Train pneumatic drag reduction and wake flow regulation and control device and method based on bionic shark fins

Abstract

The invention belongs to the technical field of high-speed train aerodynamic optimization, and particularly relates to a train pneumatic drag reduction and wake flow regulation and control device and method based on bionic shark fins. The device comprises a base, the base is arranged on the lower surface of the vehicle body fairing through a plurality of bolts, a fin plate is arranged on the base, and a fixing block is arranged at the bottom of the fin plate; the base is provided with a plurality of limiting and locking mechanisms, the fin plate is limited through the limiting and locking mechanisms, the limiting and locking mechanisms are provided with driving mechanisms, the driving mechanisms are connected with rotating shafts, and the rotating shafts are connected with the fixing blocks and used for driving the fin plate to rotate; a lateral reinforcing plate is arranged on the outer side of the base, a pneumatic compensation plate is arranged between the lateral reinforcing plate and the fin plate, and the pneumatic compensation plate is fixedly connected with the base plate. By dynamically adjusting the attack angle and clearance compensation of an additional device on the surface of the vehicle body, aerodynamic resistance is reduced, wake flow stability is improved, and self-adaptive optimization under complex working conditions is achieved.

Description

Technical Field

[0001] This invention belongs to the field of high-speed train aerodynamic optimization technology, specifically relating to a train aerodynamic drag reduction and wake control device and method based on a biomimetic shark fin. Background Technology

[0002] High-speed trains have become a new "image representative" and "diplomatic calling card" for my country, representing a significant breakthrough and a symbol of independent innovation in the country's construction of an innovative nation. The "Outline for Building a Powerful Transportation Nation" explicitly proposes "strengthening energy conservation, emission reduction, and environmental pollution prevention, and scientifically and rationally coordinating scientific and technological reserves research on high-speed rail passenger train systems with speeds of 400 km / h." China's high-speed rail construction is developing towards environmental protection, energy conservation, and higher speeds. With the increase in train speed, some new technological challenges have also emerged, the most prominent being aerodynamics. Train aerodynamic performance is crucial to high-speed train design, including basic aerodynamic characteristics and crosswind aerodynamic characteristics. At high speeds, due to the viscosity of air, high-speed trains drag the surrounding air along the ground, creating a wake behind the train and generating complex vortex structures—a phenomenon known as a wake vortex. The wake of a high-speed train is a highly complex turbulent flow with very high turbulence intensity. Especially in the near-wake region, significant turbulent vortex structures exist. High-speed train wake vortices not only increase air resistance and reduce operating efficiency but may also affect the train's stability and safety. By optimizing train design and improving aerodynamic performance, air resistance can be effectively reduced, thereby enhancing train stability and safety. Such research not only contributes to the further development of high-speed train technology in my country but also to the advancement of high-speed train technology globally.

[0003] As train speeds increase to 400 km / h and above, aerodynamic drag and wake turbulence become core factors limiting energy efficiency and safety. Traditional drag reduction solutions (such as smoothing the car body and using fixed fairings) have the following drawbacks: (1) Fixed structure: It cannot be dynamically adjusted according to real-time operating parameters (speed, crosswind intensity), resulting in limited aerodynamic optimization effect.

[0004] (2) Secondary eddies: The gap between the auxiliary device and the car body causes airflow separation, which intensifies local turbulence. Currently, drag reduction solutions for high-speed trains include smoothing the car body and installing a tail fairing, but these have many limitations in practical applications. Although a smoothing design of the car body can reduce the drag caused by surface roughness, it cannot effectively suppress the separation of high-speed airflow on complex three-dimensional structures. This separation leads to the generation of local eddies, thereby increasing drag.

[0005] (3) The contradiction between weight and reliability: Lightweight design is often accompanied by insufficient stiffness, while high-strength structure increases energy consumption. In order to reduce weight, composite materials are often used to install fairings at the rear of the vehicle body, but their impact resistance is weak, requiring the addition of reinforcing ribs or sacrifice of aerodynamic shape, resulting in a decrease in drag reduction effect.

