Fluid analysis device, fluid analysis system, and fluid analysis method

Abstract

To provide a fluid analysis device capable of visualizing airflow over the entire observation area by obtaining the current vector distribution over the entire observation area when visualizing airflow using intermittent smoke, a fluid analysis system, and a fluid analysis method.SOLUTION: Within the unit observation time ΔT, during which at least one intermittent smoke SM passes through an observation area E, the flow velocity vector V is calculated continuously based on the density of smoke in multiple small calculation areas EE that form the observation area E. Defining the maximum flow velocity vector of each micro-calculation area EE within the unit observation time ΔT as the determined flow velocity vector D1 of each micro-calculation area EE, the air flow throughout the observation area E is visualized by using the determined flow velocity vector D1.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a fluid analysis apparatus, a fluid analysis system, and a fluid analysis method capable of obtaining a flow velocity vector distribution over the entire observation region and visualizing the airflow over the entire observation region when visualizing the airflow using intermittent smoke.

Background Art

[0002] Conventionally, a wind tunnel test system for observing the airflow around an object such as a vehicle is known. For example, when measuring the influence of wind during the running of a vehicle, the vehicle is installed in a wind tunnel test system, smoke is ejected from a smoke outflow nozzle toward the vehicle, and an image around the vehicle is captured by a camera. Then, by performing PIV (Particle Image Velocimetry) analysis on the image captured by the camera, the airflow around the vehicle is observed.

[0003] For this reason, Patent Document 1 discloses a wind tunnel test apparatus for visualizing the streamline of smoke around a measurement object ejected toward the measurement object. By using such Patent Document 1, the path of the airflow around the measurement object can be measured as a line.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, in the case of the above Patent Document 1, since smoke is continuously injected from the smoke outflow nozzle to the vehicle, the smoke may be uniformly mixed. As a result, the density and shape of the smoke required for PIV analysis may not occur, and there may be a problem that the airflow cannot be analyzed. In particular, the visualization of the airflow at a relatively high wind speed (30 to 60 km / h) assuming the vehicle running speed is difficult because the fine particles are uniformly distributed.

[0006] Therefore, the present inventors have found that by flowing intermittent smoke in which smoke is intermittently flowed to the object to be measured, it is possible to give density to the airflow, and the flow velocity vector of any part of the observation region can be obtained from the density of this smoke and the airflow can be visualized.

[0007] However, since the airflow that can be visualized is only the part through which the intermittent smoke has passed, it is partial and instantaneous, and it has been difficult to obtain the distribution of the flow velocity vectors over the entire observation region and visualize the airflow over the entire observation region.

[0008] The present invention has been made in view of the above, and an object thereof is to provide a fluid analysis device, a fluid analysis system, and a fluid analysis method capable of obtaining a distribution of flow velocity vectors over the entire observation region and visualizing the airflow over the entire observation region when visualizing the airflow using intermittent smoke.

Means for Solving the Problems

[0009] In order to solve the above-described problems and achieve the object, a fluid analysis apparatus according to the present invention flows intermittent smoke, in which smoke is intermittently flowed against a steady flow of air, to an object to be measured, and analyzes the air flow in the observation region around the object to be measured based on an image obtained by imaging the flow of the intermittent smoke in the observation region. The fluid analysis apparatus is characterized in that, within a unit observation time during which at least one intermittent smoke passes through the observation region, a flow velocity vector is continuously calculated based on the density of the smoke in a plurality of minute calculation regions forming the observation region, and the maximum flow velocity vector of each minute calculation region within the unit observation time is used as the determined flow velocity vector of each minute calculation region to visualize the air flow in the entire observation region.

[0010] Further, the fluid analysis apparatus according to the present invention is characterized in that, in the above invention, the average value of a plurality of determined flow velocity vectors obtained in consecutive unit observation times is used as the determined flow velocity vector of each minute calculation region to visualize the air flow in the entire observation region.

[0011] Further, a fluid analysis system according to the present invention includes an intermittent smoke generator that flows intermittent smoke, in which smoke is intermittently flowed against a steady flow of air, to an object to be measured, an imaging device that images the flow of the intermittent smoke in the observation region around the object to be measured, and a fluid analysis apparatus that analyzes the air flow in the observation region based on the image captured by the imaging device. The fluid analysis apparatus is characterized in that, within a unit observation time during which at least one intermittent smoke passes through the observation region, a flow velocity vector is continuously calculated based on the density of the smoke in a plurality of minute calculation regions forming the observation region, and the maximum flow velocity vector of each minute calculation region within the unit observation time is used as the determined flow velocity vector of each minute calculation region to visualize the air flow in the entire observation region.

