Low-interference tail support system for water tunnel test model

Abstract

The invention discloses a low-interference tail support system for a water tunnel test model, which comprises a connecting rod, a flow guide wing plate, a support rod, an adjustable attack angle clamping mechanism and a water tunnel cover plate which are connected in sequence, wherein the connecting rod is used for fixedly connecting the test model to be tested, and one end of the connecting rod is fixedly connected with the tail part of the test model; the connecting rod is inserted into a hole in the front edge of the flow guide wing plate and fixedly connected with a main body of the flow guide wing plate, and the supporting rod is welded to the upper side face of the flow guide wing plate, so that internal channels of the connecting rod, the supporting rod and the flow guide wing plate are communicated to form a hollow channel; the supporting rod is connected to the water tunnel cover plate through the adjustable attack angle clamping mechanism, and the adjustable attack angle clamping mechanism is provided with a worm and gear rotation angle mechanism which enables the supporting rod, the flow guide wing plate and the connecting rod to rotate together with the test model to adjust the angle. Two rows of vortex generators which are distributed in a staggered manner and are of semispherical bulge structures are arranged at the front edge of the flow guide wing plate. The device has the advantages of being high in deformation resistance, extremely small in flow field interference, high in experiment efficiency, excellent in durability and the like.

Description

Technical Field

[0001] This invention belongs to the technical field of hydrodynamic experimental equipment, and specifically relates to a low-interference tail support system for a water tunnel test model. Background Technology

[0002] Water tunnel experiments are an important method for studying the fluid dynamics characteristics of underwater equipment, such as pulsating pressure, flow-induced vibration, hydrodynamic noise, and flow field properties. The support structure must balance the stability of the model with minimal disturbance to the water flow. Traditional support structures have the following drawbacks: Insufficient stiffness: Ordinary metal support rods are prone to deformation or vibration under high-speed water flow, resulting in model displacement or data distortion; Severe wake interference: An unreasonable design of the support rod cross section (such as a cylindrical shape) can easily cause vortex shedding, interfering with the measurement of the wake field of the model; Model pose adjustment is limited: the existing cornering mechanism has low precision, making it difficult to accurately control the angle of attack, which affects the efficiency of multi-condition experiments; The installation location still needs improvement: the distance between the model and the water tunnel inlet and outlet is not set properly, resulting in uneven inflow or interference from reflected waves at the outlet; Insufficient sealing: Water can easily seep through cable perforations and connections, causing short circuits or corrosion of the sensor; in addition, the pressure near the pulsating pressure sensor will be affected during water seepage, interfering with the test.

[0003] Existing improvement solutions, such as using high-strength alloys or hydraulic adjustment mechanisms, while partially improving rigidity, suffer from high costs and complex structures. While the flow guide design can reduce flow resistance, it increases the device's size and restricts adjustment freedom. Therefore, there is an urgent need for a support device that combines high rigidity, low interference, and easy adjustment to meet the requirements of high-precision water tunnel experiments. Summary of the Invention

[0004] This application aims to solve the problems of insufficient stiffness, large flow field disturbance, and limited model attitude adjustment in traditional support structures, thereby providing a low flow field disturbance adjustable angle of attack tail support system for water tunnel test models, suitable for hydrodynamic characteristic testing of rotating body models such as underwater vehicles.

[0005] To achieve the above objectives, the technical solution of this application provides a low-interference tail support system for a water tunnel test model, characterized in that it includes: a connecting rod (2), a guide vane (3), a support rod (4), an adjustable angle of attack clamping mechanism (5), and a water tunnel cover plate (6) that are fixedly connected in sequence, wherein: the connecting rod (2) is used to fix the test model (1) to be tested, and one end of the connecting rod (2) is fixedly connected to the tail of the test model (1); The connecting rod (2) is inserted into the hole at the front edge of the guide vane (3) and fixedly connected to the main body of the guide vane (3). The support rod (4) is welded to the upper side of the guide vane (3). The internal channels of the connecting rod (2), the support rod (4) and the guide vane (3) are connected to form a hollow channel (2-1). The support rod (4) is connected to the water tunnel cover plate (6) through the adjustable angle of attack clamping mechanism (5), and the adjustable angle of attack clamping mechanism (5) has a worm gear rotation mechanism (5-3) so that the support rod (4), the guide vane (3) and the connecting rod (2) together with the test model (1) can rotate and adjust the angle.

[0006] In one possible design, the inner wall of the hollow channel (2-1) is provided with an insulating bushing (2-2).