[0006] The existing technology (such as CN118928484A) features a biomimetic wing plate structure. This design can adjust the pressure difference between the front and back sides of the train. However, this design has problems such as difficulty in coordinating multiple degrees of freedom and insufficient diaphragm strength, which pose safety risks.

[0007] Therefore, there is an urgent need for a comprehensive solution that integrates biomimetic structures, active control, and lightweight materials. This invention proposes a train aerodynamic drag reduction and wake control device and method based on a biomimetic shark fin. Summary of the Invention

[0008] To address the aforementioned technical problems with existing high-speed train aerodynamic accessories, such as their fixed structure and inability to be dynamically adjusted, this invention provides a train aerodynamic drag reduction and wake control device and method based on a biomimetic shark fin. This invention primarily utilizes the synergistic mechanism of dynamic angle-of-attack adjustment and aerodynamic clearance compensation of the biomimetic shark fin structure to improve train operating efficiency and formation safety.

[0009] The technical means employed in this invention are as follows: A train aerodynamic drag reduction and wake control device based on a biomimetic shark fin includes a base, which is mounted on the lower surface of the car body fairing by several bolts. A fin plate is provided on the base, and a fixing block is provided at the bottom of the fin plate. The base is provided with several limiting and locking mechanisms to limit the fin plate. Each limiting and locking mechanism is provided with a driving mechanism, which is connected to a rotating shaft. The rotating shaft is connected to the fixed block to drive the fin plate to rotate. The base is provided with a lateral reinforcement plate around its perimeter, and a pneumatic compensation plate is provided between the lateral reinforcement plate and the fin plate. The pneumatic compensation plate is fixedly connected to the base plate.

[0010] Furthermore, the fin is triangular in shape, the thickness of the fin gradually decreases from the front edge to the rear edge of the fin, and several flow-guiding grooves are provided on the surface of the fin. The fin adopts a composite design of aluminum alloy and carbon fiber reinforcement plate.

[0011] Furthermore, the limiting and locking mechanism includes an electromagnetic base plate, a mechanical limiting pin, and an electromagnetic locking device. The bottom surface of the electromagnetic base plate is connected to the base, the top surface of the electromagnetic base plate is connected to the bottom surface of the mechanical limiting pin, and the top surface of the mechanical limiting pin is connected to the electromagnetic locking device.

[0012] Furthermore, the driving mechanism includes a servo motor drive module and a gear set. The servo motor drive module is mounted on the limit locking mechanism. The servo motor drive module includes a servo motor, and the servo motor drives the rotating shaft through the gear set.

[0013] Furthermore, the device is equipped with a CAN bus communication interface for establishing communication between the device and the train's central system.

[0014] Furthermore, a rubber pad layer is provided between the base and the lower surface of the vehicle body fairing, and the bolt passes through the base, the rubber pad layer and the lower surface of the vehicle body fairing in sequence to achieve a fixed connection between the base, the rubber pad layer and the lower surface of the vehicle body fairing.

[0015] This invention also includes a train aerodynamic drag reduction and wake control method based on a biomimetic shark fin, implemented using the aforementioned train aerodynamic drag reduction and wake control device based on a biomimetic shark fin, comprising the following steps: S1. Keep the fins in the locked position; S2. Collect train speed, crosswind intensity, and train attitude data; S3. If the train speed is less than 200 km / h, keep the fins in the locked position; if the train speed is greater than 200 km / h, execute S4. S4. The train central system calculates the target angle of attack data of the fin based on the algorithm, and transmits the target angle of attack data to the servo motor drive module through the CAN bus; S5. The servo motor drive module acquires the target angle of attack data, drives the fin to the target angle of attack, calculates the gap distance between the aerodynamic compensation plate and the fin based on the target angle of attack data, and adjusts the gap distance between the aerodynamic compensation plate and the fin based on the gap distance.

[0016] Furthermore, the formula for calculating the target angle of attack data is as follows:

[0017] in, For target angle of attack data, For train speed, Crosswind intensity, For train attitude data, As the first weighting coefficient, This is the second weighting coefficient. This is the third weighting coefficient.

