A biomimetic flow guiding ribbon and a method of designing and processing thereof

Abstract

The present application relates to a kind of bionic flow guiding ribbon and its design and processing method, bionic flow guiding ribbon includes rectangular ribbon base layer and rib sewn on base layer;Several ribs form parallel arrangement of rectangular groove array on the surface of ribbon base layer, and groove direction is parallel to the edge of rectangular ribbon base layer;When ribbon is installed on streamer, groove direction is consistent with the length direction of streamer;In the preparation process of ribbon base layer and ribbon rib, and in the process of composite assembly of ribbon base layer and rib, no adhesive and other processes are used throughout the process, to avoid the increase of overall stiffness of ribbon caused by adhesive curing, which increases resistance;The overall of ribbon uses aramid fiber, which has fine gap, and there is macro energy dissipation in the vibration process under the action of incoming flow, which is beneficial to vibration reduction and noise reduction.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flow guiding ribbons, in particular to a bionic flow guiding ribbon and a design and processing method thereof. BACKGROUND

[0002] As a core technical means for human exploration of marine resources, the performance of deep-sea exploration equipment directly affects the depth and breadth of marine development. The underwater towing system has become a key tool for seabed geological mapping and resource exploration due to its wide range of detection capabilities and high efficiency. The system works through the coordinated operation of the surface towboat, the winch and the tow cable, but it faces a long-standing problem in dynamic operation - the performance degradation of the system caused by tow cable vortex-induced vibration.

[0003] When the towing system travels at high speed underwater, the interaction between the tow cable surface and the water flow forms a complex three-dimensional turbulent flow field. At the micro level, the water flow viscosity and the roughness of the tow cable surface work together to cause high-frequency pulsating pressure in the turbulent boundary layer. This dynamic load formed by micro-scale vortex motion and periodic vortex shedding can cause continuous vibration of the tow cable structure. It is particularly worth noting that even if a smooth tow cable with high-precision processing is used, the vibration phenomenon caused by fluid dynamics cannot be completely eliminated. Long-term vortex-induced vibration not only accelerates the fatigue fracture of the tow cable material, but also significantly reduces the data acquisition accuracy of the underwater sensor, directly affecting the reliability and service life of the entire detection system.

[0004] The current mainstream flow guiding and drag reduction scheme adopts a streamlined flow guiding sleeve design, which achieves the goal of reducing resistance by optimizing the shape of the tow cable. This bionic design can indeed reduce system resistance at the macro level, increase towing speed, and effectively increase the submersion depth of the tow cable. However, in actual application, the rigid structure of the flow guiding sleeve has two defects that are difficult to overcome: first, the additional mass increases the tension at the top of the tow cable, forcing the system to use higher-strength special cable material; second, the fixed clamp is prone to mechanical damage to the tow cable sheath under long-term alternating loads. According to statistical data, the average service life of the tow cable using the traditional flow guiding sleeve is reduced by about 25%.

[0005] To break through the bottleneck of traditional technology, a new type of woven flow guiding belt technology has emerged. This technology implants a woven belt on the surface of the tow cable through a weaving process, making the woven belt and the tow cable form an integral whole, and creating a dynamic adaptive flow field interface. The woven flow guiding belt constructed by this process can form a dynamic buffer interface on the outer surface of the tow cable, converting the high-speed water flow that directly impacts the cable body into tangential flow along the flow guiding layer, effectively isolating the direct impact of the water flow on the tow cable body, reducing the self-noise of the tow cable caused by pulsating pressure, vibration, etc., and also absorbing some vortex-induced vibration energy.

[0006] When the water flow flows through the streamer, the braided fairing disperses the concentrated load into multi-directional stress through micro-deformation, and most of the vibration energy is converted into heat energy dissipation through the frictional damping inside the braided fairing. This energy conversion process not only greatly weakens the transmission of vibration to the streamer body, but also reduces the tension at the top of the streamer by optimizing the flow field distribution, solving the problem of tension surge caused by the structural drag of the traditional fairing. In addition, due to the use of braiding process instead of being fastened on the streamer by friction, the braided fairing can also greatly reduce the friction or extrusion on the outer surface of the streamer, thereby reducing the loss of the streamer when moving underwater.

