Plasma Actuator

Abstract

To provide a plasma actuator which can generate an induction flow which is directed in the same direction along a dielectric surface in a first surface (the front surface) and a second surface (back surface) of a dielectric.SOLUTION: The plasma actuator includes: a dielectric; a first electrode provided in a first surface of the dielectric; a second electrode provided in a second surface facing the first surface of the dielectric; and a power source for generating a predetermined AC voltage. The plasma actuator further includes a third electrode provided in the dielectric . The third electrode is arranged in a direction displaced to one of the in-plane directions of the dielectric with respect to the first electrode and the second electrode. The power source applies a voltage between the first electrode and the third electrode and applies a voltage between the second electrode and the third electrode. The first electrode and the second electrode at least receive a voltage with the same polarity.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a plasma actuator, and more particularly to a plasma actuator that can generate induced flows that are aligned in the same direction along a dielectric surface on both a first surface (front surface) and a second surface (rear surface) of the dielectric. [Background technology]

[0002] Conventionally, an automotive air conditioner that smoothly changes the direction of air blown out from an air outlet opened inside the vehicle cabin has been proposed (see Patent Document 1). In this automotive air conditioner, a plasma actuator is used as an air drive source to change the direction of air flow (see Figure 3 of Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-65463 Summary of the Invention [Problem to be solved by the invention]

[0004] In a plasma actuator such as that shown in FIG. 3 of Patent Document 1, when a high AC voltage (e.g., 1 kV or more) is applied between two electrodes provided on a first surface (front surface) and a second surface (rear surface) of a dielectric, plasma is generated in principle at the electrodes on both the first surface (front surface) and the second surface (rear surface) of the dielectric, generating an induced flow (air flow). However, the flow directions of these induced flows are opposite on the first surface (front surface) side and the second surface (rear surface) side of the dielectric. Therefore, when such a plasma actuator is used as an air drive source, there is a problem in that only the induced flow generated at the electrode on one side can be utilized.

[0005] The present invention has been made in consideration of the problems associated with the prior art, and aims to provide a plasma actuator that can generate induced flows that are aligned in the same direction along the dielectric surface on both the first surface (front surface) and the second surface (rear surface) of the dielectric. [Means for solving the problem]

[0006] As a result of extensive research into achieving the above-mentioned object, the inventors discovered that the above-mentioned object can be achieved by providing a third electrode in a dielectric, displacing the third electrode relative to the first and second electrodes, applying a voltage between the first and third electrodes and also applying a voltage between the second and third electrodes, and setting the first and second electrodes to a predetermined voltage state, thereby completing the present invention.

[0007] That is, the plasma actuator of the present invention comprises a dielectric, a first electrode provided on a first surface of the dielectric, a second electrode provided on a second surface of the dielectric opposite to the first surface, and a power supply that generates a predetermined AC voltage. This plasma actuator further comprises a third electrode provided in the dielectric. The third electrode is arranged offset in one of the in-plane directions of the dielectric relative to the first and second electrodes. The power supply applies a voltage between the first and third electrodes and also applies a voltage between the second and third electrodes. The first and second electrodes at least have a state in which the polarity of the applied voltage is the same. However, the potential difference between the first electrode and the third electrode is different from the potential difference between the second electrode and the third electrode. do. [Effects of the Invention]

[0008] According to the present invention, a third electrode is provided in the dielectric, the third electrode is positioned offset with respect to the first and second electrodes, a voltage is applied between the first and third electrodes, and a voltage is applied between the second and third electrodes, and the first and second electrodes are set to a predetermined voltage state. As a result, a plasma actuator can be provided that can generate induced flows that are aligned in the same direction along the dielectric surface on both the first surface (front surface) and the second surface (rear surface) of the dielectric. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing a first embodiment of a plasma actuator according to the present invention. [Figure 2] 4 is a cross-sectional view showing a state in which a third electrode in the plasma actuator of the first embodiment is provided in a dielectric. FIG. [Figure 3] FIG. 4 is a cross-sectional view showing a second embodiment of the plasma actuator. [Figure 4] FIG. 10 is a cross-sectional view showing a third embodiment of the plasma actuator. [Figure 5] FIG. 10 is a cross-sectional view showing a fourth embodiment of the plasma actuator. [Figure 6] FIG. 10 is a cross-sectional view showing an example of a fifth embodiment of a plasma actuator. [Figure 7] FIG. 10 is a cross-sectional view showing another example of the fifth embodiment of the plasma actuator. [Figure 8] FIG. 10 is a cross-sectional view showing a sixth embodiment of the plasma actuator. [Figure 9] FIG. 10 is a cross-sectional view showing a seventh embodiment of the plasma actuator. [Figure 10] FIG. 13 is a cross-sectional view showing an eighth embodiment of the plasma actuator. DETAILED DESCRIPTION OF THE INVENTION