[0018] Furthermore, the formula for calculating the gap distance is:

[0019] in, The gap distance, The target angle of attack data.

[0020] Furthermore, the method also includes: S6. The limiting locking mechanism is equipped with a sensor. The limiting locking mechanism monitors the position of the fin plate in real time through the sensor to realize fault safety protection. If the system experiences servo motor over-limit or device failure, the fin plate is forcibly locked; if the system does not experience over-limit or failure, it returns to S2.

[0021] Compared with the prior art, the present invention has the following advantages: This invention achieves multi-dimensional performance improvement through aerodynamic-structural synergistic optimization: under high-speed conditions of 400 km / h, through FLUENT simulation analysis in ANSYS software (using the k-ω turbulence model)... SST (5 million grid points): Compared to the baseline model, the train model equipped with this device (shark fin plate rotation angle of 75°) exhibits a 4.6% reduction in tail car aerodynamic drag and a 2.06% reduction in overall vehicle drag coefficient. Simultaneously, the wake vortex volume is reduced by 25%, and the lateral wind load fluctuation amplitude is suppressed by 5%, significantly improving high-speed stability. In terms of dynamic adaptability, the system switches the angle of attack mode (0°~95°) in real time according to the operating stage (acceleration / cruising). Combined with a hydrophobic-anti-icing composite coating, it reduces rain and snow icing by 60%, enabling stable operation in extreme environments from -40℃ to 80℃, and improving overall energy efficiency by 5%. Regarding lightweighting and reliability, the carbon fiber-aluminum alloy composite topology (interlaminar shear strength ≥120Mpa) reduces weight by 52% compared to traditional steel structures. Combined with dual-motor redundant drive and Hall sensor closed-loop feedback (accuracy ±0.1°), the system failure rate is reduced by 70%, and mechanical locking redundancy design ensures safety in case of failure. The modular design facilitates later maintenance and replacement, meeting the long-term, high-reliability operation requirements of high-speed trains.

[0022] Based on the above reasons, this invention can be widely applied in fields such as high-speed train aerodynamic optimization. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a diagram of the tail vortex trail of the last car of a high-speed train.

[0025] Figure 2 This is a schematic diagram of the overall layout of the train aerodynamic drag reduction and wake control device based on the biomimetic shark fin of the present invention.

[0026] Figure 3 This is a bottom view of the overall layout of the train aerodynamic drag reduction and wake control device based on the biomimetic shark fin of the present invention.

[0027] Figure 4 This is a schematic diagram of the train aerodynamic drag reduction and wake control device based on a biomimetic shark fin according to the present invention.

[0028] Figure 5 This is a front view of the train aerodynamic drag reduction and wake control device based on a biomimetic shark fin according to the present invention.

[0029] Figure 6 This is a top view of the train aerodynamic drag reduction and wake control device based on a biomimetic shark fin according to the present invention.

[0030] Figure 7 This is a side view of the structure of the train aerodynamic drag reduction and wake control device based on the biomimetic shark fin of the present invention.

[0031] Figure 8 This is a side cross-sectional view of the structure of the train aerodynamic drag reduction and wake control device based on a biomimetic shark fin of the present invention when the fin plate is closed.

[0032] Figure 9 This is a side cross-sectional view of the structure of the train aerodynamic drag reduction and wake control device based on a biomimetic shark fin of the present invention when the fin plate is opened.

[0033] Figure 10 This is a front view of the groove structure of the train aerodynamic drag reduction and wake control device based on the biomimetic shark fin of the present invention.

[0034] Figure 11 This is a side view of the groove structure of the train aerodynamic drag reduction and wake control device based on the biomimetic shark fin of the present invention.

[0035] Figure 12 This is a schematic diagram of the transmission mechanism of the train aerodynamic drag reduction and wake control device based on the biomimetic shark fin of the present invention.

[0036] Figure 13 This is a schematic diagram of a train aerodynamic drag reduction and wake control method based on biomimetic shark fin.

[0037] Figure 14 This is a comparison chart of the aerodynamic drag of the entire vehicle.

[0038] Figure 15 A comparison chart of vorticity between high-speed trains equipped with the device of this invention and those without.