[0007] However, this innovative technology still has application limitations. The fiber hair type fairing has excellent vibration reduction performance, but it is easy to entangle and knot in complex flow fields, which is inconvenient to use and increases maintenance costs; while the ribbon type design has better flow field adaptability, but due to the relatively low ribbon density, its drag reduction, vibration reduction and noise reduction effect is inferior to the hair form. SUMMARY

[0008] In view of the technical bottleneck that the drag reduction efficiency of the existing braided ribbon is limited, the present application creatively combines the morphological characteristics of shark scale with high-performance materials based on the principle of bionics, and proposes a bionic fairing with composite surface characteristics and its design and processing method. The core innovation lies in: constructing a shark scale groove array on the surface of the traditional rectangular ribbon substrate to form an anisotropic surface structure with flow regulation function.

[0009] The technical scheme of the present application is:

[0010] A bionic fairing, comprising a rectangular ribbon substrate layer and a rib sewn on the substrate layer; a plurality of ribs form a parallel array of rectangular groove arrays on the surface of the ribbon substrate layer, and the groove direction is parallel to the edge of the rectangular ribbon substrate layer; when the ribbon is installed on the streamer, the groove direction is consistent with the length direction of the streamer;

[0011] The length of the ribbon substrate layer is 5 times the diameter of the streamer to be installed; the length-width ratio of the ribbon substrate layer is 1:1; the overall cross-sectional thickness of the ribbon is 1.5mm, the groove width is 3mm, the groove depth is 1mm, and the spacing is 2mm.

[0012] Further, the ribbon substrate layer is obtained by sewing and processing two layers of aramid fiber cloth; the rib is obtained by sewing and processing four layers of aramid fiber cloth; the rib is also fixed on the ribbon substrate layer by sewing process, and does not use glue.

[0013] Further, the length and width of the ribbon substrate layer are both 160mm, and the total number of ribs is 32.

[0014] The design method of the above-mentioned bionic fairing, comprising the following steps:

[0015] Step 1: Basic ribbon length-width ratio optimization design:

[0016] Firstly, the length of the ribbon is determined, which is the size perpendicular to the direction of the streamer, and the corresponding width is the size parallel to the direction of the streamer; taking the diameter of the streamer as the reference size, the width of the ribbon is fixed first, and the length of the ribbon is selected for experiment in different multiples of the diameter of the streamer, and finally the length of the ribbon is determined;

[0017] After determining the length of the ribbon, the initial rectangular plane reference model of the ribbon with different length-width ratios is established by changing the width with the length fixed, and the fluid resistance values corresponding to different length-width ratio configurations are measured under the set flow rate conditions, and the length-width ratio configuration with the minimum fluid resistance value is selected, i.e. 1:1;

[0018] Step 2: Ribbon cross-section thickness optimization design:

[0019] Based on the length-width ratio of the ribbon obtained in step 1, thickness sensitivity analysis is performed: the length-width ratio of the ribbon is fixed, different thickness configurations are established, the fluid resistance values corresponding to different thickness configurations are measured under the set flow rate conditions, and the thickness configuration with the minimum fluid resistance value is selected, i.e. 1.5mm;

[0020] Step 3: Flow field directional installation direction optimization design:

[0021] Based on the optimization design results of steps 1 and 2, a ribbon reference model with a length-width ratio of 1:1 and a thickness of 1.5mm is constructed, and a shark scale groove structure is established on the ribbon reference model, the groove direction is parallel to the edge of the ribbon, the resistance values under different angles between the groove direction and the incoming flow direction are obtained by changing the incoming flow direction, the state of the groove direction parallel to the incoming flow direction is determined when the resistance value is the smallest, and it is ensured that the groove direction is consistent with the length direction of the streamer when the ribbon is installed;

[0022] Step 4: Groove morphology optimization:

[0023] Based on the length-width ratio, overall cross-section thickness and groove direction of the ribbon determined in steps 1-3, and the groove depth is determined to be 1mm, a ribbon with rib strip model with different groove width-depth ratios is established, the corresponding fluid resistance values of different groove width-height ratio configurations are measured under the set flow rate conditions, and the groove width-height ratio configuration with the minimum fluid resistance value is selected, i.e. 3mm:1mm;

[0024] Step 5: Groove distribution density analysis:

[0025] Based on the determination of the groove width and depth in step 4, a ribbon with rib strip model with different groove spacings is established, the corresponding fluid resistance values of different groove width-height ratio configurations are measured under the set flow rate conditions, and the groove spacing is determined to be 2mm in combination with the process cost;

[0026] Step 6: Determine the total number of grooves:

[0027] Given the constraints of a ribbon length of 160mm, a width of 160mm, an overall cross-sectional thickness of 1.5mm, a groove width of 3mm, a depth of 1mm, and a spacing of 2mm, the total number of ribs is determined to be 32.

