Experimental monitoring device and method for jet vortex shedding and breaking in counter / co-rotating environment

Abstract

The application discloses an experimental monitoring device and method for jet vortex shedding and breaking in counter-rotation environment. The model is divided into a water body configuration part, a jet generation part, a water body environment field part, a flow field structure monitoring part and an accessory support part. The application can realize the conversion of uniform non-rotating jet flow in laminar state / non-uniform rotating jet flow in turbulent state in the centrifugal stability / unstable or non-centrifugal state of the relative environment fluid by opening different components and configurations; the optical matching box eliminates optical distortion, the non-invasive real-time digital particle image velocimetry system and the high-definition camera combination shooting system are selected to measure, and the accuracy of experimental data can be guaranteed to the maximum extent; the development mechanism of spiral vortex winding, shedding and breaking, K-H instability, the relationship between centrifugal stability and instability can be explored, and the flow criticality, stability and intermittence of the jet flow under complex working conditions are clear.

Description

Technical Field

[0001] The present invention relates to the field of physical model experiments in turbulent vortex dynamics, and in particular to an experimental monitoring device and method for jet vortex shedding and breakup in counter-rotating / co-rotating environments. Background Art

[0002] A swirling jet is a complex flow derived from the rotation of a free jet, often in a turbulent state. A swirling jet differs from a conventional jet in the presence of a tangential velocity, which causes the fluid within the nozzle to rotate, resulting in a tangential velocity component in the ejected fluid. In addition to the axial and radial velocity components present in a swirling jet, the swirling velocity (tangential velocity) generates radial and axial pressure gradients, affecting the overall flow field. Swirling jets are ubiquitous in both the natural environment and industrial engineering, with applications in areas such as engine fuel injection systems, boiler fuel injectors, the chemical industry, and oil drilling technology. Specifically, swirling jets can promote localized combustion and mixing between propulsion systems and chemical reactors. Furthermore, aircraft tail vortices and vortices generated by wind shear are major causes of aircraft accidents. Furthermore, tornadoes, hurricanes, and large-scale vortices generated by surface flow disturbances in the atmosphere and ocean can all be generalized as swirling jets. Therefore, understanding the local, global, and linear, and nonlinear flow field structures of swirling jets is crucial for environmental protection and production and life.

[0003] Indoor experiments are an effective means of exploring the macro- and microscopic structures and dynamic characteristics of rotating jets. However, predecessors have focused more on simulating simple working conditions of non-rotating jets, combining particle image velocimetry technology and high-definition camera photography to quantify the structural evolution of jet vortices in non-rotating environments. At present, research on the macro- and microscopic dynamic characteristics of rotating jets is still quite insufficient, and devices that comprehensively consider the influence of anti- and co-rotating environments are even rarer, which further restricts research progress in related fields. Based on this, the present invention proposes an experimental monitoring device for jet vortex shedding and breakup in anti- and co-rotating environments. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the present invention provides an experimental monitoring device and method for jet vortex shedding and breakup in a counter-rotating / co-rotating environment.

[0005] The experimental monitoring device for jet vortex shedding and breakup in counter-rotating / co-rotating environments is divided into a water body configuration part, a jet generation part, a water body environment field part, a flow field structure monitoring part and an accessory support part.

[0006] The water configuration part includes a water reservoir, a water pump and a constant head water tank; the water pump draws water from the water reservoir to the constant head water tank.

[0007] The jet generating part includes a rotary sealing valve, a rotary tube, a honeycomb flow stabilizing tube and a replaceable nozzle;

[0008] The inlet of the rotary sealing valve is connected to the constant head water tank to control the one-way inflow of water; the outlet of the rotary sealing valve is connected to one end of the rotary tube, and the other end of the rotary tube is connected to the honeycomb flow stabilizing tube. The rotary tube rotates while driving the honeycomb flow stabilizing tube to rotate coaxially;

[0009] The honeycomb flow stabilizing tube allows the water flow to enter the replaceable nozzle stably and evenly;

[0010] The replaceable nozzles are divided into a contraction type and a non-contraction type. The contraction nozzle is used to configure a uniform irrotational jet in a laminar state, and the non-contraction nozzle is used to configure a non-uniform rotatory jet in a turbulent state.