[0010] The plasma actuator of the present invention will be described in detail below with reference to the drawings. Note that the dimensional ratios of the drawings cited below are exaggerated for the sake of explanation and may differ from the actual ratios. Also, in the following explanation, for the sake of explanation, the "first surface" and the "second surface" may be simply referred to as the "front surface" and the "rear surface," respectively, and the "first electrode," "second electrode," and "third electrode" may be simply referred to as the "front surface electrode," "rear surface electrode," and "intermediate electrode," respectively.

[0011] First Embodiment Fig. 1 is a cross-sectional view of a plasma actuator 1 of this embodiment taken along the flow direction of an induced flow F. As shown in Fig. 1, the plasma actuator 1 of this embodiment includes a dielectric 10, a first electrode (surface electrode) 20 provided on a first surface (front surface) 10A (top surface in the figure) of the dielectric 10, a second electrode (rear surface electrode) 30 provided on a second surface (rear surface) 10B of the dielectric 10 that faces the first surface (front surface), and a power supply 60 (61, 62) that generates a predetermined AC voltage.

[0012] The plasma actuator 1 of this embodiment further includes a third electrode (intermediate electrode) 40 provided inside the dielectric 10. Because such a third electrode (intermediate electrode) 40 is provided, in this embodiment, the first electrode (front surface electrode) 20, the second electrode (rear surface electrode) 30, and the third electrode (intermediate electrode) 40 are arranged as follows:

[0013] In this embodiment, in a plan view (when viewed from the direction of arrow Z in the figure), the first electrode (surface electrode) 20 and the second electrode (back electrode) 30 are arranged in positions that completely overlap and face each other via the dielectric 10. However, the present invention is not limited to this arrangement, and for example, in a plan view, the first electrode (surface electrode) 20 and the second electrode (back electrode) 30 may be arranged in opposing positions with a dielectric 10 interposed therebetween so that they partially overlap (see FIG. 7).

[0014] In this embodiment, the third electrode (intermediate electrode) 40 is arranged offset in one of the in-plane directions of the dielectric 10 (to the right in the figure) relative to the first electrode (surface electrode) 20 and the second electrode (back electrode) 30 so that the third electrode (intermediate electrode) 40 does not overlap the first electrode (surface electrode) 20 and the second electrode (back electrode) 30 in a planar view. However, the present invention is not limited to this. For example, although not shown, the third electrode (intermediate electrode) 40 may be arranged shifted in one of the in-plane directions so that a portion of the third electrode (intermediate electrode) 40 overlaps with the first electrode (surface electrode) 20 and the second electrode (back electrode) 30 in a planar view.

[0015] In this embodiment having the above-described structure, the power supply 60 (61, 62) applies a voltage between the first electrode (surface electrode) 20 and the third electrode (intermediate electrode) 40, and also applies a voltage between the second electrode (rear electrode) 30 and the third electrode (intermediate electrode) 40.

[0016] In this embodiment, the polarities of the voltages applied to the first electrode (front surface electrode) 20 and the second electrode (rear surface electrode) 30 are the same (positive and positive in the figure), and the voltage applied to the third electrode (intermediate electrode) 40 is grounded. In this embodiment, an induced flow F is generated that flows to the right in the figure. However, the present invention is not limited to this, and for example, the first electrode (front surface electrode) and the second electrode (rear surface electrode) do not necessarily have to have the same polarity of their voltages at all times (positive and positive, negative and negative, ground and ground), and the above-mentioned effects can be achieved by at least having the same polarity of their voltages between the first electrode (front surface electrode) 20 and the second electrode (rear surface electrode) 30. The voltage of the third electrode (intermediate electrode) may also be positive, negative, or ground.