[0028] The processing method of the above-mentioned biomimetic guide ribbon includes the following steps:

[0029] Step 1: Prepare the ribbon base layer

[0030] The ribbon base layer is constructed using a double-needle bed warp knitting process, and silane coupling agent-modified materials are selected. 49 aramid fiber is orthogonally woven with a warp density of 7.5 yarns / cm and a weft density of 5.8 yarns / cm. A double-layer matrix with a thickness of 0.5 mm is formed by applying a pressure of 0.5 MPa for 15 minutes in a hot-pressing composite process at 120℃.

[0031] Step 2: Prepare the ribbon ribs

[0032] Employing a three-dimensional four-way interlocking weaving process, the fabric is arranged at angles of 0° / 45° / 90° / -45°. 49 aramid fiber, after being formed into a preform, is processed using a femtosecond laser cutting system. Helium gas is introduced during the cutting process to assist in cooling, resulting in rib units with a dimensional tolerance of ±0.04mm.

[0033] Step 3: Assemble the ribbon base layer and ribs together.

[0034] A dynamic tension control system was installed on the STOLL CMS 530 knitting machine. The rib unit obtained in step 2 was sewn onto the ribbon base layer obtained in step 1 at a knitting density of 5.5 needles / cm. A GTX-8 yarn guide was used to achieve 45° cross-layup, ensuring that the deviation angle between the rib axis and the ribbon width direction was ≤0.5°.

[0035] Step 4: Reinforce the edges of the ribbon

[0036] For the fragile edges of the ribbon, ultra-high molecular weight sutures are used to wrap the ribbon three-dimensionally with a high-density three-stitch structure of 8 stitches / cm.

[0037] Step 5: Waterproofing

[0038] The non-ribbed areas of the substrate are pretreated with plasma, and then a PTFE / PDMS / PVP composite coating is deposited by electrospinning.

[0039] The present invention has the following effects:

[0040] The bionic flow guiding ribbon provided by the application does not use gluing process and the like in the preparation process of the ribbon base layer and the ribbon rib and the composite assembly process of the ribbon base layer and the rib, so as to avoid the increase of the overall rigidity of the ribbon and the increase of the resistance caused by the solidification of the glue; the overall ribbon adopts aramid fiber, which has fine gaps and can produce macro energy dissipation in the vibration process under the action of the flow, so as to be beneficial to vibration reduction and noise reduction.

[0041] The application integrates the bionic groove structure into the aramid fiber base through the three-dimensional weaving process, and forms a rigid-flexible coupling integrated flow guiding ribbon structure. The design makes the flow guiding ribbon have the functions of surface drag reduction and structure vibration suppression: the groove structure reduces the fluid resistance by stabilizing the boundary layer flow, and the viscoelasticity of the aramid fiber can absorb 15%-20% of the vibration energy. Experimental data show that, in the flow speed range of 1-5 m / s (Reynolds number Re=2.5x10^4~1.2x10^5), compared with the traditional flow guiding ribbon, the bionic structure of the application reduces the overall resistance of the streamer system by 21%-26%, and the vortex-induced vibration amplitude suppression rate reaches 30%-38%.

[0042] Additional aspects and advantages of the application will be in part apparent and in part pointed out hereinafter in the description of embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0043] The above and / or additional aspects and advantages of the application will become apparent and be readily appreciated from the following description, including the appended drawings.

[0044] Figure 1 : Schematic diagram of bionic drag reduction flow guiding ribbon structure; the top of the figure is the bonding area for fixing the ribbon on the streamer; the shaded part is the rib, and the blank gap is the groove;

[0045] Figure 2 : Partial enlarged view of the side surface of the ribbon;

[0046] Figure 3 : Flow chart of the design method of the ribbon;

[0047] Figure 4 : Flow chart of the processing method of the ribbon DETAILED DESCRIPTION

[0048] Embodiments of the application are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the application, and cannot be understood as a limitation of the application.

