Bionic flow guide ribbon and design and processing method thereof

Abstract

The invention relates to a bionic flow guide ribbon and a design and processing method thereof. The bionic flow guide ribbon comprises a rectangular ribbon substrate layer and ribs sewn on the substrate layer. The plurality of ribs form a rectangular groove array arranged in parallel on the surface of the ribbon substrate layer, and the groove direction is parallel to the edge of the rectangular ribbon substrate layer; after the ribbon is mounted on the towing cable, the direction of the groove is consistent with the length direction of the towing cable; in the preparation process of the ribbon substrate layer and the ribbon ribs and the composite assembly process of the ribbon substrate layer and the ribs, the processes of gluing and the like are not used in the whole process, and the situation that resistance is increased due to the fact that the overall rigidity of the ribbon is increased after glue curing is avoided; the whole ribbon is made of aramid fibers, fine gaps exist in the ribbon, the macroscopic energy dissipation situation exists in the vibration process generated under the effect of incoming flow, and vibration and noise reduction are facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of guide ribbons, in particular to a bionic guide ribbon and a design and processing method thereof. Background Art

[0002] Deep-sea exploration is a core technological means for human exploration of marine resources, and the performance of its equipment directly impacts the depth and breadth of ocean development. Underwater towed systems, with their wide-area exploration capabilities and efficient operation, have become a key tool for seabed geological mapping and resource exploration. However, these systems, which operate collaboratively with surface tugboats, gaffs, and tow cables, face a long-standing industry challenge during dynamic operations: system performance degradation caused by vortex-induced vibrations in the tow cables.

[0003] When a towing system travels underwater at high speed, the interaction between the towline surface and the water flow forms a complex three-dimensional turbulent field. At the microscopic level, the viscosity of the water flow and the roughness of the towline surface act together to generate high-frequency pulsating pressure within the turbulent boundary layer. This dynamic load, formed by microscale eddy motion and periodic vortex shedding, triggers continuous vibration of the towline structure. It is particularly noteworthy that even with the use of high-precision machined smooth towlines, it is still impossible to completely eliminate this vibration phenomenon caused by the characteristics of the fluid dynamics. Long-term vortex-induced vibration not only accelerates fatigue fracture of the towline material, but also significantly reduces the data acquisition accuracy of underwater sensors, directly affecting the reliability and service life of the entire detection system.

[0004] The current mainstream drag reduction solution uses a streamlined guide sleeve design, which achieves drag reduction by optimizing the towline's profile. This biomimetic design can indeed reduce system resistance at a macro level, increase towing speed, and effectively increase the towline's diving depth. However, in actual application, the rigid structure of the guide sleeve brings two difficult-to-overcome drawbacks: first, the added mass increases tension at the towline's tip, forcing the system to use higher-strength specialty cable materials; second, the fixing clamps are prone to mechanical damage to the towline sheath under long-term alternating loads. According to statistics, the average service life of towlines using traditional guide sleeves is shortened by approximately 25%.

[0005] To overcome the bottlenecks of traditional technologies, a new type of braided flow guide technology has emerged. This technology uses a braided tape implanted onto the surface of the streamer using a weaving process, integrating the tape with the streamer and creating a dynamic, adaptive flow field interface. This braided flow guide, constructed using this process, forms a dynamic buffering interface on the outer surface of the streamer, converting high-speed water flow that would otherwise directly impact the cable into a tangential flow distributed along the flow guide layer. This effectively isolates the direct impact of the water flow on the streamer itself, reduces the self-noise of the streamer caused by pulsating pressure and vibration, and also absorbs a certain amount of vortex-induced vibration energy.

[0006] When water flows through the towline, the braided guide belt disperses the concentrated load into multi-directional stresses through micro-deformation. Most of the vibration energy is converted into heat energy dissipation through friction damping inside the braided guide belt. This energy conversion process not only significantly weakens the transmission of vibration to the towline body, but also reduces the tension at the top of the towline by optimizing the flow field distribution, solving the problem of tension surge caused by structural resistance increase in traditional guide sleeves. In addition, because it is fastened to the towline using a braiding process rather than friction, the braided guide belt can also significantly reduce friction or extrusion on the outer surface of the towline compared to traditional guide sleeves, thereby reducing losses of the towline during underwater movement.