[0012] Further, the fluid analysis system according to the present invention is characterized in that, in the above invention, the average value of a plurality of determined flow velocity vectors obtained in consecutive unit observation times is used as the determined flow velocity vector of each minute calculation region to visualize the air flow in the entire observation region.

[0013] Also, the fluid analysis method according to the present invention flows intermittent smoke, in which smoke is intermittently flowed through a steady flow of air, over a measurement object, and analyzes the air flow in an observation region around the measurement object based on an image obtained by imaging the flow of the intermittent smoke in the observation region. The fluid analysis method is characterized in that, within a unit observation time during which at least one or more intermittent smokes pass through the observation region, a flow velocity vector is continuously calculated based on the density of the smoke in a plurality of minute calculation regions forming the observation region, and the maximum flow velocity vector of each minute calculation region within the unit observation time is used as the determined flow velocity vector of each minute calculation region to visualize the air flow over the entire observation region.

[0014] Also, the fluid analysis method according to the present invention is characterized in that, in the above invention, the average value of a plurality of determined flow velocity vectors obtained in consecutive unit observation times is used as the determined flow velocity vector of each minute calculation region to visualize the air flow over the entire observation region.

Advantages of the Invention

[0015] According to the present invention, when visualizing an air current using intermittent smoke, it is possible to obtain a flow velocity vector distribution over the entire observation region and visualize the air current over the entire observation region.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

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Figure 8

Mode for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0018] <Concept of Fluid Analysis> FIG. 1 is an explanatory diagram for explaining the concept of fluid analysis processing by the fluid analysis apparatus according to the present embodiment. This fluid analysis processing is a process of flowing intermittent smoke SM, in which smoke is intermittently flowed with respect to a steady flow of air, over a measurement object, and analyzing the air flow in the entire observation region E around the measurement object based on an image obtained by imaging the flow of the intermittent smoke SM in the observation region E.

[0019] As shown in FIG. 1, the intermittent smoke SM passes through the observation region E between time point t1 and time point t5. The time from time point t1 to time point t5 when this intermittent smoke SM passes through the observation region E is defined as the unit observation time ΔT. Time point t1 is the time when the front end of the intermittent smoke SM enters the observation region E, and time point t5 is the time when the rear end of the intermittent smoke SM exits the observation region E. Also, time point t2 is the time when 2 / 3 of the intermittent smoke SM enters the observation region E. Further, time point t3 is the time when the center of the intermittent smoke SM is located at the center of the observation region E. Furthermore, time point t4 is the time when 1 / 3 of the intermittent smoke SM exits the observation region E. Note that time points t1 to t5 are representative time points, and the intermittent smoke SM moves moment by moment from time point t1 to time point t5.

[0020] Here, the observation region E is continuously imaged over time by an imaging unit such as a high-speed camera. In the fluid analysis process, the observation region E is divided into minute calculation regions EE arranged in a grid pattern, for example. The flow velocity vector V in each minute calculation region EE is sequentially obtained during the unit observation time ΔT based on the change in the density of the smoke due to the intermittent smoke SM. The shape of the minute calculation region EE is a rectangular shape such as a square or a rectangle, for example. Also, the size of the minute calculation region EE can be arbitrarily set.

[0021] The flow velocity vector V is obtained by identifying a portion with a relatively high phase difference between the luminance distribution of the minute calculation region EE in the image at the first time of two temporally continuous images and the luminance distribution of a search region wider than the minute calculation region EE in the image at the second time. The flow velocity vector V indicates the direction and velocity of the air flow. If there is a change in the density of the smoke in the minute calculation region EE, the flow velocity vector V can be obtained. However, for example, before the intermittent smoke SM passes or after the intermittent smoke SM passes, if there is no change in the density of the smoke in the minute calculation region EE, the flow velocity vector V cannot be obtained.