[0017] The electrodes in the figure are electrically connected to a power supply 60 (61, 62) via wiring 70 (71, 72, 73, 74). The arrangement of this wiring 70 can be changed as appropriate within the range in which the plasma actuator functions.

[0018] Next, the advantages of this embodiment will be described. In the plasma actuator 1 of this embodiment, the first electrode (surface electrode) 20, the second electrode (rear electrode) 30, and the third electrode (intermediate electrode) 40 are arranged as described above. For example, an AC voltage is applied between the first electrode (surface electrode) 20 and the third electrode (intermediate electrode) 40 by the above-described power supply 60 (61, 62), and also between the second electrode (rear electrode) 30 and the third electrode (intermediate electrode) 40. As a result, plasma P is generated on the right side of the first electrode (surface electrode) 20 and the second electrode (rear electrode) 30 in the drawing. Ionized charges in this plasma P are attracted by an electric field (electric force lines, not shown) extending from the first electrode (surface electrode) 20 and the second electrode (rear electrode) 30 toward the third electrode (intermediate electrode) 40. Therefore, the plasma actuator 1 of this embodiment can generate an induced flow F aligned in the same direction (to the right in the drawing) along the dielectric 10 on both the first surface (surface electrode) 10A side and the second surface (rear electrode) 10B side of the dielectric 10.

[0019] Furthermore, in the plasma actuator 1 of this embodiment, there is at least a state in which the polarity of the voltage applied to the first electrode (front surface electrode) 20 and the second electrode (rear surface electrode) 30 is the same, so that the electric field lines (not shown) extending from the first electrode (front surface electrode) 20 to the third electrode (intermediate electrode) 40 and the electric field lines (not shown) extending from the second electrode (rear surface electrode) 30 to the third electrode (intermediate electrode) 40 cancel each other out. Therefore, the plasma actuator 1 of this embodiment can reduce the parasitic capacitance that does not contribute to the generation of the induced flow F, thereby reducing power consumption.

[0020] Therefore, plasma actuator 1 of this embodiment can reduce power consumption compared to when two plasma actuators such as those shown in Figure 3 of Patent Document 1 are used. Therefore, plasma actuator 1 of this embodiment can generate induced flow F in the same direction along dielectric 10 on both the first surface (front surface) 10A side and the second surface (rear surface) 10B side of dielectric 10 with lower power consumption than when two plasma actuators such as those shown in Figure 3 of Patent Document 1 are used.

[0021] Furthermore, the above-described plasma actuator can be suitably used in, for example, an airflow control device or a cooling device.

[0022] The materials and specifications of each component will be described in detail below.

[0023] (dielectric) The material of the dielectric 10 is not particularly limited, and examples thereof include resin materials such as acrylic, polycarbonate, polyester, polyimide, fluororesin, and silicone resin, and inorganic materials such as glass and ceramic. These may be used alone or in combination of two or more. The shape of the dielectric 10 is not particularly limited, and examples thereof include a plate shape.

[0024] (1st electrode (front electrode), 2nd electrode (back electrode), 3rd electrode (intermediate electrode)) The material for the first electrode (surface electrode) 20 is not particularly limited as long as it is a common electrode material, and various materials can be used, including conductors such as copper, nickel, gold, platinum, and aluminum. These may be used alone or in combination of two or more. The second electrode (rear electrode) 30 and the third electrode (intermediate electrode) 40 may be made of the same material as the first electrode (surface electrode) 20 described above. The first electrode (surface electrode) 20, the second electrode (rear electrode) 30, and the third electrode (intermediate electrode) 40 may be the same or different.