[0007] However, this innovative technology still has limitations. While fiber-hair-type guide strips offer excellent vibration damping performance, they are prone to tangling and knotting in complex flow fields, making them inconvenient to use and increasing maintenance costs. While streamer-type designs offer better flow field adaptability, their relatively low density makes them less effective at reducing drag, vibration, and noise than hair-type designs. Summary of the Invention

[0008] Addressing the technical bottleneck of existing woven streamers that limit drag reduction efficiency, this invention, based on biomimetic principles, creatively integrates the morphological characteristics of shark shield scales with high-performance materials to create a biomimetic flow-guiding streamer with composite surface features and its design and processing methods. Its core innovation lies in constructing a shark shield-like groove array on the surface of a traditional rectangular streamer substrate, creating an anisotropic surface structure with flow control capabilities.

[0009] The technical solution of the present invention is:

[0010] A bionic guide streamer comprises a rectangular streamer base layer and ribs sewn onto the base layer; a plurality of ribs form an array of parallel rectangular grooves on the surface of the streamer base layer, with the grooves oriented parallel to the edges of the rectangular streamer base layer; when the streamer is mounted on a towline, the grooves are oriented in the same direction as the length of the towline;

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

[0012] Furthermore, the ribbon base layer is obtained by sewing two layers of aramid fiber cloth; the ribs are obtained by sewing four layers of aramid fiber cloth; and the ribs are also fixed to the ribbon base layer by sewing without gluing.

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

[0014] The design method of the bionic guide ribbon comprises the following steps:

[0015] Step 1: Optimization design of the aspect ratio of the basic ribbon:

[0016] First, determine the length of the ribbon. The length is the dimension perpendicular to the direction of the towing cable, and the corresponding width is the dimension parallel to the direction of the towing cable. Taking the diameter of the towing cable as the reference dimension, first fix the width of the ribbon, select ribbon lengths with different multiples of the towing cable diameter for experiments, and finally determine the length of the ribbon.

[0017] After determining the length of the ribbon, adopt the method of fixing the length and changing the width to establish an initial rectangular plane reference model of the ribbon with different aspect ratios. Measure the fluid resistance values corresponding to different aspect ratio configurations under the set flow velocity conditions, and select the aspect ratio 1:1 configuration with the minimum fluid resistance value.

[0018] Step 2: Optimization design of the cross-sectional thickness of the ribbon:

[0019] Based on the aspect ratio of the ribbon obtained in Step 1, conduct a thickness sensitivity analysis: fix the aspect ratio of the ribbon, establish different thickness configurations, measure the fluid resistance values corresponding to different thickness configurations under the set flow velocity conditions, and select the thickness 1.5 mm configuration with the minimum fluid resistance value.

[0020] Step 3: Optimization design of the flow field orientation installation direction:

[0021] Based on the optimization design results of Step 1 and Step 2, construct a ribbon reference model with an aspect ratio of 1:1 and a thickness of 1.5 mm, and establish a sharkskin dermal denticle groove structure on the ribbon reference model. The groove direction is parallel to the edge of the ribbon. By changing the incoming flow direction, obtain the resistance values at different angles between the groove direction and the incoming flow direction, and select the state where the groove direction is parallel to the incoming flow direction when the resistance value is the smallest. When installing the ribbon, ensure that the groove direction is consistent with the length direction of the towing cable.

[0022] Step 4: Optimization of the groove morphology:

[0023] Based on the aspect ratio of the ribbon, the overall cross-sectional thickness, and the groove direction determined in Steps 1 to 3, and determine the groove depth to be 1 mm. Establish a ribbed ribbon model with different groove width-depth ratios, measure the fluid resistance values corresponding to different groove width-height ratio configurations under the set flow velocity conditions, and select the groove width-height ratio 3 mm:1 mm configuration with the minimum fluid resistance value.

