Steel-frame bobsled drag reduction suit

Abstract

The present application relates to the technical field of sports equipment and clothing design, and more particularly to a steel frame bobsled drag reduction racing suit, which is divided into the following zones: easy separation zone: located at the shoulder-blade outer edge, waist-hip transition and inner arm, the wall shear stress τ w ≤1.2Pa and pressure gradient p>0.05Pa / mm; flow attachment zone: located at the chest-abdomen front midline, back main area and thigh-calf front side, the wall shear stress τ w ≥1.2Pa, pressure gradient p≤0.05Pa / mm and surface curvature κ≤0.08mm ‑1 ; dynamic deformation zone: located at the knee front annular band and hip lower area, the angular acceleration >1500° / s² and the curvature change rate Δκ / Δt>0.15mm ‑1 in the motion stage. The present application solves the problems of high pressure difference resistance ratio, large suture interference, poor dynamic zone adaptation and insufficient mass production feasibility under the existing high-speed sliding conditions, and the average drag coefficient Cd is reduced by 3.2%-5.0% compared with the non-zoned scheme.

Description

Technical Field

[0001] This invention relates to the field of sports equipment and clothing design technology, and in particular to a drag-reducing racing suit for steel-framed bobsleighs. Background Technology

[0002] Skeleton is a high-speed winter racing sport involving prone gliding. Athletes glide along an ice track with their heads forward and torsos pressed against the sled, reaching speeds exceeding 130 km / h. Within this speed range, the surface area facing the airflow is large, and the boundary layer on the body surface is fully developed. Aerodynamic drag accounts for over 80% of the total drag, with pressure drag accounting for ≥86% and friction drag accounting for approximately 12%–14%. As the direct interface between the human body and the airflow, the aerodynamic performance of the racing suit has a decisive impact on the competition results.

[0003] Existing skeleton racing suits mostly use single-density elastic knitted fabrics or simple spliced ​​structures. The surface roughness, seam direction, and local stiffness distribution of the fabric are not systematically optimized for the three-dimensional flow field characteristics under prone gliding postures. Some solutions only use high-smoothness yarns in the surface fabric to reduce frictional drag, without implementing active boundary layer control in the main pressure drag control areas, such as the shoulders, outer edge of the scapula, and waist-hip transition zone. This causes the airflow to separate prematurely at locations of abrupt curvature changes, forming large-scale low-pressure wakes and limiting the overall drag reduction potential.

[0004] Furthermore, traditional racing suits often feature horizontal or circumferential seams, with the seam protrusions approximately 2-3 times the fabric thickness. This creates periodic disturbance sources within the high-speed boundary layer, inducing localized vortex streets and additional pressure fluctuations. Additionally, the central vertical seam on the back lacks a sealing mechanism, allowing airflow infiltration to increase the boundary layer thickness and further amplify shape drag. Dynamic deformation areas such as the knees and below the hips suffer from insufficient fabric elasticity, leading to localized wrinkles during the push-car phase at the start, causing instantaneous flow separation and a surge in uncontrollable drag.

[0005] In summary, existing steel-frame bobsleigh racing suits have the following deficiencies in terms of the matching of "fabric-structure-function": a. The fabric does not distinguish between the downstream adhesion zone, the easy separation zone, and the dynamic deformation zone, resulting in a single function. b. The direction of the suture line is perpendicular or oblique to the mainstream direction, and local flow interference is significant; c. Lack of integrated design for active excitation and flow guidance of the boundary layer, unable to suppress curvature-induced separation; d. The fabric stiffness and elasticity in the dynamic zone are unbalanced, resulting in insufficient coordination between aerodynamic and motion functions.

[0006] Therefore, there is an urgent need for a drag-reducing racing suit for steel-framed bobsleighs based on the integrated flow field characteristics of "human-vehicle". Through a zoned fabric system, streamlined structural line layout and integrated design of local micro-scale turbulence / guide, it is possible to achieve a synergistic improvement in high boundary layer stability, low pressure drag and excellent dynamic adaptability, thereby breaking through the existing technical bottlenecks. Summary of the Invention

[0007] Based on the above analysis, the present invention aims to provide a steel-frame bobsleigh drag-reducing racing suit, which solves at least one of the problems existing in the prior art, such as high pressure drag ratio under high-speed skiing conditions, large stitching interference, poor dynamic zone adaptation, and insufficient mass production feasibility.