[0025] When providing the third electrode (intermediate electrode) 40 in the dielectric 10, for example, a method of filling it with resin or a method of sandwiching the third electrode (intermediate electrode) 40 between the first dielectric 11 and the second dielectric 13 and bonding them while evacuating to prevent voids from forming can be used, as shown in Figure 2.

[0026] (power supply, wiring) Any power supply that can be used in a conventionally known plasma actuator can be used as the power supply 60. For example, an AC power supply capable of applying a high voltage of 1 kV or more, more specifically, an AC power supply such as a high frequency power supply that can apply a high voltage of 1 kV or more and swings between positive and negative polarities, can be used. Note that, as the wiring 70 that electrically connects the above-described electrodes (20, 30, 40) and the power supply 60, any wiring that can be used in a conventionally known plasma actuator can be used as appropriate.

[0027] 3 to 10 are diagrams illustrating second to eighth embodiments of the plasma actuator of the present invention. In the following embodiments, the same components as in the first embodiment are given the same reference numerals, and detailed descriptions of the invention are omitted.

[0028] Second Embodiment 3, the plasma actuator 2 of this embodiment has the same configuration as the plasma actuator 1 of the first embodiment, except that the surface electrode 20 and the back electrode 30 are at the same potential. In this embodiment, wiring 70 (71) from the power supply 60 is electrically connected to the surface electrode 20 and the back electrode 30, thereby making the surface electrode 20 and the back electrode 30 at the same potential.

[0029] Next, the advantages of this embodiment will be described. In the plasma actuator 2 of this embodiment, the front electrode 20 and the back electrode 30 have the same potential, so the electric field lines (not shown) from the front electrode 20 to the intermediate electrode 40 and the electric field lines (not shown) from the back electrode 30 to the intermediate electrode 40 cancel each other out more than in the case of the plasma actuator 1 of the first embodiment. As a result, the parasitic capacitance in the plasma actuator 2 of this embodiment is reduced compared to the parasitic capacitance in the plasma actuator 1 of the first embodiment. As a result, the plasma actuator 2 of this embodiment can further reduce power consumption compared to the plasma actuator of the first embodiment, in addition to the advantages of the first embodiment.

[0030] <Third embodiment> 4, the plasma actuator 3 of this embodiment has the same configuration as the plasma actuators 1 and 2 of the first and second embodiments, except that the front and back electrodes are combined to form an integrated electrode 50 that penetrates the dielectric 10. In this embodiment, wiring 70 (71) from the power source 60 is electrically connected to the integrated electrode 50. The integrated electrode 50 can be made of the same material as the surface electrode 20 described above.

[0031] Next, the advantages of this embodiment will be described. In the plasma actuator 3 of this embodiment, the front and back electrodes are physically combined to form an integrated electrode 50 made of a conductor that penetrates the dielectric 10, so that the electric field (electric lines of force) that exist between the front and back electrodes 20 and 30 shown in FIG. 1 or 2 does not exist in the integrated electrode 50. As a result, the parasitic capacitance in the plasma actuator 3 of this embodiment is reduced compared to the parasitic capacitance in the plasma actuators 1 and 2 of the first or second embodiment. As a result, the plasma actuator 3 of this embodiment can further reduce power consumption compared to the plasma actuators of the first or second embodiment, in addition to the advantages of the first embodiment.

[0032] <Fourth embodiment> 5, the plasma actuator 4 of this embodiment has the same configuration as the plasma actuator 1 of the first embodiment, except that the potential difference (V1-V3) between the front electrode 20 and the intermediate electrode 40 is different from the potential difference (V2-V3) between the rear electrode 30 and the intermediate electrode 40. Here, V1, V2, and V3 in the figure are the potentials of the front electrode 20, the rear electrode 30, and the intermediate electrode 40, respectively.

[0033] Next, the advantages of this embodiment will be described. In the plasma actuator 4 of this embodiment, the above-mentioned power supply 60 (61, 62) makes the potential difference (V1-V3) between the front surface electrode 20 and the intermediate electrode 40 different from the potential difference (V2-V3) between the back surface electrode 30 and the intermediate electrode 40. Therefore, in addition to the advantages of the first embodiment, the plasma actuator 4 of this embodiment can change the relationship between the strength of the induced flow F on the front surface 10A side of the dielectric 10 and the strength of the induced flow F on the back surface 10B side of the dielectric 10.