[0024] Step 5: Analysis of the groove distribution density:

[0025] Based on the groove width and depth determined in Step 4, establish a ribbed ribbon model with different groove spacings, measure the fluid resistance values corresponding to different groove width-height ratio configurations under the set flow velocity conditions, and combine with the process cost to determine the groove spacing to be 2 mm.

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

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

[0028] The above-mentioned method for processing the bionic guide ribbon comprises the following steps:

[0029] Step 1: Prepare the ribbon base layer

[0030] The double needle bed warp knitting process is used to construct the ribbon base layer, and the silane coupling agent modified 49 aramid fibers were 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 was formed by applying a pressure of 0.5 MPa at 120°C for 15 minutes.

[0031] Step 2: Prepare the Ribbon Ribs

[0032] Using three-dimensional four-way interlocking weaving technology, arranged at 0° / 45° / 90° / -45° angles 49 aramid fiber, after being formed into a preform, is processed using a femtosecond laser cutting system. Helium is introduced into the cutting process to assist cooling, and a rib unit with a dimensional tolerance of ±0.04mm is obtained;

[0033] Step 3: Composite assembly of the ribbon base layer and ribs

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

[0035] Step 4: Strengthen the edge of the ribbon

[0036] Aiming at the fragile edge of the ribbon, ultra-high molecular weight suture is used to wrap it three-dimensionally with a high-density three-stitch structure of 8 stitches / cm;

[0037] Step 5: Waterproofing

[0038] The non-ribbed area of the substrate layer was plasma pretreated, and then a PTFE / PDMS / PVP composite coating was deposited by electrospinning.

[0039] The present invention has the following effects:

[0040] In the preparation process of the base layer and ribs of the bionic flow-guiding ribbon proposed by the present invention, as well as in the composite assembly process of the base layer and ribs of the ribbon, adhesive processes are not used throughout the process, avoiding an increase in the overall stiffness of the ribbon caused by the curing of the adhesive and thus increasing the resistance; the entire ribbon is made of aramid fiber, which has fine gaps on its own, and there will be macroscopic energy dissipation during the vibration generated by the oncoming flow, which is beneficial to vibration reduction and noise reduction.

[0041] The present invention integrates a bionic groove structure into the aramid fiber substrate through a three-dimensional braiding process to form a rigid-flexible coupled integrated flow-guiding ribbon structure. This design enables the flow-guiding ribbon to have dual functions of surface drag reduction and structural vibration suppression: the groove structure reduces fluid resistance by stabilizing the boundary layer flow, while the viscoelastic properties of the aramid fiber can absorb 15%-20% of the vibration energy. Experimental data shows that in the flow velocity range of 1-5 m / s (Reynolds number Re = 2.5×10^4 - 1.2×10^5), compared with the traditional flow-guiding ribbon, the bionic structure of the present invention reduces the overall resistance of the tow cable system by 21%-26%, and the suppression rate of the amplitude of vortex-induced vibration reaches 30%-38%.

[0042] The additional aspects and advantages of the present invention will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, where:

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

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

[0046] Figure 3 : Flowchart of the ribbon design method:

[0047] Figure 4 : Flowchart of the ribbon processing method DETAILED DESCRIPTION OF THE EMBODIMENTS

[0048] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present invention, but should not be construed as limiting the present invention.

[0049] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0050] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Therefore, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0051] Based on the bionic principle, this embodiment first proposes a bionic guiding ribbon with composite surface features, constructs a groove array imitating shark dermal denticles on the surface of a traditional rectangular ribbon substrate, and forms an anisotropic surface structure with flow regulation function.

[0052] The main structural features of this guiding ribbon are specifically as follows:

[0053] 1) In terms of surface microstructure, a rectangular groove array arranged in parallel is formed through precision machining to accurately reproduce the hydrodynamic characteristics of shark dermal denticles. In this bionic groove structure, the rib structure results in flow anisotropy, and the flow is stable along the groove direction, which is beneficial to reducing the fluid flow resistance.