[0008] The objective of this invention is mainly achieved through the following technical solutions: A skeleton racing suit for reducing drag, the suit covering all areas of the human body except the face, and divided into sections as follows: Easily separable zones: located at the outer edge of the shoulder-scapula, the transition between the waist and hip, and the inner side of the arm. In CFD simulation, the wall shear stress τ in these easily separable zones... w <1.2 Pa and pressure gradient p > 0.05 Pa / mm; The downstream attachment zone is located along the anterior midline of the chest and abdomen, the main back region, and the anterior aspect of the thigh and calf. In CFD simulation, the wall shear stress τ in this downstream attachment zone is... w ≥1.2Pa, pressure gradient p≤0.05Pa / mm and surface curvature κ≤0.08mm -1 ; Dynamic deformation zone: located in the anterior knee ring and under the buttocks region, where the angular acceleration during movement is >1500° / s² and the rate of curvature change Δκ / Δt is >0.15mm. -1 .

[0009] Preferably, the easily separable area includes the shoulder-scapula outer edge region, the waist-hip transition region, and the inner arm region; Shoulder - outer edge of scapula region: a band-shaped area 20mm lateral to the line connecting the lateral neck point to the acromion and the inferior angle of the scapula; The transition zone between the waist and hips: the area from the lower edge of the iliac crest to the upper bundle of the gluteus maximus and the 15mm inner side of the starting line of the posterolateral thigh. Inner arm region: the area 10 mm anterior to the line connecting the axillary point to the medial condyle of the humerus and the styloid process of the ulna.

[0010] Preferably, a guide rib structure extending in parallel with the airflow direction is provided in the shoulder-scapular outer edge region.

[0011] Preferably, the downstream attachment area includes the anterior midline region of the chest and abdomen, the main region of the back, and the anterior region of the thigh and calf. The anterior midline region of the chest and abdomen: from the lower border of the clavicle to the xiphoid process and the surface of the pubic symphysis; Main back region: from the spinous process of the 7th cervical vertebra to the lumbosacral junction and 5 mm above the gluteal cleft; Front thigh-lower leg region: a 20mm band within the line connecting the anterior superior iliac spine to the upper border of the patella and the lateral border of the tibialis anterior muscle.

[0012] Preferably, the main area on the back is provided with a regularly arranged spoiler protrusion structure.

[0013] Preferably, the co-current attachment zone and the easily separable zone are three-layer composite structures, including an outer fabric layer, an inner fabric layer, and a polymer film layer disposed between the two.

[0014] Preferably, the outer and inner fabric layers of the downstream attachment zone and the outer fabric layer of the easily separable zone are all made of high-density elastic knitting with a surface density of 150g / m²~180g / m², a thickness of 0.3mm~0.5mm, and an elongation of ≥120%.

[0015] Preferably, the inner fabric layer of the easily separable zone is a recessed area or longitudinal grooves.

[0016] Preferably, the dynamic deformation zone includes the anterior knee ring area and the lower hip area; Anterior circumferential band region: a band extending from 60mm above the upper edge of the patella to 50mm below the lower edge of the patella; The area below the buttocks: the area from the ischial tuberosity to the transverse gluteal crease and the 25mm area inside the posterior thigh fold.

[0017] Preferably, the dynamic deformation zone is a single-layer four-way stretch fabric structure with a longitudinal breaking elongation ≥150%, a transverse breaking elongation ≥180%, and a recovery rate ≥95%.

[0018] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: (1) This invention adopts a functional zoning design. In the downstream attachment zone, a composite structure with high-density elastic knitted fabrics for both the surface and bottom layers is used. In the easily separable zone, a differentiated configuration is introduced with a smooth surface and a bottom layer with regular textures (pits or grooves). Wind tunnel experiments show that in the high-speed gliding range of 25m / s to 35m / s, the average drag coefficient Cd is reduced by 3.2% to 5.0% compared to the unzoning scheme, and the slope of Cd with increasing wind speed decreases by 42%, directly achieving effective suppression of high-proportion pressure difference drag.

[0019] (2) This invention utilizes a streamlined structural line layout, arranging the main seam along the dominant airflow direction to avoid high-shear, easily detached areas such as the back of the legs and the outer back of the arms. A low-thickness edge-sealing technique is employed to control the seam thickness to within 1.2–1.5 times the thickness of the adjacent fabric. A heat-bonded TPU windproof strip (10mm wide, 0.2mm thick) is added to the inner side of the vertical structural line in the center of the back, significantly reducing the interference of the seam protrusions on the boundary layer. Test results show that the velocity loss rate in the main back area decreased by 0.8%, the surface roughness Ra decreased from 12µm to 4µm, and the airflow permeability in the seam area decreased to 0mL / (cm²·s), effectively suppressing local vortex streets and pressure fluctuations, achieving a "seamless" effect.