[0011] The water environment field part includes an experimental water tank and an optical matching box;

[0012] The optical matching box encloses an experimental water tank, and the replaceable nozzle is located in the experimental water tank; the optical matching box plays a role in eliminating optical distortion.

[0013] The flow field structure monitoring part includes a real-time digital particle image velocimeter system and a high-definition camera combined shooting system.

[0014] The real-time digital particle image velocimetry system monitoring includes a laser source, a rotatable reflector, and a visual image acquisition CCD camera;

[0015] The laser source adopts an argon ion laser to generate a laser beam and irradiate the experimental water tank;

[0016] The rotatable reflector is placed near the optical matching box, and the laser beam is refracted by adjusting its placement angle;

[0017] The visual image acquisition CCD camera faces the experimental water tank and continuously takes pictures to obtain the jet flow field;

[0018] The high-definition camera combination shooting system includes two high-definition digital cameras and a fixed reflector;

[0019] The two high-definition digital cameras are used to obtain the geometric shapes of jets with different configurations. One high-definition digital camera faces the experimental water tank and continuously shoots to obtain the two-dimensional shape of the jet from the side, and the other high-definition digital camera is placed at the bottom of the optical matching box and is combined with the fixed reflector to continuously shoot the two-dimensional shape of the jet from the top.

[0020] The accessory support part includes an environmental water body rotating platform, a rotating platform control system and a supporting platform; the environmental water body rotating platform is connected to the experimental water tank and the optical matching box, and its rotation simultaneously drives the experimental water tank and the optical matching box to rotate;

[0021] The rotating platform control system controls the rotating platform's rotation speed and direction in the surrounding water body;

[0022] The support platform is used to support the water body rotating platform and the rotating platform control system.

[0023] An experimental method for monitoring jet vortex shedding and breakup in counter-rotating / co-rotating environments, using the above-mentioned apparatus, comprises the following steps:

[0024] (a) Before the test begins, the reservoir is filled with clean water and allowed to stand for several days to allow the air to escape.

[0025] If the vortex distribution and flow field structure of the configured jet are to be investigated, a small amount of polymer particles are added to the clean water as a tracer, and a real-time digital particle image velocimeter system is activated. If the geometric shape of the configured jet is to be investigated, no polymer particles are added to the clean water in the reservoir, and a high-definition camera combination shooting system is activated.

[0026] The basis for selecting the nozzle is as follows: the convergent nozzle is used to configure the uniform irrotational jet in the laminar state, and the non-convergent nozzle is used to configure the non-uniform rotatory jet in the turbulent state.

[0027] (b) Start the test. Turn on the pump to pump water from the reservoir into the constant head tank. Use the flow meter to control the flow rate. Select the configuration and start it. For example, consider the case of a non-uniform rotating flow with turbulent initial jet flow and focus on the vortex distribution and flow field structure under centrifugal instability:

[0028] The environmental water rotating stage is rotated by the rotating stage control system, and the environmental water is completely rigidified after working for several hours; the real-time digital particle image velocimeter system is started, the rotatable reflector is adjusted so that the laser slice is located in the study area, and the visual image acquisition CCD camera is turned on; a non-constriction nozzle is selected to configure a turbulent non-uniform rotating jet, the motor is turned on, and the rotating tube drives the honeycomb flow stabilization tube and the nozzle to rotate, and the rotation direction is opposite to the coaxial experimental water tank and optical matching box to shape the initial configuration of centrifugal instability; the flow meter is adjusted, the spinning jet is injected into the counter-rotating environmental fluid, and the visual image acquisition CCD camera is used for continuous shooting. The outflow pipe is connected to the experimental water tank, and the experimental water flow is discharged to the external environment.

[0029] (c) After the test, turn off the power unit and return the water in the constant head water tank to the reservoir for use in the next test.

[0030] (d) Data processing: Post-processing of images from the real-time digital particle image velocimeter system to obtain the vortex distribution and flow field structure of the uniform irrotational jet in the laminar state / the non-uniform irrotational jet in the turbulent state when the jet is centrifugally stable / unstable or non-centrifugally relative to the ambient fluid; post-processing of images from the high-definition camera combination shooting system to obtain the geometric shape of the uniform irrotational jet in the laminar state / the non-uniform irrotational jet in the turbulent state when the jet is centrifugally stable / unstable or non-centrifugally relative to the ambient fluid.