[0054] 2) In terms of cross-section optimization, through the regularly arranged 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 suffered by the entire tow cable during underwater movement;

[0055] 3) In terms of the material system, aramid fiber is used as the main material, and its excellent mechanical properties and chemical stability are utilized to ensure that the ribbon has a long service life and reliability in a complex marine environment.

[0056] Secondly, this embodiment also proposes a design method for this guiding ribbon, and gradually optimizes the structural parameters through multi-dimensional hydrodynamic simulations. The design process includes six key steps, and the rationality of the parameters is verified by computational fluid dynamics (CFD) simulations in each step. The specific implementation methods are as follows:

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

[0058] First, the length of the streamer is determined. The length is 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 found that the length of the streamer mainly affects the underwater towline in the following aspects:

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

[0061] Vortex-Induced Vibration Suppression: Longer streamers can more effectively disrupt the formation of Karman vortex streets behind the towline. By extending the tangential flow path along the streamers, they disrupt the periodicity of vortex shedding and reduce vibration energy input. However, excessively long streamers may generate new vortices due to their own oscillation, exacerbating local turbulence.

[0062] Flow field optimization and drag balance: Properly increasing streamer length can improve flow diversion, converting more longitudinal flow into tangential flow, reducing direct impact on the streamer's incoming surface, and thus reducing overall drag. However, excessively long streamers increase added mass and surface friction, potentially offsetting the drag reduction benefits.

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

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

[0065] Self-noise suppression:

[0066] Longer streamers can more thoroughly isolate the direct effects of water flow pulsation on the streamer body, reducing sensor noise interference. However, if the length exceeds the flow field's adaptability (such as when towing at high speeds), the streamer's unstable swing will generate additional noise.

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

[0068] Entanglement risk: In complex underwater flow fields, overly long streamers are more likely to become entangled or knotted due to flexible deformation, resulting in failure of the diversion function or even damage to the towline.

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

[0070] Therefore, taking the cable diameter as the reference dimension, first fix the width of the streamer unit, and select the lengths of the streamer units with different multiples of the cable diameter for experiments. Finally, it is determined that the length of the streamer unit is 5 times the cable diameter. Compared with the conventional design where the length of the traditional streamer unit is 8 - 10 times the cable diameter, this length selection has better effects in both vortex-induced vibration suppression and flow field optimization and drag balance. In this embodiment, the determined length of the streamer unit is 160 mm.

[0071] After determining the length of the streamer unit, further design the aspect ratio of the streamer unit. Increasing the aspect ratio (elongation) will reduce the frontal projected area and lower the pressure drag, but the surface friction drag will increase due to the extended flow path. Therefore, three configurations with aspect ratios of 1:1, 2:1, and 3:1 are designed. The fluid drag values measured under the flow velocity (3.08 m / s) condition are 3.22 N, 6.548 N, and 8.36 N respectively. The data shows that increasing the aspect ratio leads to an increase in the projected area, which contradicts the drag reduction mechanism of the groove. Taking the minimum flow resistance as the goal, the 1:1 aspect ratio is selected as the optimal one.

[0072] Step 2: Optimization design of the streamer cross-section thickness

[0073] Based on the determined aspect ratio of 1:1 of the streamer unit, carry out thickness sensitivity analysis. Through analysis, we find that the main influence of the streamer cross-section thickness in hydrodynamics is reflected in flow field perturbation and boundary layer control. The boundary layer of the low-thickness streamer is more likely to adhere, delaying flow separation, reducing the turbulent kinetic energy in the wake region, and lowering the pressure drag, but its ability to suppress high-frequency vortex-induced vibration is weak. While the high thickness can increase the perturbation in the wake region, destroy the large-scale vortex structure, and suppress low-frequency vortex shedding, but premature flow separation leads to an increase in pressure drag and may induce secondary vortices. Based on this analysis, three thickness configurations of 1.5 mm, 2 mm, and 2.5 mm are compared, and the corresponding drag values are 6.548 N, 8.199 N, and 9.855 N respectively. The data proves that within a certain range, for every 0.5 mm increase in thickness, the drag increases by about 25%. Therefore, 1.5 mm is selected as the best thickness parameter, taking into account both processing feasibility and fluid performance.