[0020] (3) By setting flexible silicone / TPE guide ribs (0.5 mm high, 6 mm spacing, and angle ≤15° with the mainstream direction) on the shoulder, the present invention shows that the structure extends the reattachment length of the boundary layer in the shoulder-back transition zone by 18 mm, reduces the airflow separation angle from 22° to 14°, reduces the lateral flow velocity in the high-pressure zone of the shoulder by 11%, and reduces the tail vortex intensity by 19%. By arranging a turbulence protrusion array (4 mm in diameter, 0.5 mm high, 10 mm center-to-center distance, and densely arranged in triangles or hexagons) in the outer edge region of the scapula, the flow separation line in the curvature change zone of the back is successfully moved down by about 40 mm, and the Cd value is further reduced by 0.010 at a wind speed of 35 m / s.

[0021] (4) The present invention uses a four-way stretch knitted fabric in the area in front of the knee and below the buttocks, with a longitudinal breaking elongation ≥150%, a transverse elongation ≥180%, and a recovery rate ≥95%. Under the instantaneous tensile condition of 3.5kN / m, the surface ripple height is <0.2mm, and the additional resistance fluctuation during the starting phase is <0.3N. It takes into account both the degree of freedom required for large-amplitude flexion and extension movements and the close fit and wrinkle-free performance during high-speed gliding, and solves the problem that traditional high-modulus fabrics are prone to wrinkling in the dynamic area and induce instantaneous flow separation.

[0022] (5) In this invention, both the guide ribs and the turbulence protrusions are integrally formed by hot pressing-hot pressing-in-mold injection molding or 3D printing. In particular, the 3D printing step length is controlled to keep the dimensional tolerance within ±0.05mm. Wind tunnel testing of 200 sets of finished garments in the same batch showed that the standard deviation of the drag coefficient Cd σ≤0.003, meeting the consistency requirements of national team-level equipment, and fully verifying the reproducibility and stability of the technical solution of this application on an industrial scale.

[0023] Other features and advantages of the invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained from the embodiments described and the accompanying drawings. Attached Figure Description

[0024] Figure 1 This is a frontal view schematic diagram of the finished suture solution in an embodiment of the present invention.

[0025] Figure 2 This is a schematic diagram of the finished suture solution from the back view in an embodiment of the present invention.

[0026] Figure 3 This is a schematic diagram of the flow-guiding rib structure and the turbulence-disrupting protrusion structure in an embodiment of the present invention.

[0027] Figure 4 This is a schematic diagram of the area where the flow-guiding rib structure and the turbulence-disrupting protrusion structure are set in an embodiment of the present invention.

[0028] Figure 5 The data provided are the drag coefficient test data for the embodiments and comparative examples of this invention. Detailed Implementation

[0029] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the present invention.

[0030] On one hand, this invention discloses a skeleton racing suit that reduces drag on a bobsleigh, the suit covering all areas of the human body except the face, and divided into sections as follows: Easily separable zones: located at the outer edge of the shoulder-scapula, the transition between the waist and hip, and the inner side of the arm. In CFD simulation, the wall shear stress τ in these easily separable zones... w <1.2 Pa and pressure gradient p > 0.05 Pa / mm; The downstream attachment zone is located along the anterior midline of the chest and abdomen, the main back region, and the anterior aspect of the thigh and calf. In CFD simulation, the wall shear stress τ in this downstream attachment zone is... w ≥1.2Pa, pressure gradient p≤0.05Pa / mm and surface curvature κ≤0.08mm -1 ; Dynamic deformation zone: located in the anterior knee ring and under the buttocks region, where the angular acceleration during movement is >1500° / s² and the rate of curvature change Δκ / Δt is >0.15mm. -1 .

[0031] Compared with existing technologies, this invention adopts a functional zoning design. In the downstream attachment zone, a composite structure with high-density elastic knitted fabrics for both the top and bottom layers is used. In the easily separable zone, a differentiated configuration is introduced, with a smooth top layer and a bottom layer with regular textures (pits or grooves). Wind tunnel experiments show that in the high-speed gliding range of 25m / s to 35m / s, the average drag coefficient Cd is reduced by 3.2% to 5.0% compared to the unzoning scheme, and the slope of Cd with increasing wind speed decreases by 42%, directly achieving effective suppression of high-proportion pressure drag.

[0032] Specifically, the easily separable areas include the shoulder-scapular outer edge region, the waist-hip transition region, and the inner arm region; Shoulder - outer edge of scapula region: a band-shaped area 20mm lateral to the line connecting the lateral neck point to the acromion and the inferior angle of the scapula; The transition zone between the waist and hips: the area from the lower edge of the iliac crest to the upper bundle of the gluteus maximus and the 15mm inner side of the starting line of the posterolateral thigh. Inner arm region: the area 10 mm anterior to the line connecting the axillary point to the medial condyle of the humerus and the styloid process of the ulna.