[0031] Beneficial effects of the present invention:

[0032] 1. The device of the present invention has an ingenious structure, good integrity, high efficiency and low device cost.

[0033] 2. The device of the present invention can realize the conversion of uniform irrotational jet in laminar state / non-uniform rotatory jet in turbulent state under multiple working conditions such as centrifugal stability / instability or non-centrifugal relative to the ambient fluid by opening different components and configurations.

[0034] 3. Using an optical matching box to eliminate optical distortion and selecting a non-invasive real-time digital particle image velocimetry (DPIV) system and a high-definition camera combined shooting system can maximize the accuracy of experimental data.

[0035] 4. The present invention can explore the development mechanism of spiral vortex entanglement, shedding, and breakage, the relationship between KH instability and centrifugal stability / instability, and clarify the flow criticality, stability, and intermittency of jets under complex working conditions (co-rotating and counter-rotating).

[0036] 5. The device and consumables of the present invention can be recycled and reused, which meets the requirements of green economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the main view of the device of the present invention.

[0038] Figure: 1. Water reservoir, 2. Water pump, 3. Constant-head water tank, 4. Overflow pipe, 5. Flowmeter, 6. Rotary seal valve, 7. Motor, 8. Rotating tube, 9. Honeycomb flow stabilization tube, 10. Replaceable nozzle, 11. Experimental water tank, 12. Optical matching box, 13. Control valve, 14. Outlet pipe, 15. Laser source, 16. Rotatable reflector, 17. Visual image acquisition CCD camera, 18. Side-view HD camera, 19. Top-view HD camera, 20. Fixed reflector, 21. Rotating stage, 22. Support platform, 23. Rotating stage control system, 24. Flow guide tube. DETAILED DESCRIPTION

[0039] The present invention will be further described below with reference to the accompanying drawings.

[0040] like Figure 1 As shown, the model of the present invention is divided into a water body configuration part, a jet generation part, a water body environment field part, a flow field structure monitoring part and an accessory support part.

[0041] The water body configuration part includes a water reservoir 1, a water pump 2, a constant head water tank 3, an overflow pipe 4, and a flow meter 5; the water reservoir contains clean water (precipitates and rust have been filtered out using a filter), which is left to stand for several days to exhaust air. For some experimental groups, a small amount of polymer particles are added as a tracer to visualize the flow field; the water pump draws water from the water reservoir to the constant head water tank; the overflow pipe is used to discharge excess water from the constant head water tank, providing a constant head to reduce water flow oscillations caused by the work of the water pump; and the flow meter records the flow rate of the water passing through.

[0042] The jet generating part includes a rotary sealing valve 6, a motor 7, a rotating tube 8, a honeycomb flow stabilizing tube 9, and a replaceable nozzle 10; the rotary sealing valve controls the unidirectional inflow of water and prevents the water flow in the rotating tube from leaking out; the motor provides a power source for the rotation of the rotating tube; the rotating tube is directly connected to the motor and the honeycomb flow stabilizing tube, and drives the honeycomb flow stabilizing tube to rotate coaxially while spinning; the honeycomb flow stabilizing tube allows the water flow to enter the replaceable nozzle stably and evenly; the replaceable nozzle is divided into a contraction type and a non-contraction type, the contraction nozzle is used to configure a uniform non-rotational jet in a laminar state, and the non-contraction nozzle is used to configure a non-uniform rotating jet in a turbulent state.

[0043] The water environment field part includes an experimental water tank 11, an optical matching box 12, a control valve 13, and an outlet pipe 14; the optical matching box envelops the experimental water tank; the experimental water tank and the optical matching box are both made of transparent materials; the experimental water tank and the optical matching box are both filled with homogeneous clean water and are coaxial with the nozzle assembly, and the optical matching box plays a role in eliminating optical distortion; the control valve controls the water flow in the experimental water tank; the outlet pipe is connected to the experimental water tank and diverts the experimental water flow to the external environment (the water body is not reused); the outlet pipe is designed with multiple outlets to minimize the impact of outflow disturbance on the development of jet vortex.