[0034] More specifically, the larger the absolute value of the potential difference between the electrodes, the stronger the plasma emission intensity and the electric field between the electrodes, and thus a relatively strong induced flow F is generated on either the front surface 10A side or the back surface 10B side of the dielectric 10. For example, when the absolute value of the potential difference (V1-V3) between the front surface electrode 20 and the intermediate electrode 40 is larger than the absolute value of the potential difference (V2-V3) between the back surface electrode 30 and the intermediate electrode 40, the wind speed of the induced flow F on the front surface 10A side is greater than the wind speed of the induced flow F on the back surface 10B side of the dielectric 10. Therefore, when it is desired to make the wind speed of the induced flow F on the front surface 10A side greater than the wind speed of the induced flow F on the back surface 10B side of the dielectric 10, a desired wind speed can be obtained.

[0035] On the other hand, for example, when the absolute value of the potential difference (V1-V3) between the front electrode 20 and the intermediate electrode 40 is smaller than the absolute value of the potential difference (V2-V3) between the back electrode 30 and the intermediate electrode 40, the wind speed of the induced flow F on the back surface 10B side of the dielectric 10 is greater than the wind speed of the induced flow F on the front surface 10A side of the dielectric 10. Therefore, when it is desired to make the wind speed of the induced flow F on the back surface 10B side of the dielectric 10 greater than the wind speed of the induced flow F on the front surface 10A side of the dielectric 10, a desired wind speed can be obtained.

[0036] Fifth Embodiment As shown in Figures 6 and 7, the plasma actuator 5 (5A, 5B) of this embodiment has the same configuration as the plasma actuator 1 of the first embodiment, except that the shortest distance between the intermediate electrode 40 and the surface electrode 20 is different from the shortest distance between the intermediate electrode 40 and the back electrode 30.

[0037] More specifically, in plasma actuator 5A shown in Fig. 6, the position of intermediate electrode 40 in dielectric 10 is shifted toward front surface 10A (upward in the figure) in the thickness direction of dielectric 10 (upward in the figure). Also, in plasma actuator 5B shown in Fig. 7, the position of back surface electrode 30 is shifted in the in-plane direction of dielectric 10 (leftward in the figure) in a direction away from the position of intermediate electrode 40 relative to the position of front surface electrode 20.

[0038] Next, the advantages of this embodiment will be described. In the plasma actuator 5 of this embodiment, the shortest distance between the intermediate electrode 40 and the front surface electrode 20 is different from the shortest distance between the intermediate electrode 40 and the back surface electrode 30. Therefore, the shorter the inter-electrode distance, the stronger the plasma emission intensity and the stronger the electric field between the electrodes. As a result, in addition to the advantages of the first embodiment, the plasma actuator 5 of this embodiment can change the relationship between the strength of the induced flow F on the front surface 10A side of the dielectric 10 and the strength of the induced flow F on the back surface 10B side of the dielectric 10.

[0039] In plasma actuator 5A shown in Fig. 6, the shortest distance between intermediate electrode 40 and front surface electrode 20 is shorter than the shortest distance between intermediate electrode 40 and back surface electrode 30, so a relatively strong induced flow F is generated on the front surface 10A side of dielectric 10. Therefore, in plasma actuator 5A shown in Fig. 6, a desired wind speed can be obtained when it is desired to make the wind speed of induced flow F on the front surface 10A side of dielectric 10 faster than the wind speed of induced flow F on the back surface 10B side.

[0040] On the other hand, although not shown, for example, in a case where it is desired to make the wind speed of the induced flow F on the back surface 10B side of the dielectric 10 greater than the wind speed of the induced flow F on the front surface 10A side, the position of the intermediate electrode 40 in the dielectric 10 may be shifted toward the back surface 10B side (lower in the drawing) in the thickness direction of the dielectric 10. Furthermore, although not shown, at least one of the front surface electrode 20 and the back surface electrode 30 may be embedded in the dielectric 10 as long as they are exposed on the front surface 10A and the back surface 10B, respectively.