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

[0075] Based on the optimized design results of Step 1 and Step 2, a benchmark model of a ribbon with an aspect ratio of 1:1 and a thickness of 1.5 mm was constructed. An artificial shark dermal riblet structure was established on the benchmark model, and the direction of the riblets was parallel to the edge of the ribbon. The anisotropic characteristics were verified by changing the incoming flow direction. Specifically, during the simulation, the change in the incoming flow direction was characterized by changing the inlet and outlet directions of the water flow. The simulation data showed that when the direction of the riblets was parallel to the incoming flow direction, the resistance was 2.981 N, and when the direction of the riblets was perpendicular to the incoming flow direction, the resistance was 4.314 N, with a difference rate of 44.7%. Accordingly, it was determined that the installation direction should ensure that the direction of the riblets is strictly aligned with the direction of the towline length to give full play to the flow guiding effect of the bionic structure.

[0076] Step 4: Optimization of riblet morphology

[0077] Steps 1 to 3 determined the geometric dimensions of the basic ribbon. Next, the influence of the riblet size on the resistance was analyzed on the basic ribbon with determined geometric dimensions.

[0078] The riblet morphology is mainly characterized by the riblet depth and the width-depth ratio. Through experiments, it was found that shallow riblets with a depth ≤ 1 mm can suppress turbulent bursts, delay boundary layer separation, and reduce frictional resistance, but have limited ability to guide macroscopic eddies and weak vibration damping effect; while deep riblets with a depth ≥ 3 mm can form a stable secondary flow channel, forcing the longitudinal water flow to turn into a spiral tangential flow, but local eddies are likely to be generated in the riblets, increasing the pressure drag. Since the riblets are formed by sewing ribs on the substrate using aramid fibers, considering the hydrodynamic effect and the processing technology comprehensively, based on the determination of the ribbon cross-section thickness of 1.5 mm in Step 2, the final designed riblet depth (i.e., the rib height) was set to 1 mm, and the thickness of the ribbon base layer was 0.5 mm.

[0079] The width-depth ratio of the riblets mainly affects the resistance characteristics. By comparing three schemes of width-depth ratios of 1 mm:1 mm, 2 mm:1 mm, and 3 mm:1 mm through experiments, the measured resistances were 6.397 N, 6.352 N, and 6.193 N respectively. It can be seen that as the width-depth ratio of the riblets increases, the resistance received by the ribbon gradually decreases. This is because the increase in the riblet width further reduces the cross-sectional area of the ribbon in contact with the water flow, which conforms to the riblet drag reduction mechanism. Finally, 3 mm:1 mm was selected as the optimal width-height ratio.

[0080] Step 5: Analysis of riblet distribution density

[0081] The influence of the riblet spacing on the resistance was studied. The riblet spacing is the width of the ribs. By comparing three interval schemes of 1 mm, 2 mm, and 4 mm through experiments, the resistance values were 6.193 N, 6.185 N, and 6.168 N respectively. The data revealed that although the increase in the spacing can reduce the resistance, the reduction rate does not exceed 0.4%. Therefore, based on the balance of process costs, 2 mm was selected as the optimal spacing parameter with the best economy.