[0039] In the diagram: 1. Fin plate; 2. Base; 3. Servo motor drive module; 4. Limit locking mechanism; 5. Pneumatic compensation plate; 6. Lateral reinforcement plate; 7. Rotary shaft; 8. Guide groove; 9. Bolt. Detailed Implementation

[0040] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0043] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0044] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0045] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0046] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0047] like Figure 1 As shown, during high-speed train operation, the low-pressure area formed at the rear of the train undergoes rapid filling under atmospheric influence. At this time, the boundary layer airflow developing along the train body surface, under the combined effect of viscosity and adverse pressure gradient, undergoes boundary layer separation below the nose cone of the rear train. This flow separation process symmetrically generates a pair of high-speed vortices with specific rotational directions on both sides of the nose cone. Based on the above flow field characteristics analysis, the installation position of the biomimetic shark fin drag reduction structure is set in the critical region where the tail vortex begins to separate.

[0048] like Figure 2-3 The location shown is installed on the outer surface below the fairing of the rear car of the high-speed train, and it can be adapted to mainstream models such as CR400AF, CR400BF, and CRH380B.

[0049] like Figure 4-12As shown, this invention provides a train aerodynamic drag reduction and wake control device based on a biomimetic shark fin, including a base 2, which is mounted on the top cover of the vehicle body by several bolts 9. A fin plate 1 is mounted on the base 2, and a fixing block is provided at the bottom of the fin plate 1. The base 2 is equipped with several limiting and locking mechanisms 4, which limit the movement of the fin plate 1. A drive mechanism is provided on each limiting and locking mechanism 4, and the drive mechanism is connected to a rotating shaft 7, which is connected to the fixing block to drive the fin plate 1 to rotate. A lateral reinforcement plate 6 is provided on the outer edge of the base 2, and an aerodynamic compensation plate 5 is provided between the lateral reinforcement plate 6 and the fin plate 1. The aerodynamic compensation plate 5 is fixedly connected to the base plate. The fin plate 1 structure is fixed to the base 2 by the rotating shaft 7 and rotated by a low-speed servo motor. When the biomimetic shark fin fin plate 1 structure is not deployed, it is fixed by the limiting and locking mechanisms. The entire structure is installed below the tail fairing of the high-speed train.

[0050] The fin 1 is triangular in shape, and its thickness gradually decreases from the leading edge to the trailing edge. Several flow-guiding grooves 8 are provided on the surface of the fin 1. The fin 1 is a composite design using aluminum alloy and carbon fiber reinforcement. The carbon fiber reinforcement uses a laminated design with nano-silica reinforcement inserted between the layers, achieving a bending stiffness >1×10⁻⁶. 6 N•m 2 Fin 1 is integrally cast from lightweight aluminum alloy material, featuring a streamlined biomimetic design with a gradually tapering thickness and flow-guiding microgrooves on its surface.

[0051] The optimal drag-reduction dimensions of fin 1 (length 1m, height 0.3m, leading edge angle 14.35°, trailing edge angle 120°) were determined using the response surface methodology. The surface features shark-scale-inspired microgrooves (5mm wide, 2mm deep, evenly distributed on the fin surface with a spacing of 10mm), and the thickness has a gradually tapering structure (20mm at the leading edge, 8mm at the trailing edge). It is made of lightweight aluminum alloy (density <2.8g / cm³). 3 The design incorporates a composite structure with a carbon fiber reinforced plate; the root of the fin plate 1 forms a continuous transition surface with the aerodynamic compensation plate 5, and the compensation gap is dynamically adjustable from 0.5 to 2 mm.

[0052] The base 2 is made of 6061-T6 aluminum alloy integral casting with built-in reinforcing rib structure. It is connected to the vehicle body roof by 4 sets of 35CrMo alloy steel bolts 9. The bolts 9 are diagonally symmetrically distributed with a spacing of 500mm×300mm.

[0053] In a preferred embodiment of the present invention, bolt 9 is an anti-seismic bolt 9 (compliant with GB / T 3098.1 standard).