[0041] Furthermore, for the same reasons as those described above, the plasma actuator 5B shown in FIG. 7 can obtain the desired wind speed when it is desired to make the wind speed of the induced flow F on the front surface 10A side of the dielectric 10 greater than the wind speed of the induced flow F on the back surface 10B side.

[0042] On the other hand, although not shown, for example, if it is desired to make the wind speed of the induced flow F on the back surface 10B side of the dielectric 10 greater than the wind speed of the induced flow F on the front surface 10A side, the position of the front surface electrode 20 can be shifted in the in-plane direction of the dielectric 10 in a direction away from the position of the intermediate electrode 40 (to the left in the figure) relative to the position of the back surface electrode 30.

[0043] Sixth Embodiment 8, the plasma actuator 6 of this embodiment has the same configuration as the plasma actuator 1 of the first embodiment, except that at least a portion of the intermediate electrode 40 is exposed on the surface 10A side of the dielectric 10. In this embodiment, a cutout portion 10C is provided in the dielectric 10, so that at least a portion of the intermediate electrode 40 is exposed on the surface 10A side of the dielectric 10. However, the present invention is not limited to this, and for example, although not shown, at least a part of the intermediate electrode 40 may be exposed on the rear surface 10B side of the dielectric 10, or on both the front surface 10A side and the rear surface 10B side. When at least a part of the intermediate electrode 40 is exposed on both the front surface 10A side and the rear surface 10B side, the exposed positions in the in-plane direction of the dielectric 10 (the left-right direction in the drawing) may be the same or different.

[0044] Next, the advantages of this embodiment will be described. In the plasma actuator 6 of this embodiment, electric field lines (not shown) are hardly canceled out in the air (not shown) at the cutout 10C that exposes at least a portion of the intermediate electrode 40, so the electric field is hardly weakened. Therefore, charges ionized in the plasma P on the surface 10A side of the dielectric 10 are strongly pulled toward the cutout 10C. As a result, in addition to the advantages of the first embodiment, the plasma actuator 6 of this embodiment can increase the strength of the induced flow F on the surface 10A side of the dielectric 10, in other words, increase the wind speed of the induced flow F. As a result, when it is desired to increase the wind speed of the induced flow F on the surface 10A side, a desired wind speed can be obtained.

[0045] Although not shown, by exposing at least a portion of the intermediate electrode 40 on the back surface 10B side of the dielectric 10, the strength of the induced flow F on the back surface 10B side of the dielectric 10 can be increased, in other words, the wind speed of the induced flow F can be increased. As a result, when the wind speed of the induced flow F on the back surface 10B side of the dielectric 10 is desired to be increased, a desired wind speed can be obtained. Furthermore, although not shown, by exposing at least a portion of the intermediate electrode 40 on both the front surface 10A side and the back surface 10B side of the dielectric 10, the strength of the induced flow F on both the front surface 10A side and the back surface 10B side of the dielectric 10 can be increased, in other words, the wind speed of the induced flow F can be increased. As a result, when the wind speed of the induced flow F on both the front surface 10A side and the back surface 10B side of the dielectric 10 is desired to be increased, a desired wind speed can be obtained.

[0046] Furthermore, an effect similar to that described above may be obtained by thinning the thickness of at least a part of the dielectric 10 without completely exposing at least a part of the intermediate electrode 40 (see FIG. 9).

[0047] Seventh Embodiment As shown in FIG. 9, the plasma actuator 7 of this embodiment has the same configuration as the plasma actuator 1 of the first embodiment, except that the dielectric 10 has inclined surfaces 10a, 10b on both the front surface 10A and the back surface 10B, where the thickness gradually decreases, and these inclined surfaces 10a, 10b are provided in the in-plane direction (toward the right in the figure) in which the intermediate electrode 40 is arranged offset.