[0033] Specifically, the downstream attachment area includes the anterior midline region of the chest and abdomen, the main back region, and the anterior thigh-lower leg region; The anterior midline region of the chest and abdomen: from the lower border of the clavicle to the xiphoid process and the surface of the pubic symphysis; Main back region: from the spinous process of the 7th cervical vertebra to the lumbosacral junction and 5 mm above the gluteal cleft; Front thigh-lower leg region: a 20mm band within the line connecting the anterior superior iliac spine to the upper border of the patella and the lateral border of the tibialis anterior muscle.

[0034] Specifically, the dynamic deformation zone includes the anterior knee ring area and the lower hip area; Anterior circumferential band region: a band extending from 60mm above the upper edge of the patella to 50mm below the lower edge of the patella; The area below the buttocks: the area from the ischial tuberosity to the transverse gluteal crease and the 25mm area inside the posterior thigh fold.

[0035] Specifically, the downstream attachment area has a three-layer composite structure, including an outer fabric layer, an inner fabric layer, and a polymer film layer disposed between the two; Both the outer and inner fabric layers of the downstream attachment zone are made of high-density elastic knitting, with a areal density of 150g / m²~180g / m², a thickness of 0.3mm~0.5mm, and an elongation of ≥120%. The polymer film layer is an airtight polyurethane film, such as thermoplastic polyurethane (TPU) film material, with a thickness of 20μm~30μm, a tensile strength of not less than 30MPa, and an elongation at break of greater than 400%.

[0036] It should be noted that the downstream attachment zone covers all areas of the clothing except for the arm area, below the buttocks, and in front of the knees. This includes the main downstream attachment areas such as the chest, abdomen, front waist, back, front thighs, and front calves, as well as the parts in close contact with the equipment. This downstream design significantly reduces frictional drag during high-speed gliding, stabilizes the clothing's shape, and provides compression and coverage to the athlete's soft tissues, thereby optimizing the overall aerodynamic profile.

[0037] Specifically, the easily separable region has a three-layer composite structure, including an outer fabric layer, an inner fabric layer, and a polymer film layer disposed between the two. The outer fabric layer and polymer film layer of the easily separable zone can be the same as those of the co-current attachment zone.

[0038] The difference is that the inner fabric layer of the easily separable zone has pits or longitudinal grooves, which can be formed by weaving or laser engraving.

[0039] Specifically, the pits have a diameter of 2mm to 3mm and a depth of 0.2mm to 0.4mm; the pits are arranged in a hexagonal honeycomb pattern, and the distance between adjacent pits is 1 to 1.5 times the diameter of the pit.

[0040] It should be noted that the easily separable zone is the area where flow transition or reattachment is likely to occur. By introducing turbulence textures, this structure enhances the stability of the local flow field without significantly increasing frictional drag, resulting in an earlier decrease in drag and no significant increase in frictional drag at high speeds.

[0041] Specifically, the dynamic deformation zone is a single-layer four-way stretch fabric structure. The four-way stretch fabric is a high-elastic fiber warp-knitted fabric with a longitudinal breaking elongation ≥150%, a transverse breaking elongation ≥180%, and a recovery rate ≥95%, possessing good resilience and local stretching ability.

[0042] It should be noted that the single-layer four-way stretch fabric structure refers to the simultaneous weaving of elastic warp and elastic weft yarns into the same woven fabric (or weft-knitted fabric), so that the fabric has continuous elasticity in both warp and weft directions (i.e., four sides).

[0043] Compared with existing technologies, this invention uses a four-way stretch knitted fabric in the area in front of the knee and below the hip, with a longitudinal breaking elongation of ≥150%, a transverse elongation of ≥180%, and a recovery rate of ≥95%. Under instantaneous tensile conditions of 3.5kN / m, the surface ripple height is <0.2mm, and the additional resistance fluctuation during the starting phase is <0.3N. It balances the degree of freedom required for large-amplitude flexion and extension movements with the close fit and wrinkle-free performance during high-speed gliding, solving the problem of traditional high-modulus fabrics easily wrinkling in dynamic areas and inducing instantaneous flow separation.

[0044] Specifically, adjacent easily separable zones, dynamically deformable zones, and downstream attachment zones are connected by seams, such as... Figures 1-2 As shown, The specific stitching settings are as follows: Side main structural line L1: Starting at the center point P1 of the lower axilla, it extends downwards along the lateral line to the hip and outer thigh, then from the knee towards the front of the body, and finally extends to the anteromedial side of the ankle.