[0007] As one possible design, the connecting rod (2) has a sealing ring (2-4) at one end for fixing the test model (1) to be tested to provide a waterproof seal.

[0008] In one possible design, the clamping mechanism (5) has a structural base (5-4) fixedly connected to the cover plate (6); the support rod (4) has a thread (4-1) that is inserted into the guide groove reserved in the water tunnel cover plate (6) and the matching groove at the bottom of the structural base (5-4) of the clamping mechanism (5) to achieve circumferential positioning; the inner ring of the locking cover plate (5-1) of the clamping mechanism (5) has a threaded structure that is locked with the thread (4-1) of the support rod (4); the locking cover plate (5-1) covers the top of the rotatable flange (5-2) of the clamping mechanism (5) and is locked with the threaded holes of the locking cover plate (5-1) and the rotatable flange (5-2) by bolts (5-5); the rotatable flange (5-2) is rotated relative to the structural base (5-4) by adjusting the rotating worm gear angle mechanism (5-3) set on the rotatable flange (5-2).

[0009] In one possible design, the leading edge of the guide vane (3) is provided with a vortex generator (3-1) in the form of two rows of staggered hemispherical protrusions.

[0010] In one possible design, the length of the connecting rod (2) is greater than 3 times the diameter of the test model.

[0011] In one possible design, the support rod (4) is a hollow cylinder with an outer diameter Φ ≤ 1 / 3 of the test model diameter.

[0012] In one possible design, the connecting rod (2) and the support rod (4) are made of 314 stainless steel pipes with a wall thickness ≥ 1 / 5Φ, where Φ is the outer diameter of the steel pipe and the surface roughness Ra ≤ 0.8μm.

[0013] In one possible design, the airfoil (3) has an airfoil aspect ratio of 2.5. The connecting rod (2) and the airfoil (3) are designed separately to facilitate cable insertion. The cable can first pass through the connecting rod, then through the airfoil (3) and the support rod (4). After the cable is inserted, the tail end of the connecting rod (2) is fixed to the airfoil (3) by bolts.

[0014] In one possible design, the air guide vane (3) has a rear cover plate (3-2) to reserve space so that the air guide vane (3) and the tail end of the connecting rod (2) can be fixed by multiple sets of bolts evenly distributed in the circumference. After fixing, the rear cover plate (3-2) is connected to the air guide vane (3) by long bolts (3-3) and then watertight.

[0015] Compared with the prior art, the advantages of this application are: High resistance to deformation: The 314 stainless steel material and thickened design ensure that the deformation of the support structure is less than 0.1mm at a flow rate of 10m / s, thus guaranteeing the positioning accuracy of the model; Minimal flow field interference: The airfoil guide and long connecting rod design reduce the influence area of ​​the support structure on the model wake, so that the flow field near the model is basically unaffected by the support structure when testing the hydrodynamic characteristics of the model. Improved experimental efficiency: Through standardized installation positions and high-precision cornering mechanisms, the angle of attack switching time for a single experiment is ≤5 minutes, and the data repeatability error is ≤5%; Excellent durability: 314 stainless steel has better resistance to chloride ion corrosion than 304 stainless steel, making it suitable for seawater circulating water tunnel environments and extending its service life. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the low-interference tail support system of the water tunnel test model according to a specific embodiment of the present invention; Figure 2 This is a schematic diagram of the L-shaped wing support structure in the low-interference tail support system of the water tunnel test model according to a specific embodiment of the present invention; Figure 3 This is an exploded view of the adjustable angle-of-attack clamping mechanism in the low-interference tail support system of the water tunnel test model according to a specific embodiment of the present invention. Explanation of reference numerals in the attached figures: Detailed Implementation

[0017] The technical solutions provided in this application are further illustrated below with reference to the embodiments.

[0018] Overall, the low-interference tail support system for the water tunnel test model of the present invention includes: a connecting rod, a guide vane, a support rod, an adjustable angle-of-attack clamping mechanism, and a water tunnel cover plate; the connecting rod is used to connect the rotating test model to be tested, and the rotating test model is threaded onto the connecting rod; the connecting rod is inserted into the connecting hole of the guide vane and fixed to the vane by bolts; the support rod is welded to the upper side of the guide vane. A corner mechanism is fixed on one side of the water tunnel cover. The support rod passes through the through holes of the water tunnel cover and the corner mechanism. The top of the corner mechanism is tightened with a locking cover to fix the support rod. The locking cover is then fixed to the corner mechanism with bolts to achieve rigid fixation of the model. The connecting rod, the guide vane, and the through holes inside the support rod together form a built-in sensor cable channel for threading the sensor cables installed in the model, avoiding cable exposure that may interfere with the flow field and ensuring structural integrity. The length of the connecting rod is greater than 3 times the diameter of the model (in this embodiment, the rotating test model is cylindrical), and the airfoil has an aspect ratio of 2.5 to achieve synergistic optimization of model support stiffness and flow field interference suppression.

