阅读说明：本技术 气流剥离检测方法和系统、气流剥离位置检测方法和系统 (Airflow stripping detection method and system and airflow stripping position detection method and system ) 是由 加藤宏基 于 2020-08-24 设计创作，主要内容包括：本发明涉及气流剥离检测方法和系统、气流剥离位置检测方法和系统。提供在物体上不重新安装传感器或不使用原有的传感器就能够检测气流是否从物体表面剥离等的气流剥离检测方法及气流剥离位置检测方法等。在气流剥离检测方法中,在向配置于物体的表面部分的等离子促动器施加了规定电压值的交流电压的状态下测量的等离子促动器的消耗电力(p)或电流值(i)相对于时间的变化率的绝对值成为规定值以上的情况下,检测到在物体表面上流动的气流(A)从物体表面剥离。另外,在气流剥离位置检测方法中,使用上述气流剥离检测方法,在检测到在物体表面上流动的气流从物体表面剥离时成为检测对象的等离子促动器的位置检测到气流从物体表面剥离。(The invention relates to an airflow stripping detection method and system and an airflow stripping position detection method and system. Provided are an airflow peeling detection method and an airflow peeling position detection method, etc., by which it is possible to detect whether or not an airflow has peeled from the surface of an object without newly attaching a sensor to the object or without using an existing sensor. In the airflow separation detection method, when the absolute value of the rate of change of the power consumption (p) or the current value (i) with respect to time of a plasma actuator, which is measured in a state in which an alternating voltage having a predetermined voltage value is applied to the plasma actuator disposed on the surface portion of an object, is equal to or greater than a predetermined value, separation of an airflow (A) flowing on the surface of the object from the surface of the object is detected. In the airflow separation position detection method, the airflow separation detection method is used to detect that the airflow is separated from the surface of the object at a position of the plasma actuator that is a detection target when the airflow flowing over the surface of the object is detected to be separated from the surface of the object.)

1. A method for detecting the separation of an air flow, wherein the separation of an air flow flowing on the surface of an object from the surface of the object is detected when the absolute value of the rate of change of the power consumption or current value of a plasma actuator with respect to time, which is measured in a state where an AC voltage having a predetermined voltage value is applied to the plasma actuator disposed on the surface of the object, is equal to or greater than a predetermined value.

2. A method for detecting peeling of an air flow, wherein, when an absolute value of a rate of change with respect to time of a power consumption or a current value of one or more first plasma actuators among a plurality of plasma actuators at a certain time, among power consumption or current values of the respective plasma actuators measured in a state where an alternating voltage of a predetermined voltage value is applied to each of the plurality of plasma actuators arranged on a surface portion of an object in a direction in which the air flow flows on the surface of the object, is larger than an absolute value of a rate of change with respect to time of a power consumption or a current value of another plasma actuator different from the first plasma actuator at the certain time, it is detected that the air flow flowing on the surface of the object has peeled off from the surface of the object.

3. The airflow peel detection method of claim 1, wherein the object is a wing of an aircraft.

4. The airflow peel detection method of claim 2, wherein the object is a wing of an aircraft.

5. A method for detecting a peeling position of an air flow, wherein peeling of the air flow from a surface of the object is detected at a position of the plasma actuator to be a detection target when peeling of the air flow flowing on the surface of the object from the surface of the object is detected, by using the method for detecting peeling of an air flow according to any one of claims 1 to 4.

6. A stripping detection system for an airflow comprising:

a plasma actuator disposed on a surface portion of the object; and

a detection device that detects whether the airflow flowing on the surface of the object is peeled off from the surface of the object,

wherein the detection device detects that the airflow flowing on the surface of the object has peeled off from the surface of the object when an absolute value of a rate of change with respect to time of power consumption or a current value of the plasma actuator measured in a state where an alternating voltage of a predetermined voltage value is applied to the plasma actuator becomes a predetermined value or more.