[0048] However, the present invention is not limited to this arrangement or structure, and for example, although not shown, the dielectric 10 may have inclined surfaces 10a, 10b on either the front surface 10A or the back surface 10B, the thickness of which gradually decreases, and these inclined surfaces 10a, 10b may be provided in the in-plane direction in which the intermediate electrodes 40 are shifted. Furthermore, although not shown, the dielectric 10 may have a step structure on at least one side of the front surface 10A or the back surface 10B, the thickness of which gradually decreases, and this step structure may be provided in the in-plane direction in which the intermediate electrodes 40 are shifted.

[0049] Next, the advantages of this embodiment will be described. According to the plasma actuator 7 of the present embodiment, the induced flows F converge at the end 10D side of the dielectric 10 due to the inclined surfaces 10a and 10b provided on both the front surface 10A and the back surface 10B of the dielectric 10, and therefore in addition to the advantages of the first embodiment, it is possible to generate an even stronger induced flow F than the plasma actuator 1 of the first embodiment. Furthermore, from the viewpoint of making it less likely to obstruct the flow of the induced flow F, providing the inclined surfaces described above is preferable to providing the step structure described above.

[0050] In addition, when an even stronger induced flow F is generated on the front surface 10A side of the dielectric 10, the above-mentioned inclined surface 10b can be provided only on the back surface 10B side of the dielectric 10 to merge the induced flows F. On the other hand, when an even stronger induced flow F is generated on the back surface 10B side of the dielectric 10, the above-mentioned inclined surface 10a can be provided only on the front surface 10A side of the dielectric 10 to merge the induced flows F. With the above-mentioned configuration, a desired wind speed can be obtained.

[0051] Eighth Embodiment As shown in FIG. 10, the plasma actuator 8 of this embodiment has the same configuration as the plasma actuator 1 of the first embodiment, except that the dielectric 10 has inclined surfaces 10a, 10b on both the front surface 10A and the back surface 10B, with the thickness gradually increasing, and these inclined surfaces 10a, 10b are provided in the in-plane direction (toward the right in the figure) in which the intermediate electrode 40 is arranged offset.

[0052] However, the present invention is not limited to this arrangement or structure, and for example, although not shown, the dielectric 10 may have inclined surfaces 10a, 10b on either the front surface 10A or the back surface 10B, the thickness of which gradually increases, and these inclined surfaces 10a, 10b may be provided in the in-plane direction in which the intermediate electrodes 40 are shifted. Furthermore, although not shown, the dielectric 10 may have a step structure on at least one side of the front surface 10A or the back surface 10B, the thickness of which gradually increases, and this step structure may be provided in the in-plane direction in which the intermediate electrodes 40 are shifted.

[0053] Next, the advantages of this embodiment will be described. According to the plasma actuator 8 of this embodiment, the above-mentioned inclined surfaces 10a, 10b are provided on both the front surface 10A and the back surface 10B of the dielectric 10, and therefore, in addition to the advantages of the first embodiment, the induced flow F can be made to flow in the thickness direction (the vertical direction in the drawing) of the dielectric 10. Furthermore, from the viewpoint of making it difficult to obstruct the flow of the induced flow F, providing the above-mentioned inclined surfaces is preferable to providing the above-mentioned step structure.

[0054] When the induced flow F is made to flow upward on the front surface 10A side of the dielectric 10, the above-mentioned inclined surface 10a may be provided on the front surface 10A side of the dielectric 10, and the above-mentioned inclined surface 10b may not be provided on the back surface 10B side of the dielectric 10. On the other hand, when the induced flow F is made to flow downward on the back surface 10B side of the dielectric 10, the above-mentioned inclined surface 10b may be provided on the back surface 10B side of the dielectric 10, and the above-mentioned inclined surface 10a may not be provided on the front surface 10A side of the dielectric 10. With the above-mentioned configuration, it is possible to obtain the induced flow F in a desired direction.