[0045] L2, the center line of the inner thigh: Starting at the perineum point P2, it extends downwards along the inner thigh line, then from the knee towards the front of the body, eventually extending to the anterolateral aspect of the ankle.

[0046] Chest structure line L3: Starting at the center point P3 of the lower edge of the anterior neck, it extends downward along the anterior midline of the body to the chest and abdomen, until it reaches the perineum at point P2, where it closes and connects with the back structure line L4.

[0047] L4, the central structural line of the back: It begins at the center point P4 of the lower edge of the back of the neck, extends downward along the posterior midline of the body to the interscapular region and lumbar region, and connects with the chest structure line L3 at the perineum point P2.

[0048] L5, an internal structural line in the arm: Starting at the center point P1 of the lower axilla, the line descends along the inner side of the arm, extending from the medial side of the humerus to the elbow joint and the ulnar side of the forearm, and finally reaching the medial side of the wrist. The inner arm structure line L5 avoids the high-speed shear zone on the dorsolateral aspect of the arm, reducing the disturbance of the sleeve structure to the attached airflow and improving the stability and continuity of the local flow field.

[0049] First shoulder structure line L6: It begins at the lateral shoulder (extending 20-50mm outward from the lateral neck point P5), extending anteriorly and posteriorly to the center point of the lower armpit P1. L6 extends to the hand side, forming... Second shoulder structure line L7: It begins approximately 30–80 mm below the center point P3 of the lower edge of the anterior neck, extends horizontally from the sternoclavicular region to both shoulders, and connects to the first shoulder structure line L6.

[0050] It should be noted that the design of the first shoulder structure line L6 and the second shoulder structure line L7 avoids the high-pressure surface directly facing the front of the neck and clavicle area.

[0051] First leg structure line L8: Located above the knee, it connects the main structural line L1 on the side of the body with the center line L2 on the inner side of the leg, and is used to achieve multi-angle splicing of the garment template in the area above the knee joint.

[0052] The area formed between the first shoulder structure line L6, the second shoulder structure line L7, and the first leg structure line L8 is the anterior midline region of the chest and abdomen.

[0053] Second leg structure line L9: Located below the knee, connecting the side structural lines, it forms another spliced ​​ring band in the free movement zone of the knee joint. The anterior knee ring band area is formed between the first leg structural line L8 and the second leg structural line L9.

[0054] It should be noted that the first leg structure line L8 and the second leg structure line L9, combined with four-way stretch fabric, provide the knee joint with the high degree of elasticity required for flexion and extension movements.

[0055] The first hip structure line L10 starts from the lower outer part of the hip, extends diagonally backward to below the groin, and connects with the inner center line L2 of the leg.

[0056] The second hip structure line L11: It starts from the lower middle part of the outer hip area, extends diagonally backward to below the groin, and connects with the inner center line L2 of the leg. The lower hip area is formed between the first hip structure line L10 and the second hip structure line L11.

[0057] It should be noted that the first hip structure line L10 and the second hip structure line L11 follow the streamline of the hip surface, which minimizes the risk of local de-flow caused by abrupt curvature changes in this area, while providing sufficient splicing margin and flexibility during the starting action.

[0058] The first cap structure line L12 and the second cap structure line L13 are symmetrical about the top center line (top occipital point) and extend vertically downwards to the back of the neck area.

[0059] Horizontal structural line L14: Extending circumferentially from the base of the neck, passing through the center point P3 of the lower edge of the anterior neck and the center point P4 of the lower edge of the posterior neck.

[0060] L15, the structural line of the pedal section: It is installed around the instep to achieve a highly elastic splicing connection of the foot template.

[0061] During implementation, the stitching scheme further divides the easily separable area, dynamic deformation area, and flow-adhesive area into the shoulder-scapula outer edge area, waist-hip transition area, inner arm area, chest and abdomen front midline area, main back area, thigh-calf front area, knee ring area, and hip area. After each area is shaped and processed, it is further sewn together to obtain the finished competition uniform.

[0062] Preferably, a low-thickness edge-sealing technique is used to control the edge thickness to within 1.2–1.5 times the thickness of the adjacent fabric.

[0063] Preferably, a heat-bonded TPU windproof strip is added inside the vertical structural line in the center of the back to significantly reduce the interference of the stitching protrusion on the boundary layer.

[0064] Compared with existing technologies, this invention utilizes a streamlined structural line layout, arranging the main seam along the dominant airflow direction to avoid high-shear, easily detached areas such as the back of the legs and the outer back of the arms. It also employs a low-thickness edge-sealing technique, controlling the seam thickness to within 1.2–1.5 times the thickness of the adjacent fabric. A heat-bonded TPU windproof strip (10mm wide, 0.2mm thick) is added inside the vertical structural line in the center of the back, significantly reducing the interference of seam protrusions on the boundary layer. The velocity loss rate in the main back flow area is reduced by 0.8%, the surface roughness Ra is reduced from 12µm to 4µm, and the airflow permeability in the seam area is reduced to 0mL / (cm²·s), effectively suppressing local vortex streets and pressure fluctuations, achieving a "seamless" effect.