[0022] In the fluid analysis process according to the present embodiment, during the unit observation time ΔT, an operation for continuously obtaining the flow velocity vector V in each minute calculation region EE is performed, and the maximum flow velocity vector of each minute calculation region EE within the unit observation time ΔT is determined as the determined flow velocity vector D1 of each minute calculation region EE. As shown in FIG. 1(f), the determined flow velocity vector D1 for the entire observation region E, that is, for all the minute calculation regions EE, is obtained. Since the intermittent smoke SM passes through all the minute calculation regions EE during the unit observation time ΔT, the density of the smoke changes, and the determined flow velocity vector D1 for all the minute calculation regions EE can be obtained. Thereby, the air flow over the entire observation region E can be visualized.

[0023] <Fluid analysis device> FIG. 2 is a block diagram showing the configuration of the fluid analysis device 1. As shown in FIG. 2, the fluid analysis device 1 includes an input unit 2, a display unit 3, a storage unit 4, and a control unit 5. The input unit 2 is an input interface such as a mouse or a keyboard for performing various operation inputs. The display unit 3 is an output interface such as a liquid crystal device for performing display outputs of various contents. The storage unit 4 is a storage device composed of a hard disk device, a non-volatile memory, etc., and stores continuous captured images D0 of the observation region E, a determined flow velocity vector D1, a flow velocity vector diagram D2, a unit observation time ΔT, etc.

[0024] The control unit 5 is a control unit that controls the entire fluid analysis device 1, and includes a flow velocity vector calculation unit 6 and a maximum flow velocity vector determination unit 7. The control unit 5 stores programs corresponding to these flow velocity vector calculation unit 6 and maximum flow velocity vector determination unit 7 in a storage device such as a non-volatile memory or a magnetic disk device, loads these programs into the memory, and executes them with the CPU to execute the corresponding processes.

[0025] The flow velocity vector calculation unit 6 performs a calculation to continuously obtain a flow velocity vector V in each minute calculation region EE during the unit observation time ΔT. The maximum flow velocity vector determination unit 7 determines the maximum flow velocity vector of each minute calculation region EE within the unit observation time ΔT as the determined flow velocity vector D1 of each minute calculation region EE.

[0026] <Fluid analysis process> FIG. 3 is a flowchart showing the fluid analysis processing procedure by the control unit 5 of the fluid analysis apparatus 1. As shown in FIG. 3, first, the control unit 5 acquires continuous captured images D0 of the observation region E for a unit observation time ΔT (step S101). Then, the flow velocity vector calculation unit 6 performs a calculation to continuously obtain the flow velocity vector V in each minute calculation region EE during the unit observation time ΔT (step S102). Then, the maximum flow velocity vector determination unit 7 determines the maximum flow velocity vector of each minute calculation region EE within the unit observation time ΔT as the determined flow velocity vector D1 of each minute calculation region EE (step S103). Then, the control unit 5 displays a flow velocity vector diagram over the entire observation region E on the display unit 3 based on the determined flow velocity vector D1, visually displays the air flow (step S104), and ends this processing.

[0027] <Fluid analysis system> FIG. 4 is a schematic diagram showing the configuration of the fluid analysis system 10 according to the present embodiment. This fluid analysis system 10 is, for example, a wind tunnel test system. The fluid analysis system 10 shown in FIG. 4 generates wind at a constant speed (for example, 30 km / h) from the blower unit 30 in the wind tunnel 20, and sends the intermittently generated smoke from the smoke generator 60 to the object to be measured 100. Then, the movement of the smoke around the object to be measured 100 is imaged by the imaging unit 40, and the air flow of the object to be measured 100 is analyzed by analyzing the captured continuous images with the fluid analysis apparatus 1.

[0028] As shown in FIG. 4, the fluid analysis system 10 includes a wind tunnel 20, a wind tunnel window 21, a blower unit 30, an imaging unit 40, a fluid analysis apparatus 1, and a smoke generator 60. Further, the object to be measured 100 is suspended from the ceiling of the wind tunnel 20 by a wire 101. The wind tunnel 20 has a rectangular prism shape surrounded by walls on all four sides, and the blower unit 30 is disposed at one end of the open end. In addition, in order to image the inside of the wind tunnel 20, a wind tunnel window 21 made of transparent acrylic or the like is disposed on a part of the four walls. The region imaged through this wind tunnel window 21 is the observation region E.