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

[0083] The geometric dimensions of the ribbon, the geometric dimensions of the grooves, and the spacing of the grooves are determined by the design results of the previous steps, and the structural parameters are finally determined by optimizing the number of grooves. The simulation analysis of the total resistance under three conditions, 10, 15, and 20 grooves, shows that when the number of grooves is 10, the resistance is 6.168N; when the number of grooves is 15, the resistance is 6.013N; and when the number of grooves is 20, the resistance is 5.889N. It can be seen that the increase in the number of grooves leads to a decrease in resistance. This is because the increase in the number of grooves reduces the cross-sectional area of the ribbon in contact with the incoming flow, which is in line with the groove drag reduction mechanism. Based on the constraints of a ribbon unit 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 grooves is determined to be 32 through topological optimization calculations, achieving the best balance between structural integrity, process feasibility, and fluid performance.

[0084] Through the aforementioned progressive optimization process, this design method ultimately resulted in a streamer unit with the following characteristic parameters: overall dimensions of 160mm × 160mm × 1.5mm, a groove width of 3mm, a depth of 1mm, a rib spacing of 2mm, and strict alignment of the groove axis with the length of the streamer. Fluid dynamics verification has shown that this structure can reduce the overall drag of the streamer system by 29.6% and achieve a vibration energy attenuation rate of 38.2%, significantly improving drag reduction compared to existing streamers.

[0085] In addition, this embodiment also provides a method for processing the guide ribbon, and the implementation parameters of each step are determined by orthogonal test optimization:

[0086] Step 1: Prepare the ribbon base layer

[0087] The double needle bed warp knitting process is used to construct the ribbon base layer, and the silane coupling agent modified 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 0.5mm is formed by applying 0.5MPa pressure for 15 minutes at 120°C during a hot press lamination process. Testing according to ASTM D7269 standards demonstrates a warp tensile strength of 852±12MPa and a weft tensile strength of 305±8MPa, meeting the stringent requirements of deep-sea high-pressure applications. 3D topography scans reveal a surface flatness deviation of less than 0.02mm, effectively minimizing the pressure differential resistance of seawater flowing across the ribbon's base layer.

[0088] Step 2: Prepare the Ribbon Ribs

[0089] Using three-dimensional four-way interlocking weaving technology, arranged at 0° / 45° / 90° / -45° angles 49 aramid fiber (linear density 1680 dtex) was formed into a preform and then processed using a femtosecond laser cutting system (wavelength 1030 nm, pulse width 350 fs, repetition rate 200 kHz). Helium was introduced during the cutting process to assist in cooling, and a rib unit (3.0 mm × 1.0 mm × 175 mm) with a dimensional tolerance of ±0.04 mm was obtained. SEM detection confirmed that the incision had no carbonization defects.

[0090] Step 3: Composite assembly of the ribbon base layer and ribs

[0091] A dynamic tension control system was installed on a STOLL CMS 530 braiding machine. The rib units obtained in step 2 were sewn onto the ribbon base layer obtained in step 1 at a weaving density of 5.5 stitches / cm. A GTX-8 yarn guide was used to achieve 45° cross-laying, ensuring that the deviation angle between the rib axis and the ribbon width direction was ≤0.5°.

[0092] Step 4: Strengthen the edge of the ribbon

[0093] For the fragile edges of the ribbon, ultra-high molecular weight suture is used, and a high-density three-stitch structure of 8 stitches / cm is used for three-dimensional wrapping. After tearing resistance testing, the edge strength after treatment reaches 210N / cm, which is 65% higher than that of conventional lock edge, while maintaining the overall surface density below 280g / m 2 After bending fatigue testing, no suture breakage or delamination was observed.

[0094] Step 5: Waterproofing

[0095] The non-ribbed areas of the substrate were plasma pretreated (200 W for 90 seconds), followed by electrospinning of a PTFE / PDMS / PVP composite coating (5:3:2 ratio). After three depositions, the coating achieved a contact angle of 155° ± 3° and a sliding angle of ≤ 5° (tested according to ISO 19403-6). After 100 cycles of pressure testing at 10-30 MPa, the coating demonstrated an adhesion retention of 96.2% (verified by the ASTM D3359 cross-hatch method).