[0049] In the description of the present application, it needs to be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0050] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0051] The embodiment is based on the bionic principle. First, a bionic flow guiding ribbon with composite surface characteristics is proposed. A shark scale groove array is constructed on the surface of a traditional rectangular ribbon substrate to form an anisotropic surface structure with flow regulation function.

[0052] The main structural features of the flow guiding ribbon are as follows:

[0053] 1) Surface microstructure: parallel arranged rectangular groove array is formed by precision machining to accurately reproduce the fluid mechanics characteristics of shark scale. In this bionic groove structure, the rib structure leads to flow anisotropy, and the flow is stable along the groove direction, which is beneficial to reduce the fluid flow resistance.

[0054] 2) Cross-section optimization: through the regular arrangement of groove structure, the cross-sectional area of the ribbon is reduced, realizing the synergistic effect of structural drag reduction and morphological drag reduction, and reducing the resistance of the whole streamer when moving underwater;

[0055] 3) Material system: aramid fiber is used as the main material, which has excellent mechanical properties and chemical stability, ensuring the long service life and reliability of the ribbon in complex marine environment.

[0056] Secondly, the design method of the flow guiding ribbon is also proposed in this embodiment. The structure parameters are gradually optimized through multi-dimensional fluid mechanics simulation. The design process includes six key steps, each step verifies the parameter rationality through computational fluid dynamics (CFD) simulation, and the specific implementation is as follows:

[0057] Step 1: optimization design of basic ribbon aspect ratio

[0058] The length of the streamer is determined as the dimension perpendicular to the direction of the streamer, and the corresponding width is the dimension parallel to the direction of the streamer.

[0059] The test finds that the length of the streamer mainly affects the underwater streamer in the following aspects:

[0060] (1) Hydrodynamic effect, including vortex-induced vibration suppression and flow field optimization and resistance balance:

[0061] Vortex-induced vibration suppression: longer streamers can more effectively interfere with the formation of the Karman vortex street behind the streamer, by extending the tangential flow path of the water flow along the streamer, destroying the periodicity of vortex shedding, and reducing the vibration energy input. However, too long a streamer may generate new vortexes due to its own swing, which may even exacerbate local turbulence.

[0062] Flow field optimization and resistance balance: appropriately increasing the length of the streamer can improve the flow guiding effect, convert more longitudinal water flow into tangential flow, reduce the direct impact of the streamer on the flow surface, and thus reduce the overall resistance. However, too long a streamer will increase the added mass and surface friction resistance, which may offset the drag reduction benefit.

[0063] (2) Vibration reduction and noise reduction performance, including energy dissipation efficiency and self-noise suppression:

[0064] Energy dissipation efficiency: long streamers disperse concentrated loads through larger deformation space, and convert more vibration energy into heat energy through fiber friction damping. However, due to the limitation of material strength, there is a critical length threshold.

[0065] Self-noise suppression:

[0066] Longer streamers can more thoroughly isolate the direct effect of water flow pulsating pressure on the streamer body, reducing sensor noise interference. However, if the length exceeds the flow field adaptation range (such as high-speed towing), additional noise may be generated due to the unstable swing of the streamer.

[0067] (3) Structural stability and reliability, including entanglement risk and material fatigue and durability:

[0068] Entanglement risk: in a complex underwater flow field, a too long streamer is more likely to entangle or knot due to flexible deformation, resulting in flow guiding failure and even damage to the streamer.

[0069] Material fatigue and durability: long streamers are more likely to produce stress concentration under alternating loads, accelerating fiber fatigue fracture.

[0070] Therefore, taking the diameter of the tow cable as the reference size, the width of the ribbon unit is first fixed, the length of the ribbon unit with different multiples of the diameter of the tow cable is selected for experiment, and finally the length of the ribbon unit is determined as 5 times the diameter of the tow cable. Compared with the conventional design of taking 8-10 times the diameter of the tow cable as the length of the traditional ribbon unit, the length selection has better effects in terms of vortex-induced vibration suppression and flow field optimization and resistance balance. In the embodiment, the length of the determined ribbon unit is 160 mm.