[0065] Preferably, a guide rib structure extending in parallel with the airflow direction is provided in the shoulder-scapular outer edge region.

[0066] Specifically, the guide rib structure is located in the area formed by extending outward from the side neck point P5 to the acromion point; and extending downward from the horizontal line of the side neck point P5 to the horizontal line of the lower axillary center point P1.

[0067] Preferably, such as Figure 4 As shown, the flow-guiding rib structure is defined to extend outward from the side neck point P5 to the acromion point at a distance of W1, and extend downward from the horizontal line of the side neck point P5 to the horizontal line of the lower armpit center point P1 at a distance of H1. The widths W1´ and H1´ of the flow-guiding rib structure setting area satisfy: W1´=0.7W1~0.9W1, H1´=0.5H1~0.7H1.

[0068] Specifically, the guide ribs are made of flexible silicone or thermoplastic polyurethane material and are embedded into the surface of the outer fabric layer by hot pressing-in-mold injection molding, hot pressing bonding or 3D printing.

[0069] Specifically, the guide ribs are linear strips with an arc or trapezoidal cross-section, a width of 0.8mm to 1.2mm, a height of 0.4mm to 0.6mm, and a spacing of 5mm to 7mm.

[0070] Specifically, the angle between the direction of the guide ribs and the direction of the airflow during gliding is no more than 15°.

[0071] It should be noted that the flow-guiding rib structure can effectively induce the backward convergence of the incoming flow at the upper edge of the shoulder, extend the local boundary layer adhesion path, and reduce the tendency of the surrounding fluid to form irregular transverse vortices at this location, thereby improving the continuity and stability of the flow field in the entire shoulder-back transition zone. The flow-guiding ribs are integrally molded with the fabric system, without any additional heavy structure, and have good dynamic adaptability and wearing comfort.

[0072] Preferably, the main area on the back is provided with a regularly arranged spoiler protrusion structure.

[0073] Specifically, such as Figure 4 As shown, the area where the turbulence protrusion structure is set satisfies: A vertical line extending outward from the lower corner of the scapula to the center point P1 of the lower armpit; a horizontal line extending upward from the lower corner of the scapula to the center point P1 of the lower armpit.

[0074] Preferably, W2 is defined as the vertical distance extending outward from the lower corner of the scapula to the center point P1 of the lower armpit, and H2 is defined as the horizontal distance extending upward from the lower corner of the scapula to the center point P1 of the lower armpit. The widths W2´ and H2´ of the area where the turbulence protrusion structure is set satisfy: W2´=0.7W2~0.9W2, H2´=0.7H2~0.9H2.

[0075] Specifically, the turbulence protrusions are hemispherical or low conical in shape, with a diameter of 3mm to 6mm, a height of 0.4mm to 0.6mm, and a spacing of 8mm to 15mm.

[0076] It should be noted that the turbulence protrusion structure can form a regular disturbance zone in the high curvature area while maintaining the fit and flexibility of the garment, thereby improving the boundary layer stability, enhancing the adhesion ability, significantly suppressing flow separation and mainstream disturbance in this area, and effectively maintaining the integrity of the back flow field during gliding.

[0077] Compared with existing technologies, this invention, by setting flexible silicone / TPE guide ribs (0.5mm high, 6mm spacing, angle ≤15° with the mainstream direction) on the shoulder, demonstrates through CFD simulation that this structure extends the reattachment length of the boundary layer in the shoulder-back transition zone by 18mm, reduces the airflow separation angle from 22° to 14°, decreases the lateral flow velocity in the high-pressure zone of the shoulder by 11%, and reduces the tail vortex intensity by 19%. Furthermore, by arranging a turbulence protrusion array (4mm diameter, 0.5mm high, 10mm center-to-center distance, densely arranged in triangular or hexagonal shapes) on the outer edge of the scapula, the flow separation line in the abrupt curvature change zone of the back is successfully shifted down by approximately 40mm, further reducing the Cd value by 0.010 at a wind speed of 35m / s.

[0078] Preferably, the flow guide ribs and the turbulence protrusions can be integrally formed by hot pressing-hot pressing-in-mold injection molding or 3D printing, with dimensional tolerances controlled within ±0.05mm.

[0079] During implementation, the 3D printing step size is selected to be below 20μm to control the dimensional tolerance within ±0.05mm.