[0044] The flow field structure monitoring part includes a real-time digital particle image velocimeter (DPIV) system and a high-definition camera combination shooting system. The real-time digital particle image velocimeter (DPIV) system monitoring includes a laser source 15, a rotatable reflector 16, and a visual image acquisition CCD camera 17; the laser source uses an argon ion laser to generate a laser beam and irradiate the experimental water tank; the rotatable reflector is placed near the optical matching box, and the laser beam is refracted by adjusting its placement angle; the visual image acquisition CCD camera faces the experimental water tank and continuously shoots to obtain the jet flow field; the high-definition camera combination shooting system includes two high-definition digital cameras and a fixed reflector 20; the two high-definition digital cameras are used to obtain the geometric shape of jets with different configurations, and one high-definition digital camera 18 faces the experimental water tank and continuously shoots to obtain the side view of the jet. dimensional morphology, another high-definition digital camera 19 is placed at the bottom of the optical matching box, and combined with the fixed reflector (at an angle of 45 degrees to the horizontal plane), it continuously shoots the two-dimensional morphology of the jet when viewed from above; the real-time digital particle image velocimeter (DPIV) system and the high-definition camera combined shooting system do not have to be used at the same time, and can be selected according to experimental needs, that is, the real-time digital particle image velocimeter (DPIV) system is used to configure the vortex distribution and flow field structure of the jet, and the high-definition camera combined shooting system is used to configure the geometric morphology of the jet; if a small amount of polymer particles are added to the clean water in the reservoir as a tracer, the real-time digital particle image velocimeter (DPIV) system is activated, otherwise, the high-definition camera combined shooting system is activated.

[0045] The accessory support part includes an environmental water body rotating table 21, a rotating table control system 23, a support table 22, and a guide tube 24; the environmental water body rotating table is connected to the experimental water tank and the optical matching box, and its rotation simultaneously drives the experimental water tank and the optical matching box to rotate; the rotating table control system controls the rotation speed and direction of the environmental water body rotating table; the support table is used to support the water body rotating table and the rotating table control system; the guide tube is connected to the above-mentioned water reservoir, constant head water tank and rotating tube.

[0046] The present invention provides an experimental method for monitoring jet vortex shedding and breakup in counter-rotating / co-rotating environments, specifically:

[0047] (a) Before the experiment began, the reservoir was filled with clean water and allowed to stand for several days to allow for degassing. To investigate the vortex distribution and flow field structure of the configured jet, a small amount of polymer particles was added to the clean water as a tracer, and a real-time digital particle image velocimetry (DPIV) system was used. To investigate the geometry of the configured jet, no polymer particles were added to the clean water in the reservoir, and a high-definition camera system was used. Depending on the inlet velocity profile, the initial jet field was set to two types. One type features an inlet profile with axial and azimuthal shear layers. These shear layers overlap closely near or at the edges of the inlet radius. The instability modes are primarily dependent on the local average vortex lines, and the instability mechanism of this type of jet is Kelvin-Helmholtz (KH) type. The other type considers an inlet velocity profile with an azimuthal vorticity peak within the axial shear layer. Due to rotation, the axial flow deviates to some extent from the location of maximum axial vorticity in the azimuthal shear layer. Intermittent co-rotating and co-entwined spiral vortices are the most unstable, and the jet vortex lines are primarily affected by centrifugal instabilities. The nozzle selection is based on the following principles: converging nozzles are used to create laminar, uniform, irrotational jets, while non-converging nozzles are used to create turbulent, non-uniform, swirling jets. This means the swivel motor should be turned off when installing a converging nozzle, and on when installing a non-converging nozzle. The experimental water tank can remain stationary, rotate in the same direction as the jet nozzle (co-rotation), or rotate in the opposite direction (counter-rotation). If the experimental water tank is stationary, the ambient fluid is operating in a non-centrifugal condition. Rotating the experimental water tank and jet nozzle in the same direction (co-rotation) achieves a quasi-centrifugal, stable condition. Rotating the experimental water tank and jet nozzle in the opposite direction (counter-rotation) targets unstable, centrifugal conditions. The configuration selection should be based on the research content, such as the development mechanisms of spiral vortex entanglement, shedding, and fragmentation, KH instability, and the relationship between centrifugal stability and instability.