[0029] The air supply unit 30 is a device that supplies air at a predetermined wind speed to the wind tunnel 20. The imaging unit 40 images the flow of smoke around the object 100 to be measured and transmits the captured continuous images to the fluid analysis device 1. The fluid analysis device 1 performs the processing as described above. The smoke generator 60 is installed outside the wind tunnel 20 and is a device that intermittently generates smoke into the wind tunnel 20 by means of a cylindrical part.

[0030] <Smoke generator> FIG. 5 is a perspective view showing the configuration of the smoke generator 60 shown in FIG. 4. As shown in FIG. 5, the smoke generator 60 includes a smoke generation part 61, a cylindrical part 62, another cylindrical part 63, a disk sandwiching part 64, a disk part 65, a drive part 66, and a drive control part 67. Further, the disk part 65 has a plurality of holes 68 penetrating the disk part 65.

[0031] The smoke generation part 61 is a part that continuously generates smoke. The generation of smoke is, for example, by heating and vaporizing a liquid mainly composed of glycogen and then adiabatically expanding to generate smoke. The cylindrical part 62 is a pipe that guides the smoke generated by the smoke generation part 61 to the disk part 65. The cylindrical part 63 is a pipe that guides the smoke that has passed through the cylindrical part 62 and the holes 68 provided in the disk part 65 to the object 100 to be measured.

[0032] The disk sandwiching part 64 is a jig with the cylindrical part 62 connected to one end and the cylindrical part 63 connected to the other end, and sandwiches the disk part 65 between the connection part of the cylindrical part 62 and the connection part of the cylindrical part 63.

[0033] The disk part 65 has a circular plate-like structure, and holes 68 are provided at predetermined intervals on the outer peripheral part. The drive part 66 rotates the disk part 65 at a predetermined rotational speed. The drive part 66 is connected to the disk part 65. The drive control part 67 is a control part that controls the drive part 66 so that the disk part 65 reaches a predetermined rotational speed.

[0034] The smoke generation unit 61 has one end of the cylindrical part 62 connected to the smoke output part, and the smoke generated from the smoke generation unit 61 is guided to the cylindrical part 62. The other end of the cylindrical part 62 is connected to the disk clamping part 64. One end of the cylindrical part 63 is connected to the disk clamping part 64, and the smoke guided to the cylindrical part 62 passes through the hole 68 provided in the disk part 65 and is injected from the cylindrical part 63 to the object to be measured 100.

[0035] The disk part 65 is clamped between the cylindrical part 62 and the cylindrical part 63 of the disk clamping part 64. The driving part 66 is fixed to the disk clamping part 64 by a jig, and the driving part 66 and the disk part 65 are connected by a driving shaft. The central axis of the circle of the disk part 65 is aligned with the rotation axis of the driving part 66 and they are connected using the driving shaft. With this structure, the disk part 65 rotates in a predetermined direction at a predetermined rotational speed by the driving part 66.

[0036] The disk part 65 of the smoke generating device 60 is inserted above the disk clamping part 64 and installed between the cylindrical part 62 and the cylindrical part 63. And the disk part 65 serves as a shutter that opens and closes the opening of the smoke passage formed by the cylindrical part 62, the cylindrical part 63, and the disk part 65. Specifically, when the cylindrical part 62, the hole 68 of the disk part 65, and the opening of the cylindrical part 63 overlap, the smoke generated by the smoke generation unit 61 passes through the cylindrical part 62 and the hole 68 of the disk part 65 and is injected from the cylindrical part 63 to the object to be measured 100. Also, when the hole 68 of the disk part 65 does not overlap with the openings of the cylindrical part 62 and the cylindrical part 63, the smoke generated by the smoke generation unit 61 cannot pass through the disk part 65 and is not injected from the cylindrical part 63. Therefore, by rotating the disk part 65 in a predetermined direction, smoke can be intermittently injected.

[0037] The disk part 65 has a hole 68 at a location close to the outer periphery of the disk part 65. The holes 68 are provided at equal intervals on the circumference inside the outer circumference of the disk of the disk part 65. For example, when four holes 68 are provided in the disk part 65, they will be provided at 90° intervals.

[0038] Since the disk part 65 rotates while being sandwiched by the disk sandwiching part 64, as the material of the disk part 65, a material having low friction, high heat resistance, and chemical resistance is preferable. For example, polytetrafluoroethylene (PTFE) or the like is preferable.