[0080] Compared with existing technologies, this invention integrates the flow-guiding ribs and turbulence-disrupting protrusions through hot pressing-hot pressing-in-mold injection molding or 3D printing, with dimensional tolerances controlled within ±0.05mm. Wind tunnel testing of 200 sets of finished garments in the same batch showed that the standard deviation of the drag coefficient Cd σ≤0.003, meeting the consistency requirements of national-level equipment, fully verifying the reproducibility and stability of the technical solution in this application on an industrial scale.

[0081] To further illustrate the technical solution of the present invention, the following embodiments and comparative examples are provided: Example 1 This embodiment discloses a drag-reducing racing suit for bobsleigh. The suit adopts a one-piece, one-piece structure, covering the entire torso area of ​​the athlete from the head to the ankles, and includes multiple areas such as the shoulders, back, waist and hips, arms, knees and legs.

[0082] Based on the airflow distribution and posture changes of athletes during prone gliding, and combined with fluid numerical simulation and wind tunnel test results, the overall clothing structure and fabric configuration were systematically optimized. The aim was to improve aerodynamic performance while also ensuring comfort and athletic functionality. The results are as follows: Easily separable regions: located at the outer edge of the shoulder and scapula, the transition between the waist and hip, and the inner side of the arm. In CFD simulations, the wall shear stress τ in these regions... w <1.2 Pa and pressure gradient p > 0.05 Pa / mm; Downstream attachment zone: located along the anterior midline of the chest and abdomen, the main back region, and the anterior aspect of the thigh and calf. In CFD simulation, the wall shear stress τ in this region... w ≥1.2Pa, pressure gradient p≤0.05Pa / mm and surface curvature κ≤0.08mm -1 ; Dynamic deformation zone: located in the anterior knee ring and under the buttocks region, where the angular acceleration during movement is >1500° / s² and the rate of curvature change Δκ / Δt is >0.15mm. -1 .

[0083] The downstream attachment area includes the anterior midline region of the chest and abdomen, the main region of the back, and the anterior region of the thigh and calf. The anterior midline region of the chest and abdomen: from the lower border of the clavicle to the xiphoid process and the surface of the pubic symphysis; Main back region: from the spinous process of the 7th cervical vertebra to the lumbosacral junction and 5 mm above the gluteal cleft; Front thigh-lower leg region: a 20mm band within the line connecting the anterior superior iliac spine to the upper border of the patella and the lateral border of the tibialis anterior muscle.

[0084] The dynamic deformation zone includes the anterior knee ring area and the lower hip area; Anterior circumferential band region: a band extending from 60mm above the upper edge of the patella to 50mm below the lower edge of the patella; The area below the buttocks: the area from the ischial tuberosity to the transverse gluteal crease and the 25mm area inside the posterior thigh fold.

[0085] The downstream attachment zone has a three-layer composite structure, including an outer fabric layer, an inner fabric layer, and a polymer film layer disposed between the two; Both the outer and inner fabric layers of the downstream attachment zone are made of high-density elastic knitting with a surface density of 150 g / m², a thickness of 0.3 mm, and an elongation of ≥120%. The polymer film layer is an airtight polyurethane film, such as thermoplastic polyurethane (TPU) film material, with a thickness of 20μm, a tensile strength of not less than 30MPa, and an elongation at break of more than 400%.

[0086] The easily separable region has a three-layer composite structure, including an outer fabric layer, an inner fabric layer, and a polymer film layer disposed between the two; The outer fabric layer and polymer film layer of the easily separable zone can be the same as those of the co-current attachment zone.

[0087] The inner fabric layer of the easily separable zone is a pit or longitudinal groove, which can be formed by weaving or laser engraving.

[0088] The pits are 2mm in diameter and 0.2mm in depth; the pits are arranged in a hexagonal honeycomb pattern, and the distance between adjacent pits is 1 times the diameter of the pit.

[0089] The dynamic deformation zone is a single-layer four-way stretch fabric structure. The four-way stretch fabric is a high-elastic fiber warp-knitted fabric with a longitudinal breaking elongation ≥150%, a transverse breaking elongation ≥180%, and a recovery rate ≥95%, possessing good resilience and local stretching ability.

[0090] Adjacent easily separable zones, dynamic deformation zones, and downstream attachment zones are connected by sutures, such as... Figures 1-2 As shown, The specific stitching settings are as follows: Side main structural line L1: Starting at the center point P1 of the lower axilla, it extends downwards along the lateral line to the hip and outer thigh, then from the knee towards the front of the body, and finally extends to the anteromedial side of the ankle.