7. A stripping detection system for an airflow comprising:

a plurality of plasma actuators arranged on a surface portion of an object along a direction in which an air flow flows on the surface of the object; and

a detection device that detects whether the airflow flowing on the surface of the object is peeled off from the surface of the object,

wherein the detection device detects that the gas flow flowing on the surface of the object has peeled off from the surface of the object when an absolute value of a rate of change with respect to time of the power consumption or current value of one or more first plasma actuators at a certain time is larger than or equal to a predetermined value than an absolute value of a rate of change with respect to time of the power consumption or current value of the plasma actuators other than the first plasma actuators at the certain time, among power consumption or current values of the respective plasma actuators measured in a state in which an alternating voltage of a predetermined voltage value is applied to each of the plurality of plasma actuators arranged on the surface portion of the object in a direction in which the gas flow flows on the surface of the object.

8. The stripping detection system for gas flows according to claim 6,

the object is a wing of an aircraft.

9. The stripping detection system for gas flows according to claim 7,

the object is a wing of an aircraft.

10. A peeling position detecting system for an air flow, comprising the peeling position detecting system for an air flow according to any one of claims 6 to 9,

the detection device of the peeling detection system of the air current detects peeling of the air current from the surface of the object at the position of the plasma actuator that is a detection object when detecting peeling of the air current flowing on the surface of the object from the surface of the object.

Technical Field

The present invention relates to a method for detecting detachment of an air flow, a method for detecting a position of detachment of an air flow, a system for detecting detachment of an air flow, and a system for detecting a position of detachment of an air flow, each using a plasma actuator.

Background

The plasma actuator is a member that generates plasma discharge by applying an alternating voltage between a pair of electrodes disposed so as to be displaced relative to each other with a dielectric interposed therebetween, and can form an air flow along the plasma discharge direction by driving the plasma actuator.

In recent years, the following techniques have been developed: in a case where a plasma actuator is attached to a blade of an aircraft such as an airplane or a helicopter, a blade of a wind turbine generator, or the like, and an airflow flowing on a surface of the blade is peeled off from the surface of the blade, or a case where peeling is predicted, or the like, the plasma actuator disposed on a surface portion of the blade is driven to return the airflow from a state of being peeled off from the surface of the blade to a state of being attached to the surface of the blade, or to maintain the airflow in a state of being attached to the surface of the blade (for example, refer to patent documents 1 to 3).

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2012-225296

Patent document 2: japanese patent laid-open publication No. 2019-84897

Patent document 3: japanese patent laid-open publication No. 2019-114505

Disclosure of Invention

Technical problem to be solved by the invention

However, conventionally, in order to determine whether or not the airflow is detached from the surface of the blade, measurement values of a flow velocity sensor, a pressure sensor, and the like, which are newly attached to the blade, a flow velocity sensor, a pressure sensor, and the like, which are previously attached to an aircraft, and the like, are used.

However, there are problems that aerodynamic force is affected by the mounted sensor when the sensor is remounted, or the sensor is not necessarily provided at an appropriate position to detect peeling of the airflow when the original sensor is used.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a peeling detection method of an air flow, a peeling position detection method of an air flow, a peeling detection system of an air flow, and a peeling position detection system of an air flow, which can detect whether an air flow peels from a surface of an object without newly attaching a sensor to the object or without using an original sensor.

Means for solving the problems

In order to solve the above problem, a first aspect of the present invention provides a method for detecting separation of an air flow from a surface of an object, the method being characterized in that separation of the air flow flowing on the surface of the object from the surface of the object is detected when an absolute value of a rate of change with respect to time of a power consumption or a current value of a plasma actuator measured in a state where an ac voltage having a predetermined voltage value is applied to the plasma actuator disposed on the surface of the object becomes a predetermined value or more.

A second aspect of the present invention provides a method for detecting peeling of an air flow, wherein peeling of the air flow flowing on a surface of an object from the surface of the object is detected when an absolute value of a rate of change with respect to time of a power consumption or a current value of one or more plasma actuators at a certain time is equal to or greater than a predetermined value, among power consumption or current values of the plasma actuators measured in a state in which an ac voltage having a predetermined voltage value is applied to each of the plasma actuators arranged on the surface of the object in a direction in which the air flow flows on the surface of the object.

An invention of a third aspect is the peeling detection method of an airflow of the first or second aspect, wherein the object is a wing panel of an aircraft.