[0054] The limiting locking mechanism 4 includes an electromagnetic base plate, a mechanical limiting pin, and an electromagnetic locking device. The bottom surface of the electromagnetic base plate is connected to the base 2, the top surface of the electromagnetic base plate is connected to the bottom surface of the mechanical limiting pin, and the top surface of the mechanical limiting pin is connected to the electromagnetic locking device. There are four sets of limiting locking mechanisms 4: two sets are installed beside the edge rotating shaft 7, and two sets are installed beside the servo motor drive module 3. It employs a double safety mechanism of electromagnetic locking device and mechanical limiting pin, and is equipped with a Hall sensor to monitor the position of the fin plate 1 in real time. The locking force is greater than 800N. The Hall sensor monitors positional deviation; if… If the temperature exceeds 1° or the motor current exceeds the limit, the electromagnetic locking reset will be triggered.

[0055] Furthermore, the limit and locking mechanism integrates an overload protection module, which triggers electromagnetic locking and forced reset when the motor current exceeds the threshold or the position deviation of fin 1 is greater than 1°.

[0056] The drive mechanism includes a servo motor drive module 3 and a gear set. The servo motor drive module 3 is mounted on the limit locking mechanism 4. The servo motor drive module 3 includes a redundant configuration of dual low-speed servo motors (rated torque greater than 50 N∙m). The servo motors achieve differential rotation of the fin plate 1 through gear transmission, with a transmission efficiency greater than 92%. The servo motors are equipped with matching planetary reduction gear sets, which are connected to the rotating shaft 7 through the gear set transmission mechanism, achieving a control accuracy of ±0.5°.

[0057] The rotating shaft 7 is a hollow shaft made of 42CrMo alloy steel (50mm in diameter), with self-lubricating bearings at both ends, allowing the biomimetic shark fin plates to rotate within a range of 10°-95°.

[0058] The aerodynamic compensation plate 5 is made of 7075 aviation aluminum alloy. Its curved shape forms a continuous transition with the root of the fin plate 1. It is installed in the gap between the rotating side of the biomimetic shark fin plate 1 and the lateral reinforcement plate 6. The gap compensation amount can be adjusted from 0.5 to 2 mm to reduce the impact of the gap on the aerodynamic effect.

[0059] Lateral reinforcement plate 6 adopts a carbon fiber composite laminate structure. Through topology optimization design, its bending stiffness is greater than 1×10⁻⁶. 6 N m 2 The lateral reinforcement plate 6 is 52% lighter than a steel structure of the same stiffness and forms an airfoil-shaped covering structure with the vehicle body surface. like Figure 8-9 As shown, the pneumatic compensation plate 5 is installed in the gap between the fin plate 1 and the lateral reinforcement plate 6. When the angle of the fin plate 1 changes, the pneumatic compensation plate 5 rotates synchronously to fill the variable gap between the fin plate 1 and the lateral reinforcement plate 6 in real time.

[0060] like Figure 10-11As shown, the portion of fin 1 near the pivot 7 is curved, forming a continuous transition with the aerodynamic compensation plate 5, and its dynamic adjustment response time is less than 0.3 seconds. The surface of fin 1 is provided with equidistant guide grooves 8, which are surface microstructures designed based on biomimetic principles, referencing the dermal groove structure of shark skin. In the aerodynamic optimization device for high-speed trains, this structure actively regulates airflow through precise geometric arrangement, thereby reducing aerodynamic drag, suppressing turbulence, and improving operational stability.

[0061] Furthermore, the device is equipped with a CAN bus (Controller Area Network) communication interface for establishing communication between the device and the train's central system.

[0062] Furthermore, a rubber pad is provided between the base 2 and the lower surface of the vehicle body fairing. The bolt 9 passes through the base 2, the rubber pad and the lower surface of the vehicle body fairing in sequence to achieve a fixed connection between the base 2, the rubber pad and the lower surface of the vehicle body fairing.

[0063] like Figure 12-13 As shown, the present invention also includes a train aerodynamic drag reduction and wake control method based on a biomimetic shark fin, implemented based on the aforementioned train aerodynamic drag reduction and wake control device based on a biomimetic shark fin, characterized by comprising the following steps: S1. Keep fin plate 1 in the locked position.