[0048] (b) Start the test by turning on the pump to pump water from the reservoir into the constant head tank. The constant head tank reduces the water flow oscillation caused by the pump's work and drains excess water back into the reservoir. The flow rate is controlled by a flow meter. Based on the components described above and the corresponding operating conditions, select the configuration and start it. Take the initial jet as a turbulent non-uniform rotating flow, pay attention to the vortex distribution under centrifugal instability and the flow field structure working conditions as an example: rotate the environmental water rotating table through the rotating table control system, and make the environmental water completely rigid after working for several hours; start the real-time digital particle image velocimetry (DPIV) system, adjust the rotatable reflector so that the laser slice is located in the study area, and turn on the visual image acquisition CCD camera; select a non-constriction nozzle to configure the turbulent non-uniform rotating jet, turn on the motor, and the rotating tube drives the honeycomb flow stabilization tube and nozzle to rotate. The rotation direction is opposite to that of the coaxial experimental water tank and optical matching box to shape the initial configuration of centrifugal instability; adjust the flow meter, and the spinning jet is injected into the counter-rotating environmental fluid. The visual image acquisition CCD camera takes continuous pictures. The outflow pipe is connected to the experimental water tank, and the experimental water flow is discharged to the external environment (the water body is not reused).

[0049] (c) After the test, shut down the power unit (motor and turntable control system) and return the water in the constant head water tank to the reservoir for use in the next test.

[0050] (d) Data processing: Post-processing of images from the real-time digital particle image velocimeter (DPIV) system to obtain the vortex distribution and flow field structure of a uniform irrotational jet in a laminar state / a non-uniform irrotational jet in a turbulent state when the jet is centrifugally stable / unstable or non-centrifugally relative to the ambient fluid; post-processing of images from the high-definition camera combination shooting system to obtain the geometric morphology of a uniform irrotational jet in a laminar state / a non-uniform irrotational jet in a turbulent state when the jet is centrifugally stable / unstable or non-centrifugally relative to the ambient fluid.

[0051] In the description of the present invention, it should be understood that the terms "top", "vertical", "bottom", "inside", "side", "vertical", "up", "down", "upper end", "lower", "rear", "height", "front", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0052] In the present invention, unless otherwise specified or limited, terms such as "disposed" and "connected" should be interpreted broadly. For example, they may refer to fixed or detachable connections, or integration; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in the present invention based on specific circumstances.

[0053] The above description of the present invention is only a preferred embodiment of the invention, and does not limit the patent scope of the present invention. Any equivalent structural transformation made by using the contents of the present invention specification, or directly or indirectly applied to the technical field of other related products, is included in the patent protection scope of the present invention.

Claims

1. Experimental monitoring device for jet vortex shedding and breakup in counter-rotating / co-rotating environments, characterized by: It is divided into water body configuration part, jet generation part, water body environment field part, flow field structure monitoring part and accessory support part; The water configuration part includes a water reservoir, a water pump and a constant head water tank; the water pump draws water from the water reservoir to the constant head water tank; The jet generating part includes a rotary sealing valve, a rotary tube, a honeycomb flow stabilizing tube and a replaceable nozzle; The inlet of the rotary sealing valve is connected to the constant head water tank to control the one-way inflow of water; the outlet of the rotary sealing valve is connected to one end of the rotary tube, and the other end of the rotary tube is connected to the honeycomb flow stabilizing tube. The rotary tube rotates while driving the honeycomb flow stabilizing tube to rotate coaxially; The honeycomb flow stabilizing tube allows the water flow to enter the replaceable nozzle stably and evenly; The replaceable nozzles are divided into contraction type and non-contraction type. The contraction nozzle is used to configure a uniform irrotational jet in a laminar state, and the non-contraction nozzle is used to configure a non-uniform rotatory jet in a turbulent state. The water environment field part includes an experimental water tank and an optical matching box; The optical matching box encloses an experimental water tank, and the replaceable nozzle is located in the experimental water tank; the optical matching box plays a role in eliminating optical distortion; The flow field structure monitoring part includes a real-time digital particle image velocimeter system and a high-definition camera combined shooting system; The real-time digital particle image velocimetry system monitoring includes a laser source, a rotatable reflector, and a visual image acquisition CCD camera; The laser source adopts an argon ion laser to generate a laser beam and irradiate the experimental water tank; The rotatable reflector is placed near the optical matching box and reflects the laser beam by adjusting its placement angle; The visual image acquisition CCD camera faces the experimental water tank and continuously takes pictures to obtain the jet flow field; The high-definition camera combination shooting system includes two high-definition digital cameras and a fixed reflector; The two high-definition digital cameras are used to obtain the geometric shapes of jets with different configurations. One high-definition digital camera faces the experimental water tank and continuously captures the side-view two-dimensional shape of the jet. The other high-definition digital camera is placed at the bottom of the optical matching box and is combined with the fixed reflector to continuously capture the upward-view two-dimensional shape of the jet. The accessory support part includes an environmental water body rotating platform, a rotating platform control system and a supporting platform; the environmental water body rotating platform is connected to the experimental water tank and the optical matching box, and its rotation simultaneously drives the experimental water tank and the optical matching box to rotate; The rotating platform control system controls the rotating platform's rotation speed and direction in the surrounding water body; The support platform is used to support the water body rotating platform and the rotating platform control system.