A fourth aspect of the present invention provides a method for detecting a peeling position of an air flow, wherein peeling of the air flow from a surface of the object is detected at a position of the plasma actuator that is a detection target when peeling of the air flow flowing on the surface of the object from the surface of the object is detected, using the method for detecting peeling of an air flow of any one of the first to third aspects.

The invention of a fifth aspect provides an airflow separation detection system, comprising: a plasma actuator disposed on a surface portion of the object; and a detection device that detects whether or not the airflow flowing over the surface of the object peels off from the surface of the object, wherein the detection device detects that the airflow flowing over the surface of the object peels off from the surface of the object when an absolute value of a rate of change with respect to time of power consumption or a current value of the plasma actuator measured in a state where an alternating voltage of a predetermined voltage value is applied to the plasma actuator becomes a predetermined value or more.

The present invention in a sixth aspect provides an airflow separation detection system, comprising: a plurality of plasma actuators arranged on a surface portion of an object along a direction in which an air flow flows on the surface of the object; a detection device that detects whether the airflow flowing on the surface of the object is peeled off from the surface of the object, wherein the detection device is configured to detect a change rate of the power consumption or the current value of one or more of the plasma actuators with respect to time at a certain time among the power consumption or the current value of each of the plasma actuators measured in a state where an alternating voltage having a predetermined voltage value is applied to each of the plurality of plasma actuators arranged on the surface portion of the object in the direction in which the air flow flows on the surface of the object, and when an absolute value of a change rate of the power consumption or the current value with respect to time of one or more of the plasma actuators at the certain time is greater than or equal to a predetermined value, detecting peeling of the airflow flowing over the surface of the object from the surface of the object.

An invention of a seventh aspect is the peeling detection system of the fifth or sixth aspect, characterized in that the object is a wing of an aircraft.

An eighth aspect of the present invention provides an airflow detachment position detection system including the airflow detachment detection system according to any one of the fifth to seventh aspects, wherein the detection device of the airflow detachment detection system detects detachment of the airflow from the surface of the object at a position of the plasma actuator that is a detection target when detachment of the airflow flowing on the surface of the object from the surface of the object is detected.

Effects of the invention

According to the present invention, in the method for detecting peeling of an air flow, the method for detecting peeling position of an air flow, the system for detecting peeling of an air flow, and the system for detecting peeling position of an air flow, it is possible to detect whether or not an air flow is peeled from the surface of an object or the position where the air flow is peeled by using a plasma actuator without newly attaching a sensor to the object or without using an original sensor.

Drawings

Fig. 1 is a schematic cross-sectional view showing the structure of a plasma actuator.

Fig. 2(a) is a diagram showing a state in which the airflow is peeled off from the surface of the fin, and fig. 2(B) is a diagram showing a state in which the airflow returns to adhere to the surface of the fin.

Fig. 3 a is a diagram showing a waveform of a constant ac voltage, and fig. 3B is a diagram showing an ac voltage of a burst waveform (バースト waveform).

Fig. 4 is a diagram showing a configuration of the airflow separation detection system according to the first embodiment.

Fig. 5 is a diagram showing a state in which the power consumption of the plasma actuator is substantially constant and a state in which the power consumption fluctuates sharply.

Fig. 6 is a diagram showing a state in which the gas flow is peeled off from the surface of the object at the position of the plasma actuator.

Fig. 7 is a diagram showing an example in which a plurality of plasma actuators are arranged side by side on the surface portion of the object along the direction in which the gas flow flows on the surface of the object.

Fig. 8 is a diagram showing a configuration of a separation detection system for airflow according to a second embodiment.

Fig. 9 is a diagram showing a time lapse of power consumption of each plasma actuator when the gas flow is displaced at the position of 1 plasma actuator among the plurality of plasma actuators.

Fig. 10 is a diagram showing a time lapse of power consumption of each plasma actuator when the gas flow is displaced at the position of 2 plasma actuators out of the plurality of plasma actuators.