[0096] During the preparation of the ribbon base layer and the ribbon ribs, as well as the composite assembly of the ribbon base layer and the ribs, no gluing or other processes are used throughout the process to avoid an increase in the overall stiffness of the ribbon and increased resistance after the glue solidifies. The entire ribbon is made of aramid fiber, which has fine gaps in it. During the vibration process generated by the incoming flow, there will be macroscopic energy dissipation, which is beneficial to vibration reduction and noise reduction.

[0097] This invention integrates a biomimetic groove structure into an aramid fiber substrate through a three-dimensional weaving process, forming an integrated rigid-flexible coupled guide ribbon structure. This design enables the guide ribbon to simultaneously perform both surface drag reduction and structural vibration suppression: the groove structure reduces fluid resistance by stabilizing boundary layer flow, while the viscoelastic properties of the aramid fiber can absorb 15%-20% of vibration energy. Experimental data show that within the flow velocity range of 1-5 m / s (Reynolds number Re = 2.5×10 4 ~1.2×10 5 ), compared with traditional guide streamers, the bionic structure of the present invention reduces the overall resistance of the towline system by 21%-26%, and the vortex-induced vibration amplitude suppression rate reaches 30%-38%.

[0098] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A bionic diversion ribbon, characterized in that: It includes a rectangular ribbon base layer and ribs sewn on the base layer; a number of ribs form a rectangular groove array arranged in parallel on the surface of the ribbon base layer, and the groove direction is parallel to the edge of the rectangular ribbon base layer; when the ribbon is installed on the tow cable, the groove direction is consistent with the length direction of the tow cable. The length of the ribbon base layer is 5 times the diameter of the tow cable to be installed; the aspect ratio of the length to the width of the ribbon base layer is 1:1; the overall cross-sectional thickness of the ribbon is 1.5 mm, the groove width is 3 mm, the groove depth is 1 mm, and the spacing is 2 mm.

2. The bionic diversion streamer according to claim 1, characterized in that: The ribbon base layer is obtained by sewing and processing two layers of aramid fiber cloth; the ribs are obtained by sewing and processing four layers of aramid fiber cloth; the ribs are also fixed on the ribbon base layer by a sewing process and do not use an adhesive process.

3. The bionic flow guiding ribbon according to claim 2, characterized in that: The length and width of the ribbon base layer are both 160 mm, and the total number of ribs is 32.

4. The design method of the bionic diversion ribbon according to any one of claims 1 to 3, characterized in that: It includes the following steps: Step 1: Optimization design of the aspect ratio of the basic ribbon: First, determine the length of the ribbon, which is the dimension perpendicular to the tow cable direction, and the corresponding width is the dimension parallel to the tow cable direction: taking the tow cable diameter as the reference dimension, first fix the ribbon width, select ribbon lengths of different multiples of the tow cable diameter for experiments, and finally determine the ribbon length. After determining the ribbon length, use the method of fixing the length and changing the width to establish an initial rectangular plane reference model of the ribbon with different aspect ratios, measure the fluid resistance values corresponding to different aspect ratio configurations under the set flow velocity conditions, and select the aspect ratio 1:1 configuration with the minimum fluid resistance value. Step 2: Optimization design of the cross-sectional thickness of the ribbon: Based on the aspect ratio of the ribbon obtained in Step 1, conduct a thickness sensitivity analysis: fix the aspect ratio of the ribbon, establish different thickness configurations, measure the fluid resistance values corresponding to different thickness configurations under the set flow velocity conditions, and select the thickness of 1.5 mm with the minimum fluid resistance value. Step 3: Optimization design of the flow field directional installation direction: Based on the optimization design results of Step 1 and Step 2, construct a ribbon reference model with an aspect ratio of 1:1 and a thickness of 1.5 mm, and establish a shark-scale-like groove structure on the ribbon reference model, with the groove direction parallel to the edge of the ribbon. By changing the oncoming flow direction, obtain the resistance values at different angles between the groove direction and the oncoming flow direction, and select the state where the groove direction is parallel to the oncoming flow direction when the resistance value is the smallest, and determine that when installing the ribbon, ensure that the groove direction is consistent with the length direction of the tow cable. Step 4: Optimization of the groove morphology: Based on the aspect ratio of the ribbon, the overall cross-sectional thickness, and the groove direction determined in Steps 1 to 3, and determine the groove depth to be 1 mm, establish a ribbed ribbon model with different groove width-depth ratios, measure the corresponding fluid resistance values of different groove width-height ratio configurations under the set flow velocity conditions, and select the groove width-height ratio of 3 mm:1 mm configuration with the minimum fluid resistance value. Step 5: Analysis of the groove distribution density: Based on the groove width and depth determined in Step 4, establish a ribbed ribbon model with different groove spacings, measure the corresponding fluid resistance values of different groove width-height ratio configurations under the set flow velocity conditions, and combine the process cost to determine the groove spacing to be 2 mm. Step 6: Determine the total number of grooves: Based on the constraints that the length of the ribbon is 160 mm, the width is 160 mm, the overall cross-sectional thickness is 1.5 mm, the groove width is 3 mm, the depth is 1 mm, and the spacing is 2 mm, the total number of ribs is determined to be 32.