[0064] S2. The system collects train speed, crosswind intensity, and train attitude data through pressure, attitude, and crosswind sensors.

[0065] S3. If the train speed is less than 200 km / h, keep fin 1 in the locked position; if the train speed is greater than 200 km / h, execute S4.

[0066] S4. The train central system calculates the target angle of attack data of fin 1 based on the algorithm, and transmits the target angle of attack data to the servo motor drive module 3 via the CAN bus.

[0067] The formula for calculating the target angle of attack data is:

[0068] in, For target angle of attack data, For train speed, Crosswind intensity, For train attitude data, As the first weighting coefficient, This is the second weighting coefficient. This is the third weighting coefficient.

[0069] As a preferred embodiment of the present invention, in the above formula... .

[0070] S5. The servo motor drive module 3 acquires the target angle of attack data, drives the fin 1 to the target angle of attack (range of 0° to 95°), and calculates the gap distance between the aerodynamic compensation plate 5 and the fin 1 based on the target angle of attack data to maintain flow field continuity. The gap distance between the aerodynamic compensation plate 5 and the fin 1 is then adjusted based on this gap distance. The formula for calculating the gap distance is:

[0071] in, The gap distance, The target angle of attack data.

[0072] S6. The limit locking mechanism 4 is equipped with a sensor. The limit locking mechanism 4 monitors the position of the fin plate 1 in real time through the sensor to realize fault safety protection. If the servo motor exceeds the limit or the device fails, the fin plate 1 is forcibly locked. If the system does not exceed the limit or fail, it returns to S2 and enters dynamic closed-loop control. The angle is cyclically fine-tuned according to the real-time data, and finally the adaptive optimization of aerodynamic drag and crosswind stability are achieved, forming a synergistic effect mechanism of biomimetic structure and active control.

[0073] The operation of forcibly locking fin plate 1 is as follows: immediately trigger the electromagnetic locking device 4 to forcibly reset.

[0074] like Figure 14 As shown, the aerodynamic performance of this device was verified by FLUENT simulation of a full-size 3D train model (1:1 scale) (with the bionic fish fin plate 1 rotating at an angle of 60°-90°): at an angle of attack of 75° and a speed of 400km / h, the train model with this device installed had the highest drag reduction rate, with the tail car aerodynamic drag decreasing by 4.6% and the whole vehicle aerodynamic drag decreasing by 2.06%.

[0075] like Figure 15 As shown, the biomimetic fish fin structure, through its specific configuration, directionally guides the flow field at the train's rear, promoting an airflow convergence effect in the longitudinal central region. This mechanism effectively suppresses flow field separation on both sides of the nose of the rear car, reducing the wake vortex volume by 25% and thus decreasing aerodynamic drag. The vortex identification method was used here, employing the Q criterion with Q=0.01.

[0076] This invention achieves a 4.6% reduction in aerodynamic drag at the rear of the train, a 2.06% reduction in overall aerodynamic drag, and a 25% reduction in wake vortex volume (based on simulation, train speed 400 km / h, 75° angle of attack). The system integrates dual low-speed servo motor drives, a closed-loop control algorithm, and electromagnetic-mechanical dual protection, making it suitable for energy efficiency optimization of high-speed trains under complex climatic conditions. The system comprises a biomimetic shark fin structure 1, a base 2, a servo motor drive module 3, a limit locking mechanism 4, an aerodynamic compensation plate 5, and a lateral reinforcement plate 6. The fin 1 features a lightweight, streamlined aluminum alloy design with microgrooves on the surface and a 120° trailing edge angle, dynamically adjustable from 0° to 95° angle of attack. The base 2 is rigidly connected to the roof via anti-vibration bolts 9. The drive mechanism is linked to a hollow rotating shaft 7 via a planetary gear set, achieving a control accuracy of ±0.5°. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A train aerodynamic drag reduction and wake control device based on a biomimetic shark fin, characterized in that, Includes a base, which is mounted on the lower surface of the vehicle body fairing by a number of bolts, and a fin is provided on the base, with a fixing block at the bottom of the fin; The base is provided with several limiting and locking mechanisms to limit the fin plate. Each limiting and locking mechanism is provided with a driving mechanism, which is connected to a rotating shaft. The rotating shaft is connected to the fixed block to drive the fin plate to rotate. The base is provided with a lateral reinforcement plate around its perimeter, and a pneumatic compensation plate is provided between the lateral reinforcement plate and the fin plate. The pneumatic compensation plate is fixedly connected to the base plate.