Description of the symbols

1 plasma actuator

7. 8 detection device

10. 20 airflow peeling detection system and airflow peeling position detection system

100 object, vane

101 aircraft

A gas flow

i current value

time t0, time t1

p consumption power

Vm maximum amplitude (specified voltage value)

Detailed Description

Embodiments of a method for detecting peeling of an air flow, a method for detecting peeling position of an air flow, a system for detecting peeling of an air flow, and a system for detecting peeling position of an air flow according to the present invention will be described below with reference to the accompanying drawings.

In the present invention, the separation detection and the separation position detection of the airflow flowing on the surface of the blade are performed, but in this case, the separation and the separation position of the airflow from the surface of the blade are detected based on the power consumption and the current value by using the plasma actuator disposed on the surface portion of the blade as described below without newly attaching a flow velocity sensor, a pressure sensor, or the like of the airflow to the blade or using a flow velocity sensor, a pressure sensor, or the like attached to an aircraft or the like in advance.

Further, although the following description will be made of a case where the plasma actuator is disposed on the surface portion of the blade of the aircraft, the airflow detachment detection method, the airflow detachment position detection system, and the airflow detachment position detection system according to the present invention can be applied to, for example, the detachment and the detachment position detection of the airflow flowing on the surface of the blade of the wind turbine generator, and can also be applied to the detachment and the detachment position detection of the airflow flowing on the surface of an object other than the blade.

In the following, a case will be described in which the plasma actuator is disposed on the surface portion of the blade in order to drive the plasma actuator in a case where the airflow flowing on the surface of the blade is peeled off from the surface of the blade or in a case where peeling is predicted, and to return the airflow from a state of being peeled off from the surface of the blade to a state of being attached to the surface of the blade or to maintain the state of being attached to the surface of the blade.

[ plasma actuator ]

Hereinafter, the structure, control method, and the like of the plasma actuator will be briefly described. Fig. 1 is a schematic cross-sectional view showing the structure of a plasma actuator.

The plasma actuator 1 includes: a first electrode 2, a second electrode 3, a dielectric 4, an AC power supply 5, and a control unit 6 for controlling the AC power supply 5. The first electrode 2 and the second electrode 3 are disposed with the dielectric 4 interposed therebetween, and are disposed with a relative displacement in the extending direction of the dielectric 4.

In addition, the second electrode 3 is grounded. Then, an ac voltage is applied between the first electrode 2 and the second electrode 3 by the ac power supply 5.

Then, when the ac power supply 5 is operated by the control unit 6 in this state and a high-voltage ac voltage is applied between the first electrode 2 and the second electrode 3 at a high frequency, plasma P composed of electrons and positive ions is generated on the surface of the dielectric 4 on the side surface of the first electrode 2 at a position corresponding to the second electrode 3 so as to be ejected from the first electrode 2. Then, as the plasma P is ejected, an air flow a (see an arrow a in the drawing) of air flowing on the surface of the dielectric 4 in the ejection direction of the plasma P is generated toward the surface of the dielectric 4.

That is, by driving the plasma actuator 1 (by applying a high-frequency ac voltage between the first electrode 2 and the second electrode 3), plasma P is generated on the side surface of the first electrode 2, and the air flow a of air flowing on the surface of the dielectric 4 can be generated by the ejection of plasma.

In this way, by using the air flow a that can generate air on the surface of the fin by the plasma actuator 1, for example, as described above, the air flow can be returned to a state of adhering to the surface of the fin by driving the plasma actuator in a case where the air flow flowing on the surface of the fin is peeled off from the surface of the fin.

That is, when the airflow a flowing on the surface of the fin 100 is peeled off from the surface of the fin 100 as shown in fig. 2 a, the plasma actuator 1 is driven on the upstream side of the position where the airflow a is peeled off (the upstream side in the direction in which the airflow a flows) to generate the plasma P on the side surface on the downstream side of the first electrode 2 and generate the airflow a of air as shown in fig. 2B, the airflow a returns to the state of adhering to the surface of the fin 100.

In this way, using the plasma actuator 1, the airflow a flowing over the surface of the vane 100 can be controlled.