[0055] Although the present invention has been described above using a few embodiments, the present invention is not limited to these, and various modifications are possible within the scope of the present invention. For example, the components described above are not limited to the configurations shown in each embodiment, and it is possible to change the specifications and arrangement of the front electrode, back electrode, intermediate electrode, and dielectric, or to apply the components of each embodiment to other embodiments. [Explanation of symbols]

[0056] 1,2,3,4,5,5A,5B,6,7,8 Plasma Actuator 10 Dielectrics 10A 1st side (front) 10a Slope 10B 2nd side (back side) 10b Slope 10C Notch 10D end 11 First dielectric 13 Second Dielectric 20 1st electrode (surface electrode) 30 2nd electrode (back electrode) 40 Third electrode (intermediate electrode) 50 integrated electrode 60,61,62 Power supply 70, 71, 72, 73, 74 Wiring F induced flow P plasma V1 Potential of the first electrode (surface electrode) V2 Potential of the second electrode (back electrode) V3: Potential of the third electrode (intermediate electrode)

Claims

1. A plasma actuator including a dielectric, a first electrode provided on a first surface of the dielectric, a second electrode provided on a second surface of the dielectric facing the first surface, and a power supply that generates a predetermined AC voltage, Further comprising a third electrode disposed in the dielectric; the third electrode is arranged to be shifted in any one of in-plane directions of the dielectric with respect to the first electrode and the second electrode, the power supply applies a voltage between the first electrode and the third electrode and also applies a voltage between the second electrode and the third electrode; the first electrode and the second electrode have at least a state in which the polarity of the voltage applied thereto is the same; A plasma actuator, characterized in that a potential difference between the first electrode and the third electrode is different from a potential difference between the second electrode and the third electrode.

2. A plasma actuator including a dielectric, a first electrode provided on a first surface of the dielectric, a second electrode provided on a second surface of the dielectric facing the first surface, and a power supply that generates a predetermined AC voltage, Further comprising a third electrode disposed in the dielectric; the third electrode is arranged to be shifted in any one of in-plane directions of the dielectric with respect to the first electrode and the second electrode, the power supply applies a voltage between the first electrode and the third electrode and also applies a voltage between the second electrode and the third electrode; the first electrode and the second electrode have at least a state in which the polarity of the voltage applied thereto is the same; A plasma actuator, wherein the shortest distance between the third electrode and the first electrode is different from the shortest distance between the third electrode and the second electrode.

3. A plasma actuator including a dielectric, a first electrode provided on a first surface of the dielectric, a second electrode provided on a second surface of the dielectric facing the first surface, and a power supply that generates a predetermined AC voltage, Further comprising a third electrode disposed in the dielectric; the third electrode is arranged to be shifted in any one of in-plane directions of the dielectric with respect to the first electrode and the second electrode, the power supply applies a voltage between the first electrode and the third electrode and also applies a voltage between the second electrode and the third electrode; the first electrode and the second electrode have at least a state in which the polarity of the voltage applied thereto is the same; A plasma actuator, characterized in that at least a portion of the third electrode is exposed on at least one of the first surface and the second surface of the dielectric.

4. 4. The plasma actuator according to claim 1, wherein the first electrode and the second electrode have the same potential.

5. A plasma actuator including a dielectric, a first electrode provided on a first surface of the dielectric, a second electrode provided on a second surface of the dielectric facing the first surface, and a power supply that generates a predetermined AC voltage, Further comprising a third electrode disposed in the dielectric; the third electrode is arranged to be shifted in any one of in-plane directions of the dielectric with respect to the first electrode and the second electrode, the power supply applies a voltage between the first electrode and the third electrode and also applies a voltage between the second electrode and the third electrode; the first electrode and the second electrode have at least a state in which the polarity of the voltage applied thereto is the same; A plasma actuator, characterized in that the first electrode and the second electrode are united to form an integrated electrode that penetrates the dielectric.

6. 6. The plasma actuator according to claim 1, wherein the dielectric has an inclined surface on at least one of the first surface and the second surface, the thickness of which gradually decreases, and the inclined surface is provided in an in-plane direction in which the third electrode is arranged offset.

7. 6. The plasma actuator according to claim 1, wherein the dielectric has an inclined surface on at least one of the first surface and the second surface, the thickness of which gradually increases, and the inclined surface is provided in an in-plane direction in which the third electrode is arranged in a shifted manner.

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