5. The processing method of the bionic diversion ribbon according to any one of claims 1 to 3, characterized in that: It includes the following steps: Step 1: Prepare the ribbon base layer Construct the ribbon base layer using a double needle bed warp knitting process. Select aramid fibers for orthogonal knitting and form a double-layer matrix with a thickness of 0.5 mm after hot pressing. Step 2: Prepare the ribbon ribs Adopt a three-dimensional four-directional interlock knitting process to arrange and knit aramid fibers at angles of 0° / 45° / 90° / -45°. After forming the preform, use a laser cutting system for processing to obtain rib units with a dimensional tolerance of ±0.04 mm. Step 3: Composite assembly of the ribbon base layer and the ribs Sew the rib units obtained in Step 2 onto the ribbon base layer obtained in Step 1, and the deviation angle between the axial direction of the rib units and the width direction of the ribbon ≤ 0.5°. Step 4: Strengthen the ribbon edge For the vulnerable edges of the ribbon, use stitches for three-dimensional wrapping to strengthen the ribbon edge. Step 5: Waterproof treatment Perform plasma pretreatment on the non-rib area of the base layer and then deposit a composite waterproof coating.

6. The processing method according to claim 5, characterized in that: The aramid fiber in Step 1 is the 49 aramid fiber modified by a silane coupling agent, and orthogonal weaving is carried out with a warp density of 7.5 roots / cm and a weft density of 5.8 roots / cm, and a pressure of 0.5 MPa is applied for 15 minutes in a hot pressing composite process at 120 °C to form a double-layer matrix with a thickness of 0.5 mm.

7. The processing method according to claim 5, wherein: In Step 2, a three-dimensional four-way interlock weaving process is adopted to weave four layers at angles of 0° / 45° / 90° / -45° with 49 aramid fibers. After forming the preform, it is processed using a femtosecond laser cutting system, and helium is introduced during the cutting process for auxiliary cooling to obtain rib units with a dimensional tolerance of ±0.04 mm.

8. The processing method according to claim 5, characterized in that: In Step 3, sew the rib units obtained in Step 2 onto the ribbon base layer obtained in Step 1 on a knitting machine with a dynamic tension control system at a knitting density of 5.5 stitches / cm, and use a yarn guide to achieve 45° cross-laying to ensure that the deviation angle between the axial direction of the ribs and the width direction of the ribbon ≤ 0.5°.

9. The processing method according to claim 5, characterized in that: In Step 4, use ultra-high molecular weight stitches and perform three-dimensional wrapping with a high-density three-thread stitch structure of 8 stitches / cm to strengthen the ribbon edge.

10. The processing method according to claim 5, characterized in that: In Step 5, perform plasma pretreatment on the non-rib area of the base layer and then achieve waterproof treatment by electrostatic spinning and depositing a PTFE / PDMS / PVP composite coating.

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