[0071] After determining the length of the ribbon unit, the aspect ratio of the ribbon unit is further designed. The increase of the aspect ratio (slimness) will reduce the projected area of the incoming flow and reduce the pressure difference resistance, but the surface friction resistance will rise due to the lengthening of the flow path. Therefore, three configurations of aspect ratios 1:1, 2:1 and 3:1 are designed, and the fluid resistance values measured under the flow rate (3.08 m / s) working condition are 3.22 N, 6.548 N and 8.36 N respectively. The data show that the increase of the aspect ratio leads to the increase of the projected area, which is contrary to the groove drag reduction mechanism. Therefore, 1:1 is selected as the optimal aspect ratio.

[0072] Step 2: Optimization design of the thickness of the ribbon section

[0073] On the basis of determining the aspect ratio 1:1 of the ribbon unit, the thickness sensitivity analysis is carried out. Through the analysis, it is found that the main influence of the thickness of the ribbon section on fluid dynamics is reflected in the flow field disturbance and boundary layer control. The boundary layer of the low-thickness ribbon is more likely to adhere, delay flow separation, reduce turbulent kinetic energy in the wake region and reduce pressure difference resistance, but the suppression ability of high-frequency vortex-induced vibration is weak. The high thickness can suppress low-frequency vortex shedding by increasing the disturbance in the wake region and destroying large-scale vortex structure, but early flow separation leads to the rise of pressure difference resistance and may induce secondary vortex flow. On the basis of the analysis, three thickness configurations of 1.5 mm, 2 mm and 2.5 mm are compared, and the corresponding resistance values are 6.548 N, 8.199 N and 9.855 N respectively. The data show that within a certain range, the resistance rises by about 25% with the increase of 0.5 mm of the thickness, so 1.5 mm is selected as the best thickness parameter, which takes into account the processing feasibility and fluid performance.

[0074] Step 3: Optimization design of the installation direction of the flow field

[0075] Based on the optimization design results of step 1 and step 2, a ribbon baseline model with a length-width ratio of 1:1 and a thickness of 1.5 mm is constructed, and a shark-like scale groove structure is established on the baseline model. The groove direction is parallel to the ribbon edge, and the anisotropy characteristics are verified by changing the incoming flow direction. Specifically, the inlet and outlet directions of the water flow are changed to represent the change of the incoming flow direction during simulation. The simulation data shows that when the groove direction is parallel to the incoming flow direction, the resistance is 2.981 N, and when the groove direction is perpendicular to the incoming flow direction, the resistance is 4.314 N, with a difference rate of 44.7%. Therefore, it is determined that the installation direction needs to ensure that the groove direction is strictly aligned with the length direction of the streamer, and the flow guiding effect of the bionic structure is fully played.

[0076] Step 4: Groove morphology optimization

[0077] Steps 1-3 determine the geometric size of the basic ribbon, and then the influence of groove size on resistance is analyzed on the basis of the geometric size of the basic ribbon.

[0078] The groove morphology is mainly characterized by groove depth and width-depth ratio. Through experiments, it is found that shallow grooves with a depth of ≤1 mm can suppress turbulent burst, delay boundary layer separation, and reduce friction resistance, but have limited ability to guide macro-vortex flow and weak vibration reduction effect. Deep grooves with a depth of ≥3 mm can form stable secondary flow channels and force the longitudinal flow to turn into spiral tangential flow, but local vortex flow is easily generated in the grooves, increasing the pressure difference resistance. Since the grooves are formed by sewing the ribs onto the base using aramid fiber, the fluid dynamics effect and processing technology are considered comprehensively. Based on the determination of the ribbon cross-sectional thickness of 1.5 mm in step 2, the final design of the groove depth (i.e. rib height) is set to 1 mm, and the ribbon base layer thickness is 0.5 mm.

[0079] The groove width-depth ratio mainly affects the resistance characteristics. Through experiments, three schemes of width-depth ratio 1mm:1mm, 2mm:1mm, 3mm:1mm are compared, and the measured resistances are 6.397N, 6.352N, 6.193N respectively. It can be seen that as the groove width-depth ratio increases, the resistance of the ribbon gradually decreases, which is due to the increase of the groove width, which further reduces the cross-sectional area of the ribbon in contact with the water flow, consistent with the groove drag reduction mechanism. Finally, 3mm:1mm is selected as the optimal width-height ratio.