Further, as the alternating voltage V applied from the alternating current power supply 5 to between the first electrode 2 and the second electrode 3, for example, a constant alternating voltage as shown in fig. 3(a) can be applied to continuously generate the plasma P, but it has been found in the study of the present inventors that when the alternating voltage V is applied with a burst waveform alternating voltage as shown in fig. 3(B), the airflow a can be appropriately attached to the surface of the fin 100 when the flow rate of the airflow a is slow, particularly when the flow rate of the airflow a is fast.

In this case, the burst waveform is a waveform in which a period (a period in which the amplitude is not 0) in which the amplitude (maximum amplitude Vm) is positive and a period in which the amplitude is 0 are repeated at a fixed cycle (burst cycle) T, as shown in fig. 3B. The plasma P is generated during the positive amplitude, but is not generated during the 0 amplitude.

Further, in the studies by the present inventors, it was found that the effect of causing the airflow a by the plasma actuator 1 to adhere to the surface of the fin 100 is dominantly affected by the burst frequency f (═ 1/T).

That is, by appropriately adjusting the burst frequency f (or the burst period T), the plasma actuator 1 is driven in a case where the airflow a flowing on the surface of the fin 100 peels off from the surface of the fin 100, a case where peeling is predicted, or the like, and thereby the airflow a can be effectively returned from a state of being peeled off from the surface of the fin 100 to a state of being adhered to the surface of the fin 100, or the airflow a can be effectively maintained in a state of being adhered to the surface of the fin 100.

The control unit 6 can adjust a waveform or a burst period T (burst frequency f) of the ac voltage V applied from the ac power supply 5 between the first electrode 2 and the second electrode 3, a period Ton in which the amplitude is positive (including a case where Ton is T (that is, a case of a constant ac voltage)), and the like. The maximum amplitude Vm of the ac voltage V may vary with time without being fixed with time.

[ method and System for detecting peeling position of air flow ]

Next, an embodiment of a gas flow separation detection system and a gas flow separation position detection system according to the present invention using the plasma actuator 1 will be described.

Note that the following description of the airflow separation detection system and the airflow separation position detection system will also be made for the airflow separation detection method and the airflow separation position detection method of the present embodiment, but the airflow separation detection method and the airflow separation position detection method are not limited to the case where the detection device 7 described later detects separation or the like of the airflow a. In the following, the detection device 7 and the control unit 6 of the ac power supply 5 are described as separate devices, but they may be integrally configured.

In the following, the above-described fin 100 will be described as a general object 100.

[ first embodiment ]

[ method and System for detecting peeling of air flow ]

Fig. 4 is a diagram showing a configuration of the airflow separation detection system according to the first embodiment.

In fig. 4, the first electrode 2 of the plasma actuator 1 is shown to be relatively thick for easy observation, but actually, the first electrode 2 is formed to be very thin, such as a film shape, so as not to affect the gas flow a flowing on the surface of the object 100.

The airflow separation detection system 10 of the present embodiment includes: the plasma actuator 1 disposed on the surface portion of the object 100, and the detection device 7 connected to the control unit 6 of the ac power supply 5. The detection device 7 may be directly connected to the ac power supply 5 without the control unit 6.

The detection device 7 includes a computer such as a memory for storing a processor program and causing the processor to execute the program, and a microcomputer connected to the one or more plasma actuators and configured to determine whether or not the gas flow is separated based on the sensor value. It is detected whether the airflow a flowing on the surface of the object 100 is peeled off from the surface of the object 100. In the following, for the sake of simplicity, a case where a constant ac voltage (see fig. 3 a) having a temporally constant maximum amplitude Vm is applied to the plasma actuator 1 is described, but a case where an ac voltage having another waveform such as a burst waveform ac voltage (see fig. 3B) is applied is also similarly described.

When the power consumption p of the ac power supply 5 of the plasma actuator 1 disposed on the surface portion of the object 100 is measured, as shown in fig. 4, if the airflow a flowing on the surface of the object 100 adheres to the surface of the object 100 at the position of the plasma actuator 1, the power consumption p is substantially constant as shown by the portion indicated by α in fig. 5 if the flow speed or the like of the airflow a does not change.

