reynolds chord number than a certain value and increasing the effective spacing between activated plasma regions when encountering boundary layer flow having a lower Reynolds chord number than the certain value. 19. A method of controlling boundary layer flow across an airfoil, the method comprising the steps of: applying a first electrode layer to a first surface of an insulating dielectric layer defining a top surface of the insulating dielectric layer, the first electrode layer configured with a plurality of oblong voids extending therethrough, each oblong void substantially completely surrounded by a portion of the first electrode layer, the portion of the first electrode substantially completely surrounding each respective one of the plurality of oblong voids substantially defining a perimeter of an extent of the respective oblong void; andapplying a second electrode layer to a second surface of the insulating dielectric layer opposite the first surface defining a bottom surface of the insulating dielectric layer, the second electrode layer shaped to form a plurality of separate and spaced apart oblong electrodes defining a plurality of secondary electrodes, each of the plurality of secondary electrodes positioned beneath a separate one of the plurality of oblong voids to complement the respective separate one of the plurality of oblong voids and positioned laterally substantially within confines of a normal extending along the perimeter of the respective complementing oblong void;the portion of the first electrode defining the perimeter of the extent of the respective oblong void, the complementing secondary electrode associated therewith, and a respective adjacent portion of the dielectric layer located between the surrounding portion of the first electrode and the complementing secondary electrode forming a separate active plasma region of a plurality of active plasma regions of a dielectric-barrier-discharge electrode assembly, each plasma region dimensioned so that when activated the respective plasma region functions to impart a net velocity to the surrounding environmental fluid having a substantial vertical component normal to and extending away from the portion of the top surface of dielectric layer within the respective oblong void. 20. The method as defined in claim 19, wherein each plasma region is dimensioned so that when activated, the respective plasma region functions to impart a net velocity to the surrounding environmental fluid which is primarily substantially normal to the portion of the dielectric layer immediately below the respective oblong void. 21. The method as defined in claim 19, wherein the perimeter of each oblong void is substantially pill shaped;wherein each oblong void has a length and a width;wherein an outer surface perimeter of each oblong electrode is substantially pill shaped;wherein each secondary electrode has a length and a width; andwherein the width of each oblong void is greater than the width of its respective complementing secondary electrode. 22. The method as defined in claim 19, wherein each oblong void has a length and a width at least partially defining a void area for the respective oblong void; andwherein each secondary electrode has a dielectric layer-facing surface having a length and a width at least partially defining an entire extent of a surface area of the dielectric layer-facing surface for the respective secondary electrode,the entire extent of the surface area of the dielectric layer-facing surface of each oblong electrode being shaped to be substantially smaller than the void area of the associated complementing oblong void. 23. The method as defined in claim 19, wherein the step of applying a first electrode layer to a first surface of an insulating dielectric layer includes applying the first electrode layer so that the first electrode layer has a thickness of no more than approximately 1.0 microns to thereby render negligible unactivated flow stream disruption resulting from the dielectric barrier discharge electrode assembly being connected to the surface of the airfoil; andwherein the method further, comprises the step of connecting the dielectric-barrier-discharge electrode assembly a surface of an airfoil. 24. The method as defined in claim 19, further comprising the steps of: applying an electrically switchable conductor array to the bottom surface of the insulating dielectric layer to provide electrical current to at least a subset of the plurality of secondary electrodes to thereby produce a plurality of different flow patterns; andproducing a plurality of different flow patterns, each different flow pattern associated with a different airfoil operational condition. 25. The method as defined in claim 24, wherein the step of producing a plurality of different flow patterns includes the steps of: decreasing effective spacing between activated plasma regions when encountering boundary layer flow having a higher Reynolds chord number than 1.0e6; andincreasing the effective spacing between activated plasma regions when encountering boundary layer flow having a lower Reynolds chord number than 1.0e6. 26. The method as defined in claim 24, wherein the plurality of different flow patterns is a plurality of selectively irregularly shaped flow patterns; andwherein the method further comprises the step of modulating both voltage and frequency to control formation of the plurality of selectively irregularly shaped flow patterns. 27. The method as defined in claim 19, further comprising the steps of: sensing a level of turbulence of the boundary layer flow across at least portions of the aerodynamic structure, andselectively adjusting a pattern of activated plasma regions to thereby effectively adjust spacing between active plasma regions responsive to variations in the level of turbulence, decreasing the effective spacing between activated plasma regions when encountering boundary layer flow having a higher Reynolds chord number than 1.0e6 and increasing the effective spacing between activated plasma regions when encountering boundary layer flow having a lower Reynolds chord number than 1.0e6. 28. The method as defined in claim 19, further comprising the step of: applying an insulating dielectric material in contact with the top surface of the insulating dielectric and between adjacent portions of the first electrode layer to suppress unwanted discharge regions. 29. The method as defined in claim 19, wherein the plurality of plasma regions is a first plurality of plasma regions;wherein the first electrode layer is further configured with a plurality of additional voids positioned along and extending from an outer perimeter edge of the first electrode layer;wherein the second electrode layer is further configured with at least one portion positioned at least partially offset from a center of the additional plurality of voids to thereby form a second plurality of plasma regions;wherein each plasma region of the second plurality of plasma regions is dimensioned so that when activated the respective plasma regions functions to impart a net velocity to the surrounding environmental fluid which is primarily substantially tangential to the portion of the dielectric layer immediately below the respective additional void; andwherein the method further comprises adjusting a pattern of active plasma regions of the first plurality of plasma regions in combination with a pattern of active plasma regions of the second plurality of plasma regions to control a net direction and velocity of the flow created by the first and the second plurality of plasma regions.