[0080] Step 5: Groove distribution density analysis

[0081] The effect of groove spacing on resistance is studied, and the groove spacing is the rib width. Three interval schemes of 1mm, 2mm, 4mm are compared, and the resistance values are 6.193N, 6.185N, 6.168N respectively. The data reveals that although the resistance can be reduced by increasing the interval, the reduction is not more than 0.4%, so based on the cost balance, 2mm is selected as the most economical interval parameter.

[0082] Step 6: Determine the total number of ribs

[0083] Based on the design results from previous steps, parameters such as the geometric dimensions of the ribbon, the geometric dimensions of the grooves, and the spacing between the grooves were determined. Finally, the structural parameters were determined by optimizing the number of grooves. Simulation analysis was performed for the total resistance when the number of grooves was 10, 15, and 20: 6.168 N for 10 grooves, 6.013 N for 15 grooves, and 5.889 N for 20 grooves. It can be seen that increasing the number of grooves leads to a decrease in resistance. This is because the increased number of grooves reduces the cross-sectional area of ​​the ribbon in contact with the incoming flow, consistent with the groove drag reduction mechanism. Based on the constraints of a ribbon unit length of 160 mm, a width of 160 mm, an overall cross-sectional thickness of 1.5 mm, a groove width of 3 mm, a depth of 1 mm, and a spacing of 2 mm, topology optimization calculations determined the total number of grooves to be 32, achieving the optimal balance between structural integrity, process feasibility, and fluid performance.

[0084] This design method, through the aforementioned progressive optimization process, ultimately yields a guide ribbon unit with the following characteristic parameters: overall dimensions of 160mm × 160mm × 1.5mm, groove width of 3mm, depth of 1mm, rib spacing of 2mm, and the groove axis strictly aligned with the tow cable's length direction. Hydrodynamic verification shows that this structure reduces the overall drag of the tow cable system by 29.6% and achieves a vibration energy attenuation rate of 38.2%, significantly improving drag reduction compared to existing guide ribbons.

[0085] Furthermore, this embodiment also provides a processing method for the guide ribbon, and the implementation parameters for each step are determined through orthogonal experiments:

[0086] Step 1: Prepare the ribbon base layer

[0087] The ribbon base layer is constructed using a double-needle bed warp knitting process, and silane coupling agent-modified materials are selected. 49 aramid fiber is orthogonally woven with a warp density of 7.5 yarns / cm and a weft density of 5.8 yarns / cm. A 0.5MPa pressure is applied for 15 minutes in a hot-pressing composite process at 120℃ to form a 0.5mm thick double-layer matrix. Tested according to ASTM D7269 standards, its warp tensile strength reaches 852±12MPa, and its weft tensile strength is 305±8MPa, meeting the stringent requirements of deep-sea high-pressure applications. Three-dimensional topographic scanning shows a surface flatness deviation of less than 0.02mm, significantly reducing the pressure resistance of seawater flowing over the ribbon's base layer surface.

[0088] Step 2: Prepare the ribbon ribs

[0089] Three-dimensional four-way interlocking weaving process is adopted, and the angles are arranged as 0° / 45° / 90° / -45° 49 Aramid fiber (linear density 1680 dtex), after forming the preform, a femtosecond laser cutting system (wavelength 1030 nm, pulse width 350 fs, repetition frequency 200 kHz) is used for processing, and helium is introduced for cooling during the cutting process. Rib units (3.0 mm x 1.0 mm x 175 mm) with a size tolerance of ±0.04 mm are obtained, and SEM detection confirms that there are no carbonization defects in the cut.

[0090] Step 3: Ribbon base layer and rib composite assembly

[0091] A dynamic tension control system is installed on the STOLL CMS 530 knitting machine, and the rib unit obtained in step 2 is sewn on the ribbon base layer obtained in step 1 with a knitting density of 5.5 needles / cm. GTX-8 yarn guide is used to achieve 45° cross-lamination, ensuring that the deviation angle of the rib axis and the ribbon width direction is ≤0.5°.

[0092] Step 4: Strengthening the edges of the ribbon

[0093] For the vulnerable edges of the ribbon, ultra-high molecular weight sutures are used to perform three-dimensional wrapping with a high-density three-thread structure of 8 needles / cm. After the anti-tear test, the edge strength of the treated edge reaches 210 N / cm, which is 65% higher than the conventional hem, while maintaining the overall areal density below 280 g / m 2 After the bending fatigue test, there is no suture fracture or delamination phenomenon.