[0019] like Figure 1 As shown in the figure, as a specific embodiment, the low-interference tail support system of the water tunnel test model of the present invention operates in a high-speed water tunnel, with the incoming flow direction along the model installation direction (i.e., Figure 1 (From left to right in the middle); Signal acquisition: Sensors are installed at the corresponding positions on the model, and cables pass through the hollow channel 2-1 and are connected to the digital acquisition unit; Adjustment method: The angle of attack of the model is adjusted by the corner mechanism 5.

[0020] The support system includes: a connecting rod 2, a guide vane 3, a support rod 4, and an adjustable angle-of-attack clamping mechanism 5 connected in sequence. The connecting rod 2 connects to the rotating test model 1. One end of the connecting rod 2 is rotatably connected to the tail of the rotating test model 1 via a flange. The length L of the connecting rod 2 satisfies L≥3D (where D is the maximum diameter of the rotating test model). The guide vane 3 has a symmetrical airfoil section, for example, NACA0012, with an aspect ratio of 2.5. It is welded and fixed to the support rod 4, which is welded to the guide vane 3. The support rod 4 is hollow, and the interior of the vane 3... The wing plate 3 has a through hole, which is connected to the hole in the support rod 4 for cable routing. As will be mentioned later, after the three components are connected, a through hollow channel 2-1 will be formed for sensor wiring. The outer diameter of the support rod 4 is Φ≤1 / 3D. It is inserted into the through hole of the adjustable angle of attack clamping mechanism 5, which is fixed to the cover plate 6 to form a rigid connection. Each component of the connecting rod 2, wing plate 3 and support rod 4 has a through hollow channel 2-1 in the longitudinal direction. After the three components are connected, a through hollow channel 2-1 will be formed for sensor wiring.

[0021] like Figure 2 As shown in the diagram, the L-shaped guide vane 3 has a supporting structure. The connecting rod 2 and the support rod 4 are made of 314 stainless steel pipes with a wall thickness ≥ 1 / 5Φ, where Φ is the outer diameter of the pipe, and the surface roughness Ra ≤ 0.8μm. A vortex generator 3-1 is installed at the leading edge of the guide vane 3, consisting of two rows of staggered hemispherical protrusions. The diameter of each hemispherical protrusion is 4mm, with a longitudinal spacing of 25mm along the vane, and a set lateral spacing between the two rows. The shape and distribution of the vortex generator 3-1 are based on the fluid boundary layer control requirements at the leading edge of the vane. When fluid flows over a solid surface such as the vane, a boundary layer with a velocity gradient is formed. As the flow distance increases, the boundary layer changes from laminar to turbulent, and even boundary layer separation occurs, generating significant vortex losses, reducing guiding efficiency, and increasing flow-induced vibration and noise. The protruding structure of the vortex generator can actively induce small-scale, stable vortices within the boundary layer. These vortices can entrain high-energy fluid from outside the boundary layer, replenishing boundary layer energy, delaying or suppressing boundary layer separation, reducing flow-induced vibration noise of the airfoil, and minimizing interference from the airfoil on physical quantities such as vibration acceleration, pulsating pressure, and hydrodynamic noise when testing the test specimen. Simultaneously, the hemispherical structure, compared to conical or strip-shaped protrusions, exhibits better fluid flow characteristics, and the absence of sharp edges reduces local stress concentration and flow-induced noise. Combined with the 314 stainless steel material of the steel pipe support structure, it enhances the overall structure's wear and corrosion resistance. The distribution spacing design is verified through fluid simulation to ensure that, within the design flow velocity range, the small vortices generated by each vortex generator can superimpose to form a continuous vortex band, rather than interfering with each other, ultimately achieving the design goal of optimizing the airfoil's hydrodynamic performance.