2. The experimental monitoring device according to claim 1, characterized in that: It also includes an overflow pipe, which is used to discharge excess water from the constant head water tank and provide a constant water head to reduce water flow oscillation caused by the work of the water pump.

3. The experimental monitoring device according to claim 1, characterized in that: It also includes an outflow pipe, which is connected to the experimental water tank and guides the experimental water flow to the external environment. A control valve is installed on the outflow pipe.

4. The experimental monitoring device according to claim 1, characterized in that: The real-time digital particle image velocimeter system and the high-definition camera combination shooting system are not used at the same time. The real-time digital particle image velocimeter system is used to configure the vortex distribution and flow field structure of the jet, and the high-definition camera combination shooting system is used to configure the geometric shape of the jet. If a small amount of polymer particles are added to the clean water in the reservoir as a tracer, the real-time digital particle image velocimeter system is activated; otherwise, the high-definition camera combination shooting system is activated.

5. An experimental method for monitoring jet vortex shedding and breakup in counter-rotating / co-rotating environments, using the apparatus according to any one of claims 1 to 4, characterized in that The method comprises the following steps: (a) Before the test begins, the reservoir is filled with clean water; To investigate the vortex distribution and flow field structure of the configured jet, a small amount of polymer particles is added to the clean water as a tracer, and a real-time digital particle image velocimetry system is used. If the geometric shape of the jet configuration is explored, the clean water in the reservoir is not added with polymer particles, and a high-definition camera combination shooting system is enabled; The selection of nozzles is based on the following principles: the convergent nozzle is used to configure a uniform irrotational jet in a laminar state, and the non-convergent nozzle is used to configure a non-uniform swirl jet in a turbulent state; (b) Start the experiment by turning on the water pump to pump the water in the reservoir into the constant head water tank and control the flow rate with a flow meter. Select the configuration and start it. If the initial jet is configured as a turbulent non-uniform rotating flow, pay attention to the vortex distribution and flow field structure conditions under centrifugal instability: rotate the environmental water rotating table through the rotating table control system, and make the environmental water completely rigid after working for several hours. Start the real-time digital particle image velocimeter system, adjust the rotatable mirror so that the laser slice is located in the study area, and turn on the visual image acquisition CCD camera. Select a non-converging nozzle to configure a turbulent non-uniform rotating jet, turn on the motor, and the rotating tube drives the honeycomb flow stabilization tube and nozzle to rotate in the opposite direction of the coaxial experimental water tank and optical matching box to shape the initial configuration of centrifugal instability. Adjust the flow meter so that the spinning jet is injected into the counter-rotating environmental fluid. The visual image acquisition CCD camera takes continuous pictures. The outflow pipe is connected to the experimental water tank and the experimental water flow is discharged to the external environment. (c) After the test, shut down the power unit and return the water in the constant head water tank to the reservoir for use in the next test; (d) Data processing: Post-processing of images from the real-time digital particle image velocimeter system to obtain the vortex distribution and flow field structure of the uniform irrotational jet in the laminar state / the non-uniform irrotational jet in the turbulent state when the jet is centrifugally stable / unstable or non-centrifugally relative to the ambient fluid; post-processing of images from the high-definition camera combination shooting system to obtain the geometric shape of the uniform irrotational jet in the laminar state / the non-uniform irrotational jet in the turbulent state when the jet is centrifugally stable / unstable or non-centrifugally relative to the ambient fluid.

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