[0094] Step 5: Waterproof treatment

[0095] The non-rib area of the base layer is pretreated by plasma (power 200 W, time 90 s), and then a PTFE / PDMS / PVP composite coating (ratio 5:3:2) is deposited by electrospinning. After three depositions, the contact angle is 155°±3°, and the rolling angle is ≤5° (referring to ISO 19403-6 standard test). After 100 cycles of 10-30 MPa pressure test, the adhesion retention rate of the coating is 96.2% (verified by ASTM D3359 grid method).

[0096] In the preparation process of the ribbon base layer and the ribbon rib, and the composite assembly process of the ribbon base layer and the ribbon rib, no adhesive or other process is used throughout the process to avoid the increase in overall stiffness of the ribbon caused by the curing of the adhesive, which increases the resistance. The entire ribbon is made of aramid fiber, which has fine gaps, and in the vibration process under the action of the incoming flow, there is macroscopic energy dissipation, which is beneficial to vibration reduction and noise reduction.

[0097] The present application integrates biomimetic groove structure into aramid fiber substrate through three-dimensional weaving process to form a rigid-flexible coupling integrated flow guiding ribbon structure. The design enables the flow guiding ribbon to have both surface drag reduction and structure vibration suppression functions: the groove structure reduces fluid resistance by stabilizing the boundary layer flow, and the viscoelastic properties of aramid fiber can absorb 15%-20% of vibration energy. Experimental data show that, in the flow speed range of 1-5 m / s (Reynolds number Re = 2.5 x 10 4 ~ 1.2 x 10 5 ), compared with the traditional flow guiding ribbon, the biomimetic structure of the present application reduces the overall resistance of the streamer system by 21%-26%, and the vortex-induced vibration amplitude suppression rate reaches 30%-38%.

[0098] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present application, and those of ordinary skill in the art can make changes, modifications, replacements and variations to the above embodiments without departing from the principles and purposes of the present application within the scope of the present application.

Claims

1. A biomimetic guide ribbon, characterized in that: It includes a rectangular ribbon base layer and ribs sewn onto the base layer; several ribs form a parallel array of rectangular grooves on the surface of the ribbon base layer, with the grooves oriented parallel to the edge of the rectangular ribbon base layer; when the ribbon is installed on the tow cable, the grooves are oriented in the same direction as the length of the tow cable. The length of the ribbon base layer is 5 times the diameter of the tow cable to be installed; the length-to-width ratio of the ribbon base layer is 1:1; the overall cross-sectional thickness of the ribbon is 1.5mm, the groove width is 3mm, the groove depth is 1mm, and the spacing is 2mm.

2. The biomimetic guide ribbon according to claim 1, characterized in that: The ribbon base layer is made of two layers of aramid fiber fabric sewn together; the ribs are made of four layers of aramid fiber fabric sewn together; the ribs are also fixed to the ribbon base layer by sewing process, without the use of adhesive.

3. The biomimetic guide ribbon according to claim 2, characterized in that: The ribbon base layer has a length and width of 160mm and a total of 32 ribs.