However, as shown in fig. 6, when the air current a is peeled off from the surface of the object 100 at the position of the plasma actuator 1, the power consumption p of the plasma actuator 1 may fluctuate rapidly as shown by a portion denoted by β in fig. 5.

The reason for this phenomenon is not always clear, but can be considered as follows.

That is, as shown in fig. 4, when the airflow a adheres to the surface of the object 100, the airflow a flows stably and the flow rate of the airflow a becomes constant. Further, for example, when the speed of the aircraft changes, the speed changes relatively slowly, not instantaneously largely, and therefore the flow rate of the airflow a on the surface of the blade (object 100) of the aircraft also changes relatively slowly.

On the other hand, as shown in fig. 6, when the airflow a peels off from the surface of the object 100, the airflow a may be disturbed, for example, by a part of the airflow a flowing in the reverse direction. Therefore, the airflow a becomes unstable, and the flow rate of the airflow a changes relatively sharply.

As described above, since the high-frequency and high-voltage ac voltage is applied to the plasma actuator 1, the molecules in the gas flow a are ionized in the vicinity of the plasma actuator 1 by the high-voltage ac voltage applied to the plasma actuator 1.

Moreover, when the molecules in the air flow a are ionized, the current value that is apparent (on the view かけ) in the plasma actuator 1 becomes large, and the power consumption p in the plasma actuator 1 becomes large.

In this state, as described above, when the airflow a adheres to the surface of the object 100, the airflow a flows stably, and the flow rate of the airflow a is also stable, so that the amount of ionized molecules becomes a fixed amount, and even if it changes, it changes slowly. Therefore, when the gas flow a adheres to the surface of the object 100 at the position of the plasma actuator 1, the measured power consumption p of the plasma actuator 1 is substantially constant or changes slowly.

In contrast, when the airflow a peels off the surface of the object 100 at the position of the plasma actuator 1, the flow rate of the airflow a changes relatively rapidly as described above, and therefore the amount of ionized molecules changes relatively rapidly by the high-voltage ac voltage applied to the plasma actuator 1. Therefore, it can be considered that the measured power consumption p of the plasma actuator 1 changes relatively rapidly.

Therefore, by utilizing the above phenomenon, in the present embodiment, when the absolute value of the rate of change with respect to time of the power consumption p of the plasma actuator 1 measured in a state where the ac voltage V of a predetermined voltage value (for example, the maximum amplitude Vm) is applied to the plasma actuator 1 disposed on the surface portion of the object 100 becomes a predetermined value or more, it is configured to detect that the airflow a flowing on the surface of the object 100 has peeled off from the surface of the object 100.

Instead of the power consumption p of the plasma actuator 1, a current value i (including the contribution amount due to the ionized molecules) of the plasma actuator 1 may be measured. The airflow separation detection system 10 is configured such that the detection device 7 performs this process.

As the predetermined value, a value that can divide the state where the air flow a adheres to the surface of the object 100 and the state where the air flow a peels off from the surface of the object 100 is appropriately set by experiments, simulations, or the like in advance.

As described above, according to the method for detecting peeling of an air current and the system 10 for detecting peeling of an air current of the present embodiment, it is possible to detect whether or not the air current a flowing on the surface of the object 100 is peeled from the surface of the object 100 only by monitoring the rate of change of the power consumption p or the current value i in the plasma actuator 1 with respect to time (the absolute value of the rate of change with respect to time).

Therefore, according to the airflow peeling detection method and the airflow peeling detection system 10 of the present embodiment, it is possible to accurately detect whether the airflow a peels from the surface of the object 100 without newly attaching a sensor such as a flow rate sensor or a pressure sensor to the object 100 or using an original sensor.

[ method and System for detecting peeling position of airflow ]

In the above-described airflow detachment detection method and airflow detachment detection system 10, as described above, when the absolute value of the rate of change of the power consumption p of the plasma actuator 1 with respect to time is equal to or greater than the predetermined value, detachment of the airflow a from the surface of the object 100 can be detected at least at the position of the surface of the object 100 where the plasma actuator 1 (that is, the plasma actuator 1 that is the detection target when the airflow a is detected by the airflow detachment detection method and airflow detachment detection system 10) is disposed.