[0022] The spacing between the two rows of transverse vortex generators 3-1 is a predetermined distance, for example, 10mm. For two staggered rows of hemispherical vortex generators, the design of the transverse spacing must adhere to two core principles: avoiding mutual interference and cancellation of vortices between adjacent rows, ensuring that each protrusion can effectively generate stable small vortices; and matching the hemisphere diameter to 2.5 to 3 times, while simultaneously forming a reasonable aspect ratio with the longitudinal spacing (in this design, the longitudinal spacing is 25mm, the transverse spacing is 10mm, and the aspect ratio is 2.5:1, conforming to the airfoil guide layout. Given a hemisphere diameter of 4mm, taking a design factor of 2.5, the calculated transverse spacing is 10mm, balancing structural compactness and vortex generation efficiency).

[0023] The connecting rod 2 is inserted into the hole on one side of the leading edge of the guide vane 3 and fixedly connected to the main body of the guide vane 3 by the connecting bolt 2-3. The support rod 4 is welded to the upper side of the guide vane 3 so that the channels in the connecting rod 2, the support rod 4 and the guide vane 3 are connected to form a long straight hollow channel 2-1. The inner wall of the hollow channel 2-1 is provided with an insulating bushing 2-2 (material such as nylon) and sealed by an end waterproof sealing ring 2-4 (material such as fluororubber), which is an important feature of waterproofing.

[0024] like Figure 3 As shown in the exploded view of the adjustable angle-of-attack clamping mechanism 5, the adjustable angle-of-attack clamping mechanism 5 includes a rotating locking cover plate 5-1, a rotatable flange 5-2, a worm gear angle mechanism 5-3, a fixed support housing 5-4, and locking bolt groups 5-5 and 5-6. The rotating worm gear angle mechanism 5-3, which is located on the edge side of the rotatable flange 5-2, can drive the support structure and the test model to achieve ±0.1° angle fine adjustment. The clamping mechanism 5 has a structural base 5-4 fixedly connected to the water tunnel cover plate 6; the support rod 4 has a thread 4-1, which is inserted into the guide groove reserved in the water tunnel cover plate 6 and the matching groove at the bottom of the structural base 5-4 of the clamping mechanism 5 to achieve circumferential limiting; the inner ring of the locking cover plate 5-1 of the clamping mechanism 5 has a threaded structure, which is locked with the thread 4-1 of the support rod 4. The locking cover plate 5-1 covers the top of the rotatable flange 5-2 of the clamping mechanism 5 and is locked with the threaded holes of the locking cover plate 5-1 and the rotatable flange 5-2 by bolts 5-5. The rotatable flange 5-2 is rotated relative to the structural base 5-4 by adjusting the rotating worm gear angle mechanism 5-3 set on the rotatable flange 5-2.

[0025] The specific settings, functions, and effects of this embodiment are as follows: (1) Thick-walled hollow cable management design: The support system adopts a thick-walled hollow integrated structure, in which the connecting rod 2 and the support rod 4 have a wall thickness of 7mm and an inner cavity diameter of 10mm, running through the entire support device and providing a concealed cable channel; The inner wall of the hollow channel 2-1 is equipped with a nylon insulating bushing 2-2 to prevent the cable from being damaged by friction with the metal inner wall, and the end waterproof sealing ring 2-4 (made of fluororubber) prevents water seepage. The hollow structure of the connecting rod 2 and the support rod 4 was designed using finite element topology optimization to reduce weight while maintaining a bending stiffness of ≥2×10⁴ N·m. 2 Equivalent to a solid rod; (2) High-rigidity support structure: The connecting rod 2 and the support rod 4 are integrally formed from 314 stainless steel with a thickness of 7mm, a yield strength ≥520MPa, a static stiffness increase of more than 30%, and a dynamic vibration amplitude reduction to within ±0.05mm. The guide vane 3 and the support rod 4 are laser welded together, and the weld strength coefficient is ≥0.9; The support rod 4 is rigidly fixed by the water tunnel cover plate clamping mechanism 5, forming an overall transmission path of "cover plate-support rod-model" to avoid deformation caused by local stress concentration; Support rod 4 has machined threads 4-1, such as Figure 2 As shown, the guide groove reserved in the water tunnel cover plate 6 and the matching groove at the bottom of the corner clamping mechanism 5 are inserted to achieve circumferential limiting. The inner ring of the rotating locking cover plate 5-1 is machined with a thread structure and locked with the thread 4-1 of the support rod 4. It covers the top of the corner mechanism 5 and is locked with the threaded holes of the locking cover plate 5-1 and the rotatable flange 5-2 by four sets of bolts 5-5 evenly distributed around the circumference (assembly gap ≤ 0.02mm). The connecting rod 2 and the wing plate 3 are designed separately to facilitate cable insertion. The cable can first pass through the connecting rod, then through the wing plate 3 and the support rod 4. After the cable is inserted, the tail end of the connecting rod 2 is fixed to the wing plate 3 with bolts. A rear cover plate 3-2 is cut out on one side below the rear edge of the wing plate 3 to leave space for the wing plate and the end of the connecting rod 2 to be fixed by four sets of bolts evenly distributed around the circumference. After fixing, the rear cover plate 3-2 is connected to the wing plate 3 by long bolts 3-3 and then watertight. A through threaded hole is machined on the rear cover plate 3-2, and a matching threaded hole is machined at the corresponding position on the main body of the wing plate 3. During assembly, the long bolts 3-3 are passed through the through threaded hole of the rear cover plate 3-2 and then screwed into the threaded hole of the main body of the wing plate 3. The reliable connection and fixation between the rear cover plate 3-2 and the main body of the wing plate 3 can be achieved by the tightening force of the bolts.