[0039] FIG. 6 is a diagram showing an example of the generation state of the intermittent smoke SM in the fluid analysis system 10. As shown in FIG. 6, in the wind tunnel 20, since the intermittent smoke SM is injected by the smoke generator 60, a space where the intermittent smoke SM exists and a space where the intermittent smoke SM does not exist can be generated.

[0040] By intermittently injecting the intermittent smoke SM into the wind tunnel 20, the density of the smoke can be generated in the wind tunnel 20, and the flow velocity vector V of the airflow around the object to be measured 100 is obtained and visualized by the intermittent smoke SM.

[0041] <An example of the flow velocity vector diagram> FIG. 7 is a diagram showing an example of the flow velocity vector diagram D2. The flow velocity vector diagram D2 is a diagram showing the determined flow velocity vector D1 in the minute calculation region EE, and the direction of the determined flow velocity vector D1 is indicated by an arrow, and the magnitude of the flow velocity is indicated by a change in color.

[0042] As shown in FIG. 7(a), in the flow velocity vector diagram D2 of the present embodiment, the determined flow velocity vector D1 is displayed over the entire observation region E. In this flow velocity vector diagram D2, it is shown that a swirling flow is formed inside the object to be measured 100 in the region C, and the state where the airflow stays in the region C can be measured. Also, in the region D, the airflow directed downward of the object to be measured 100 can be measured.

[0043] On the other hand, in the conventional flow velocity vector diagram shown in FIG. 7(b), the flow velocity vector VD at a certain moment in the observation region E is displayed, and the flow velocity vector VD only in the region where the intermittent smoke SM exists is displayed. As a result, the flow velocity becomes 0 in the regions F and G where the intermittent smoke SM does not exist, the flow velocity vector VD is not displayed, and the information of the regions F and G cannot be obtained. That is, the information of the flow velocity vector over the entire observation region E cannot be obtained.

[0044] <Modification Example 1> FIG. 8 is a flowchart showing the fluid analysis processing procedure according to Modification Example 1. The fluid analysis processing according to this Modification Example 1 is a process of visualizing the air flow over the entire observation region E by using the average value of a plurality of determined flow velocity vectors D1 obtained within a continuous unit observation time ΔT as the determined flow velocity vector D1 of each minute calculation region EE.

[0045] As shown in FIG. 8, first, the control unit 5 acquires a continuous captured image D0 of the unit observation time ΔT of the observation region E (step S201). Then, the flow velocity vector calculation unit 6 performs a calculation to continuously obtain the flow velocity vector V in each minute calculation region EE during the unit observation time ΔT (step S202). Then, the maximum flow velocity vector determination unit 7 determines the maximum flow velocity vector of each minute calculation region EE within the unit observation time ΔT as the provisional determined flow velocity vector of each minute calculation region EE (step S203).

[0046] Thereafter, it is determined whether or not the unit observation time ΔT has been continuously measured a predetermined number of times (step S204). If the unit observation time ΔT has not been continuously measured a predetermined number of times (step S204: No), a continuous captured image D0 of the next unit observation time ΔT is acquired (step S205), and the process proceeds to step S202 to repeat the process of obtaining the provisional determined flow velocity vector within this next unit observation time ΔT.

[0047] On the other hand, when the unit observation time ΔT is continuously measured a predetermined number of times (step S204: Yes), for each micro calculation area EE, the average value of the predetermined number of temporarily determined flow velocity vectors is determined as the determined flow velocity vector D1 (step S206). Then, based on the determined flow velocity vector D1, the control unit 5 displays a flow velocity vector diagram over the entire observation area E on the display unit 3, visually displays the air flow (step S207), and ends this process. As a result, the determined flow velocity vector D1 of each micro calculation area EE can be stably obtained.

[0048] In addition, in the above-described embodiments and modification examples, when the period of the intermittent smoke SM is short, there may be a plurality of intermittent smokes SM within the unit observation time ΔT. However, even if there are a plurality of intermittent smokes SM, there is no change in obtaining the maximum flow velocity vector of each micro calculation area EE.

[0049] Also, in the present embodiment and modification examples, a steady airflow at a high wind speed (30 to 60 km / h) is assumed. For example, when the wind speed is 30 km / h, if the period of the intermittent smoke SM in the observation area E is set to 5 to 6 times / s, a good flow velocity vector diagram over the entire observation area E can be obtained. Such a relationship between the wind speed and the intermittent smoke SM is preferably obtained as a set value through various experiments in advance.