Therefore, the airflow separation position detection (airflow separation position detection method) can be performed using the airflow separation detection method of the present embodiment. The airflow separation detection system 10 according to the present embodiment also functions as an airflow separation position detection system.

Further, with this structure, it is possible to accurately detect the position where the air flow a peels off from the surface of the object 100 using only the plasma actuator 1 without using other sensors.

The detection of the peeling position of the air flow a by the air flow peeling position detecting system 10 may be performed by the detecting device 7, or may be performed by a device different from the detecting device 7.

[ second embodiment ]

[ method and System for detecting peeling of air flow ]

In the first embodiment, the case where the separation detection of the airflow a is performed using 1 plasma actuator 1 has been described, but the separation detection of the airflow a may be performed using a plurality of plasma actuators 1.

In this case, as shown in fig. 7, the plurality of plasma actuators 1 are arranged in parallel on the surface portion of the object 100 (for example, the blade 100 of the aircraft 101) in the direction in which the airflow a flows on the surface of the object 100. As shown in fig. 8, each plasma actuator 1 is configured similarly to the first embodiment, but the detection device 8 of the airflow separation position detection system 20 according to the present embodiment is connected to the control unit 6 of the ac power supply 5 of each plasma actuator 1.

In the present embodiment, the detection device 8 may be directly connected to the ac power supply 5 of each plasma actuator 1.

In addition, although fig. 7 and 8 show a case where 3 plasma actuators 1(1A, 1B, 1C) are arranged along the direction in which the airflow a flows on the surface of the object 100, and a case where such a configuration is described below, the number of plasma actuators 1 arranged along the direction in which the airflow a flows on the surface of the object 100 may be different from 3.

In the present embodiment, similarly to the first embodiment, it can be configured such that when the absolute value of the rate of change with respect to time of the power consumption p or the current value i of any plasma actuator 1 measured in a state where the ac voltage V of a predetermined voltage value (for example, the above-described maximum amplitude Vm) is applied to each plasma actuator 1 becomes a predetermined value or more, it is detected that the airflow a flowing on the surface of the object 100 has peeled off from the surface of the object 100.

In the case of such a configuration, the detection device 8 is configured to individually monitor the power consumption p or the current value i of each plasma actuator 1.

On the other hand, the method for detecting separation of an air flow and the system 20 for detecting separation of an air flow according to the present embodiment can be configured as follows by including a plurality of plasma actuators 1.

That is, as described above, it is possible to configure that, in the power consumption p or the current value i of each plasma actuator 1 measured in a state where the ac voltage a having the predetermined voltage value is applied to each of the plurality of plasma actuators 1 arranged on the surface portion of the object 100 in the direction in which the airflow a flows on the surface of the object 100, when the absolute value of the rate of change with respect to time of the power consumption p or the current value i of one or a plurality of plasma actuators 1 at a certain time is greater than or equal to the predetermined value compared with the absolute value of the rate of change with respect to time of the power consumption p or the current value i of the other plasma actuators 1 at that time, it is detected that the airflow a flowing on the surface of the object 100 has peeled off from the surface of the object 100.

The following is a detailed description. In addition, although the case of measuring the power consumption p of each plasma actuator 1 will be described below, the current value i of each plasma actuator 1 may be measured.

As in the case of the first embodiment (see fig. 5), when the airflow a flowing on the surface of the object 100 adheres to the surface of the object 100 at each position where the plasma actuators 1A, 1B, and 1C are disposed, the power consumptions pa, pb, and pc of the plasma actuators 1A, 1B, and 1C are substantially constant or change gradually even if they change, as shown by the portion indicated by γ in fig. 9.

In this state, for example, as shown in fig. 8, when the air current a is peeled off from the surface of the object 100 at the position of the plasma actuator 1C, the power consumption pc of the plasma actuator 1C may fluctuate rapidly as shown by the portion indicated by δ in fig. 9.

In contrast, as shown in fig. 8, when the airflow a is in a state of adhering to the surface of the object 100 at each position of the other plasma actuators 1A and 1B, the power consumptions pa and pb of the plasma actuators 1A and 1B are in a fixed state or a state of gradually changing even if they change.