[0026] The corner mechanism 5 uses a set of high-strength internal hexagon bolts 5-6 to vertically fix the mechanism base to the upper surface of the water tunnel cover plate 6. The bolt preload is ≥90 N·m to ensure a rigid connection between the mechanism base and the cover plate. This allows the rotating worm gear corner mechanism 5-3 to rotate the rotatable flange 5-2 relative to the structural base 5-4, enabling the support structure and model to achieve ±0.1° angle fine-tuning.

[0027] (3) Model pose optimization configuration: The deviation between the model's axis and the water tunnel's axis is controlled to a coaxiality deviation of ≤0.5mm. This ensures that the model's axis coincides spatially with the central axis of the water tunnel experimental section, preventing unilateral turbulence caused by axial misalignment during fluid flow and thus affecting the accuracy of experimental data. The distance between the head of the rotating model and the inlet of the working section is specified. l ( l (To accommodate the length of the experimental model), a boundary layer development zone is reserved in the initial section to ensure the model is in a fully developed turbulent region. The tail section is 2 meters from the outlet. lEstablish a pressure recovery buffer zone to prevent the reverse pressure gradient caused by outlet contraction from propagating upstream and interfering with the model wake, and ensure the uniformity of flow velocity in the experimental section; The adjustable angle-of-attack clamping mechanism 5 integrates a high-precision worm gear angle mechanism 5-3 with a rotatable flange 5-2. The angle adjustment resolution reaches 0.1°, which can continuously change the model's angle of attack and lock it in real time, meeting the research needs of multiple working conditions within the range of -15° to +15° angle of attack.

[0028] (4) Airfoil guide design: At the corner of the support rod 4 and the connecting rod 2, a NACA0012 airfoil section guide vane 3 is installed. The airfoil has a span of 0.25m and a chord length of 0.1m. The angle of attack matches the mainstream direction, so that the water flowing through the support structure is laminated. The leading edge of the guide vane 3 is equipped with vortex generators 3-2, which are staggered hemispherical protrusions with a diameter of 4mm and a spacing of 25mm to reduce flow separation. The length of connecting rod 2 is designed to be more than three times the maximum diameter of the model to ensure that the interference zone between the model and the support structure is far away from the core flow field of the test section.

[0029] Through the detailed description of the specific embodiments above, it can be seen that the significant advantages of the present invention are as follows: High resistance to deformation: The 314 stainless steel material and thickened design ensure that the deformation of the support structure is less than 0.1mm at a flow rate of 10m / s, thus guaranteeing the positioning accuracy of the model; Minimal flow field interference: The airfoil guide and long connecting rod design reduce the influence area of ​​the support structure on the model wake, so that the flow field near the model is basically unaffected by the support structure during hydrodynamic testing. Improved experimental efficiency and accuracy: Standardized installation positions and high-precision cornering mechanisms are used, with the high-precision worm gear cornering mechanism 5-3 achieving an angle adjustment resolution of 0.1°. The rotating cornering mechanism 5-3 can quickly switch experimental angles of attack, making the single experimental angle of attack switching time ≤5 minutes. In addition, the support rod 4 is rigidly fixed by the water tunnel cover plate clamping mechanism 5, forming an overall transmission path of "cover plate-support rod-model", avoiding deformation caused by local stress concentration. At the same time, the low flow field interference design of the guide vane further reduces the overall structural flow-induced vibration deformation, thereby ensuring that the random error generated during multiple continuous measurements is reduced, resulting in a data repeatability error ≤5%, which fully meets the experimental accuracy requirements. Excellent durability: 314 stainless steel has better resistance to chloride ion corrosion than 304 stainless steel, making it suitable for seawater circulating water tunnel environments and extending its service life.