4. The design method of the biomimetic guide ribbon according to any one of claims 1 to 3, characterized in that: Includes the following steps: Step 1: Optimize the aspect ratio of the basic ribbon: First, determine the length of the ribbon, which is the dimension perpendicular to the direction of the tow cable, and the corresponding width is the dimension parallel to the direction of the tow cable: using the diameter of the tow cable as the reference dimension, first fix the width of the ribbon, select ribbon lengths of different multiples of the tow cable diameter for experiments, and finally determine the length of the ribbon; After determining the length of the ribbon, an initial rectangular planar reference model with different aspect ratios was established by fixing the length and changing the width. The fluid resistance values ​​corresponding to different aspect ratio configurations were measured under the set flow velocity conditions, and the aspect ratio 1:1 configuration with the smallest fluid resistance value was selected. Step 2: Optimization design of ribbon cross-sectional thickness: Based on the ribbon aspect ratio obtained in step 1, a thickness sensitivity analysis is performed: with the ribbon aspect ratio fixed, different thickness configurations are established, and the fluid resistance values ​​corresponding to different thickness configurations are measured under a set flow rate condition. The thickness with the lowest fluid resistance value of 1.5 mm is selected. Step 3: Optimization design of flow field orientation installation: Based on the optimization design results of steps 1 and 2, a ribbon reference model with an aspect ratio of 1:1 and a thickness of 1.5mm is constructed. A shark-scale-like groove structure is built on the ribbon reference model, with the groove direction parallel to the edge of the ribbon. By changing the direction of the incoming flow, the resistance values ​​of the groove direction and the incoming flow direction at different angles are obtained. The state where the groove direction and the incoming flow direction are parallel when the resistance value is the smallest is selected. When installing the ribbon, it is ensured that the groove direction is consistent with the direction of the tow cable length. Step 4: Groove morphology optimization: Based on the ribbon aspect ratio, overall cross-sectional thickness and groove direction determined in steps 1 to 3, and the groove depth determined to be 1 mm, ribbed ribbon models with different groove width-to-depth ratios are established. Under the set flow rate conditions, the corresponding fluid resistance values ​​of different groove width-to-height ratio configurations are measured, and the groove width-to-height ratio configuration with the smallest fluid resistance value of 3 mm:1 mm is selected. Step 5: Groove distribution density analysis: Based on the determination of the groove width and depth in step 4, a ribbed ribbon model with different groove spacing is established. Under the set flow rate conditions, the corresponding fluid resistance values ​​of different groove width-to-height ratio configurations are measured. Combined with the process cost, the groove spacing is determined to be 2mm. Step 6: Determine the total number of grooves: Given the constraints of a ribbon length of 160mm, a width of 160mm, an overall cross-sectional thickness of 1.5mm, a groove width of 3mm, a depth of 1mm, and a spacing of 2mm, the total number of ribs is determined to be 32.

5. The processing method of the biomimetic guide ribbon according to any one of claims 1 to 3, characterized in that: Includes the following steps: Step 1: Prepare the ribbon base layer The ribbon base layer is constructed using a double needle bed warp knitting process. Aramid fibers are selected for orthogonal weaving and then hot-pressed to form a double-layer matrix with a thickness of 0.5mm. Step 2: Prepare the ribbon ribs A three-dimensional four-way interlocking weaving process is adopted, with aramid fibers arranged at angles of 0° / 45° / 90° / -45°. After forming the preform, it is processed by a laser cutting system to obtain rib units with a dimensional tolerance of ±0.04mm. Step 3: Assemble the ribbon base layer and ribs together. The rib unit obtained in step 2 is sewn onto the ribbon base layer obtained in step 1, and the deviation angle between the axial direction of the rib unit and the width direction of the ribbon is ≤0.5°. Step 4: Reinforce the edges of the ribbon To reinforce the fragile edges of the ribbons, a three-dimensional wrapping technique using stitching is employed. Step 5: Waterproofing Plasma pretreatment is performed on the non-ribbed areas of the substrate before depositing a composite waterproof coating.

6. The processing method according to claim 5, characterized in that: The aramid fibers in step 1 are modified with silane coupling agents. The material is 49 aramid fiber, orthogonally woven with a warp density of 7.5 yarns / cm and a weft density of 5.8 yarns / cm, and then subjected to a 0.5MPa pressure for 15 minutes in a hot-pressing composite process at 120℃ to form a double-layer matrix with a thickness of 0.5mm.

7. The processing method according to claim 5, characterized in that: In step 2, a three-dimensional four-way interlocking weaving process is adopted, with four layers arranged and woven at angles of 0° / 45° / 90° / -45°. The 49 aramid fiber is molded into a preform and then processed using a femtosecond laser cutting system. Helium gas is introduced during the cutting process to assist in cooling, resulting in rib units with a dimensional tolerance of ±0.04mm.

8. The processing method according to claim 5, characterized in that: In step 3, the rib unit obtained in step 2 is sewn onto the ribbon base layer obtained in step 1 on a knitting machine with a knitting density of 5.5 needles / cm, and a yarn guide is used to achieve 45° cross-layup to ensure that the deviation angle between the rib axis and the ribbon width direction is ≤0.5°.

9. The processing method according to claim 5, characterized in that: In step 4, ultra-high molecular weight sutures are used to wrap the ribbon in three dimensions with a high-density three-stitch structure of 8 stitches / cm to reinforce the ribbon edge.

10. The processing method according to claim 5, characterized in that: In step 5, the non-ribbed areas of the substrate are subjected to plasma pretreatment, and then a PTFE / PDMS / PVP composite coating is deposited by electrospinning to achieve waterproofing.

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