Therefore, in this case, when the absolute value of the rate of change with respect to time of the power consumption pc of the plasma actuator 1C at a certain time (see, for example, t0 in fig. 9) is compared with the absolute values of the rates of change with respect to time of the power consumption pa and pb of the other plasma actuators 1A and 1B at the same time, the absolute value of the rate of change with respect to time of the power consumption pc of the plasma actuator 1C is significantly larger than the absolute values of the rates of change with respect to time of the power consumption pa and pb of the respective plasma actuators 1A and 1B.

Therefore, as described above, when the absolute value of the rate of change with respect to time of the power consumption pc of the plasma actuator 1C at a certain time is greater than or equal to the absolute value of the rate of change with respect to time of the power consumption pa and pb of the other plasma actuators 1A and 1B at the same time, it is detected that the airflow a flowing on the surface of the object 100 has peeled off from the surface of the object 100, and thus the peeling of the airflow a can be reliably detected.

Fig. 8 shows a case where the air current a is separated from the surface of the object 100 only at the position of the plasma actuator 1C, but when the air current a is simultaneously separated from the surface of the object 100 at both positions of the plasma actuators 1B and 1C, for example, as shown in fig. 10, the power consumption pa of the other plasma actuator 1A is substantially constant or is maintained in a state of slowly changing, but the power consumption pb and pc of the plasma actuators 1B and 1C are in a state of rapidly changing.

Therefore, by comparing the absolute values of the change rates with time of the power consumptions pb and pc of the plasma actuators 1B and 1C at a certain time (see, for example, t1 in fig. 10) with the absolute value of the change rate with time of the power consumption pa of the other plasma actuator 1A at the same time, it is possible to reliably detect the separation of the air flow a.

As described above, according to the method for detecting separation of an air flow and the system 20 for detecting separation of an air flow of the present embodiment, it is possible to detect whether or not the air flow a flowing on the surface of the object 100 is separated from the surface of the object 100 by monitoring only the rate of change of the power consumption p or the current value i with respect to time (the absolute value of the rate of change with respect to time) in each plasma actuator 1.

Therefore, according to the airflow peeling detection method and the airflow peeling detection system 20 of the present embodiment, it is possible to accurately detect whether the airflow a peels from the surface of the object 100 without newly attaching a sensor such as a flow rate sensor or a pressure sensor to the object 100 or using an original sensor.

[ method and System for detecting peeling position of airflow ]

As is clear from the above description, if the method for detecting peeling of an air flow and the system for detecting peeling of an air flow 20 according to the present embodiment are used, it is possible to detect whether or not the air flow a peels from the surface of the object 100 at any position of the plasma actuator 1 (the position of the plasma actuator 1C in the example of fig. 8).

That is, when the absolute value of the rate of change with respect to time of the power consumption p or the current value i of the plasma actuator 1 at a certain time is greater than or equal to the absolute value of the rate of change with respect to time of the power consumption p or the current value i of the other plasma actuator 1 at that time, it is possible to detect that the gas flow a has peeled from the surface of the object 100 at the position of the surface of the object 100 where the target plasma actuator 1 (the target plasma actuator 1 is the plasma actuator 1 having a large absolute value that becomes the detection target when the peeling detection method using the gas flow and the peeling detection system 20 using the gas flow detect that the gas flow a has peeled from the surface of the object 100) is arranged.

Therefore, the airflow separation position detection method (airflow separation position detection method) according to the present embodiment can also be used to detect the separation position of the airflow. The airflow separation detection system 20 according to the present embodiment also functions as an airflow separation position detection system.

Further, with this configuration, the position where the air current a peels off from the surface of the object 100 can be accurately detected using only the plurality of plasma actuators 1 without using other sensors.

The detection of the peeling position of the air flow a by the air flow peeling position detecting system 20 may be performed by the detecting device 8 (see fig. 8) or may be performed by a device different from the detecting device 8.

The present invention is not limited to the above-described embodiments, and can be modified as appropriate without departing from the spirit of the present invention.