2. The train aerodynamic drag reduction and wake control device based on biomimetic shark fin according to claim 1, characterized in that, The fin is triangular in shape, and its thickness gradually decreases from the front edge to the rear edge. Several flow-guiding grooves are provided on the surface of the fin. The fin is designed with a composite structure of aluminum alloy and carbon fiber reinforcement plate.

3. The train aerodynamic drag reduction and wake control device based on biomimetic shark fin according to claim 1, characterized in that, The limiting and locking mechanism includes an electromagnetic base plate, a mechanical limiting pin, and an electromagnetic locking device. The bottom surface of the electromagnetic base plate is connected to the base, the top surface of the electromagnetic base plate is connected to the bottom surface of the mechanical limiting pin, and the top surface of the mechanical limiting pin is connected to the electromagnetic locking device.

4. The train aerodynamic drag reduction and wake control device based on biomimetic shark fin according to claim 1, characterized in that, The drive mechanism includes a servo motor drive module and a gear set. The servo motor drive module is mounted on the limit locking mechanism. The servo motor drive module includes a servo motor, which drives the rotating shaft through the gear set.

5. The train aerodynamic drag reduction and wake control device based on biomimetic shark fin according to claim 1, characterized in that, The device is equipped with a CAN bus communication interface for establishing communication between the device and the train's central system.

6. The train aerodynamic drag reduction and wake control device based on biomimetic shark fin according to claim 1, characterized in that, A rubber pad is provided between the base and the lower surface of the vehicle body fairing. The bolt passes through the base, the rubber pad and the lower surface of the vehicle body fairing in sequence to achieve a fixed connection between the base, the rubber pad and the lower surface of the vehicle body fairing.

7. A train aerodynamic drag reduction and wake control method based on a biomimetic shark fin, implemented based on the train aerodynamic drag reduction and wake control device based on a biomimetic shark fin as described in claims 1-6, characterized in that, Includes the following steps: S1. Keep the fins in the locked position; S2. Collect train speed, crosswind intensity, and train attitude data; S3. If the train speed is less than 200 km / h, keep the fins in the locked position; if the train speed is greater than 200 km / h, execute S4. S4. The train central system calculates the target angle of attack data of the fin based on the algorithm, and transmits the target angle of attack data to the servo motor drive module through the CAN bus; S5. The servo motor drive module acquires the target angle of attack data, drives the fin to the target angle of attack, calculates the gap distance between the aerodynamic compensation plate and the fin based on the target angle of attack data, and adjusts the gap distance between the aerodynamic compensation plate and the fin based on the gap distance.

8. The train aerodynamic drag reduction and wake control method based on biomimetic shark fin according to claim 7, characterized in that, The formula for calculating the target angle of attack data is: in, For target angle of attack data, For train speed, Crosswind intensity, For train attitude data, As the first weighting coefficient, This is the second weighting coefficient. This is the third weighting coefficient.

9. The train aerodynamic drag reduction and wake control method based on biomimetic shark fin according to claim 7, characterized in that, The formula for calculating the gap distance is: in, The gap distance, The target angle of attack data.

10. The train aerodynamic drag reduction and wake control method based on biomimetic shark fin according to claim 7, characterized in that, The method further includes: S6. The limiting locking mechanism is equipped with a sensor. The limiting locking mechanism monitors the position of the fin plate in real time through the sensor to realize fault safety protection. If the system experiences servo motor over-limit or device failure, the fin plate is forcibly locked; if the system does not experience over-limit or failure, it returns to S2.

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