[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A low-interference tail support system for a water tunnel test model, characterized in that, include: The connecting rod (2), the guide vane (3), the support rod (4), the adjustable angle of attack clamping mechanism (5), and the water tunnel cover plate (6) are fixedly connected in sequence, wherein: the connecting rod (2) is used to fix the test model (1) to be tested, and one end of the connecting rod (2) is fixedly connected to the tail of the test model (1); The connecting rod (2) is inserted into the hole at the front edge of the guide vane (3) and fixedly connected to the main body of the guide vane (3). The support rod (4) is welded to the upper side of the guide vane (3). The internal channels of the connecting rod (2), the support rod (4) and the guide vane (3) are connected to form a hollow channel (2-1). The support rod (4) is connected to the water tunnel cover plate (6) through the adjustable angle of attack clamping mechanism (5), and the adjustable angle of attack clamping mechanism (5) has a worm gear rotation mechanism (5-3) so that the support rod (4), the guide vane (3) and the connecting rod (2) together with the test model (1) can rotate and adjust the angle.

2. The low-interference tail support system for the water tunnel test model as described in claim 1, characterized in that, The inner wall of the hollow channel (2-1) is provided with an insulating bushing (2-2).

3. The low-interference tail support system for the water tunnel test model as described in claim 1, characterized in that, The connecting rod (2) is used to fix one end of the test model (1) to be tested, and has a sealing ring (2-4) for waterproof sealing.

4. The low-interference tail support system for the water tunnel test model as described in claim 1, characterized in that, The clamping mechanism (5) has a structural base (5-4) fixedly connected to the water tunnel cover plate (6); the support rod (4) has a thread (4-1) and is inserted into the guide groove reserved in the cover plate (6) and the matching groove at the bottom of the structural base (5-4) of the clamping mechanism (5) to achieve circumferential positioning; the inner ring of the locking cover plate (5-1) of the clamping mechanism (5) has a threaded structure and is locked with the thread (4-1) of the support rod (4); the locking cover plate (5-1) covers the top of the rotatable flange (5-2) of the clamping mechanism (5) and is locked with the threaded holes of the locking cover plate (5-1) and the rotatable flange (5-2) by bolts (5-5); the rotatable flange (5-2) is rotated relative to the structural base (5-4) by adjusting the rotating worm gear angle mechanism (5-3) set on the rotatable flange (5-2).

5. The low-interference tail support system for the water tunnel test model as described in claim 1, characterized in that, The leading edge of the guide vane (3) is provided with a vortex generator (3-1), which is a staggered arrangement of two rows of hemispherical protrusions.

6. The low-interference tail support system for the water tunnel test model as described in claim 1, characterized in that, The length of the connecting rod (2) is greater than 3 times the diameter of the test model.

7. The low-interference tail support system for the water tunnel test model as described in claim 1, characterized in that, The support rod (4) is a hollow cylinder with an outer diameter Φ ≤ 1 / 3 of the test model diameter.

8. The low-interference tail support system for the water tunnel test model as described in claim 1, characterized in that, The connecting rod (2) and the support rod (4) are made of 314 stainless steel pipes with a wall thickness ≥1 / 5Φ, where Φ is the outer diameter of the steel pipe and the surface roughness Ra≤0.8μm.

9. The low-interference tail support system for the water tunnel test model as described in claim 1, characterized in that, The airfoil (3) has an airfoil aspect ratio of 2.

5. The connecting rod (2) and the guide vane (3) are designed separately to facilitate cable insertion. The cable can first pass through the connecting rod, then through the guide vane (3) and the support rod (4). After the cable is inserted, the tail end of the connecting rod (2) is fixed to the guide vane (3) by bolts.

10. The low-interference tail support system for the water tunnel test model as described in claim 1, characterized in that, The guide vane (3) has a rear cover plate (3-2) to reserve space so that the guide vane (3) and the tail end of the connecting rod (2) can be fixed by multiple sets of bolts evenly distributed in the circumference. After fixing, the rear cover plate (3-2) is connected to the guide vane (3) by long bolts (3-3) and then watertight treatment is performed.

Images