[0050] Furthermore, in the present embodiment and modification examples, for example, since white smoke is used as the intermittent smoke SM, the background of the observation area E is preferably black, which has a large luminance difference from white.

[0051] Note that each configuration illustrated in the above-described embodiments and each modification example is functionally schematic, and it is not necessarily physically configured as illustrated. That is, the form of dispersion and integration of each device is not limited to that illustrated, and all or part of it can be functionally or physically dispersed and integrated in arbitrary units according to various loads, usage situations, etc.

Industrial Applicability

[0052] The fluid analysis device, fluid analysis system, and fluid analysis method according to the present invention are useful when it is desired to obtain a flow velocity vector distribution over the entire observation region and visualize the airflow over the entire observation region when visualizing the airflow using intermittent smoke.

Explanation of Signs

[0053] 1 Fluid analysis device 2 Input unit 3 Display unit 4 Storage unit 5 Control unit 6 Flow velocity vector calculation unit 7 Maximum flow velocity vector determination unit 10 Fluid analysis system 20 Wind tunnel 21 Wind tunnel window 30 Air blowing unit 40 Imaging unit 60 Smoke generation device 61 Smoke generation part 62, 63 Cylindrical part 64 Disk sandwiching part 65 Disk part 66 Driving part 67 Drive control unit 68 Hole 100 Object to be measured 101 Wire C, D, F, G regions D0 Captured image D1 Determined flow velocity vector D2 Flow velocity vector diagram E Observation region EE Micro calculation region SM Intermittent smoke t1 to t5 Time points V, VD Flow velocity vector ΔT Unit observation time

Claims

1. A fluid analysis device that intermittently flows intermittent smoke, in which smoke is intermittently flowed against a steady flow of air, against an object to be measured, and analyzes the air flow in the observation region based on an image obtained by imaging the flow of the intermittent smoke in the observation region around the object to be measured, wherein within a unit observation time during which at least one intermittent smoke passes through the observation region, a flow velocity vector is continuously calculated based on the density of the smoke in a plurality of minute calculation regions forming the observation region, and the maximum flow velocity vector of each minute calculation region within the unit observation time is used as the determined flow velocity vector of each minute calculation region to visualize the air flow in the entire observation region. A fluid analysis device characterized by this.

2. The fluid analysis device according to claim 1, characterized in that the average value of a plurality of determined flow velocity vectors obtained for consecutive unit observation times is used as the determined flow velocity vector of each minute calculation region to visualize the air flow in the entire observation region.

3. An intermittent smoke generator that intermittently flows intermittent smoke, in which smoke is intermittently flowed against a steady flow of air, against an object to be measured, an imaging device that images the flow of the intermittent smoke in the observation region around the object to be measured, and a fluid analysis device that analyzes the air flow in the observation region based on an image obtained by the imaging device A fluid analysis system comprising: The fluid analysis device continuously calculates a flow velocity vector based on the density of the smoke in a plurality of minute calculation regions forming the observation region within a unit observation time during which at least one intermittent smoke passes through the observation region, and uses the maximum flow velocity vector of each minute calculation region within the unit observation time as the determined flow velocity vector of each minute calculation region to visualize the air flow in the entire observation region. A fluid analysis system characterized by this.

4. The fluid analysis system according to claim 3, characterized in that the average value of a plurality of determined flow velocity vectors obtained for consecutive unit observation times is used as the determined flow velocity vector of each minute calculation region to visualize the air flow in the entire observation region.

5. A fluid analysis method that intermittently flows intermittent smoke, in which smoke is intermittently flowed against a steady flow of air, against an object to be measured, and analyzes the air flow in the observation region based on an image obtained by imaging the flow of the intermittent smoke in the observation region around the object to be measured, wherein Within a unit observation time during which at least one intermittent smoke passes through the observation region, a flow velocity vector is continuously calculated based on the density of smoke in a plurality of micro-calculation regions forming the observation region, and the maximum flow velocity vector of each micro-calculation region within the unit observation time is used as the determined flow velocity vector of each micro-calculation region to visualize the air flow over the entire observation region. A fluid analysis method characterized by this.

6. The fluid analysis method according to claim 5, characterized in that the average value of a plurality of determined flow velocity vectors obtained for consecutive unit observation times is used as the determined flow velocity vector of each micro-calculation region to visualize the air flow over the entire observation region.

Images