[0091] L2, the center line of the inner thigh: Starting at the perineum point P2, it extends downwards along the inner thigh line, then from the knee towards the front of the body, eventually extending to the anterolateral aspect of the ankle.

[0092] Chest structure line L3: Starting at the center point P3 of the lower edge of the anterior neck, it extends downward along the anterior midline of the body to the chest and abdomen, until it reaches the perineum at point P2, where it closes and connects with the back structure line L4.

[0093] L4, the central structural line of the back: It begins at the center point P4 of the lower edge of the back of the neck, extends downward along the posterior midline of the body to the interscapular region and lumbar region, and connects with the chest structure line L3 at the perineum point P2.

[0094] L5, an internal structural line in the arm: Starting at the center point P1 of the lower axilla, the line descends along the inner side of the arm, extending from the medial side of the humerus to the elbow joint and the ulnar side of the forearm, and finally reaching the medial side of the wrist. The inner arm structure line L5 avoids the high-speed shear zone on the dorsolateral aspect of the arm, reducing the disturbance of the sleeve structure to the attached airflow and improving the stability and continuity of the local flow field.

[0095] First shoulder structure line L6: It begins at the lateral shoulder (extending 20-50mm outward from the lateral neck point P5), extending anteriorly and posteriorly to the center point of the lower armpit P1. L6 extends to the hand side, forming... Second shoulder structure line L7: It begins approximately 30–80 mm below the center point P3 of the lower edge of the anterior neck, extends horizontally from the sternoclavicular region to both shoulders, and connects to the first shoulder structure line L6.

[0096] First leg structure line L8: Located above the knee, it connects the main structural line L1 on the side of the body with the center line L2 on the inner side of the leg, and is used to achieve multi-angle splicing of the garment template in the area above the knee joint.

[0097] The area formed between the first shoulder structure line L6, the second shoulder structure line L7, and the first leg structure line L8 is the anterior midline region of the chest and abdomen.

[0098] Second leg structure line L9: Located below the knee, connecting the side structural lines, it forms another spliced ​​ring band in the free movement zone of the knee joint. The anterior knee ring band area is formed between the first leg structural line L8 and the second leg structural line L9.

[0099] The first hip structure line L10 starts from the lower outer part of the hip, extends diagonally backward to below the groin, and connects with the inner center line L2 of the leg.

[0100] The second hip structure line L11: It starts from the lower middle part of the outer hip area, extends diagonally backward to below the groin, and connects with the inner center line L2 of the leg. The lower hip area is formed between the first hip structure line L10 and the second hip structure line L11.

[0101] The first cap structure line L12 and the second cap structure line L13 are symmetrical about the top center line (top occipital point) and extend vertically downwards to the back of the neck area.

[0102] Horizontal structural line L14: Extending circumferentially from the base of the neck, passing through the center point P3 of the lower edge of the anterior neck and the center point P4 of the lower edge of the posterior neck.

[0103] L15, the structural line of the pedal section: This embodiment focuses on structural continuity, surface smoothness, and control of high-speed airflow disturbance in the garment sewing process design to further reduce the risk of fluid interference on the outer surface of the garment and improve overall aerodynamic performance. The sewing structure and sealing treatment include the following: Low-thickness binding stitching is preferably used at the sewing points of each structural line of the garment. This sewing method achieves a smooth surface transition at the structural joints. A windproof sealing strip is adhered to the inside of the back structural line L4 of the garment. This windproof strip is a heat-pressed elastic polyurethane film tape, 10mm wide and 0.2mm thick, possessing good resilience and adhesion stability; it can completely cover the seams and achieve a smooth local surface transition, enhancing the adhesion continuity and flow field stability of the main back area.

[0104] A flow-guiding rib structure extending parallel to the airflow direction is set in the shoulder-scapular outer edge region, such as... Figure 3 As shown.

[0105] The widths W1´ and H1´ of the flow guide rib structure setting area satisfy: W1´=0.7W1, H1´=0.5H1.

[0106] The flow guide ribs are made of flexible silicone or thermoplastic polyurethane material and are embedded into the surface of the outer fabric layer through 3D printing.

[0107] The guide ribs are linear strips with an arc or trapezoidal cross-section, a width of 0.8 mm, a height of 0.4 mm, and a spacing of 5 mm.

[0108] The direction of the guide ribs is 10° with the direction of the airflow during gliding.

[0109] The main area on the back features a regularly arranged spoiler bump structure.

[0110] The widths W2´ and H2´ of the area where the turbulence protrusion structure is set satisfy: W2´=0.7W2, H2´=0.9H2.

[0111] The turbulence bumps are hemispherical or low conical in shape, with a diameter of 3mm, a height of 0.6mm, and a spacing of 8mm.

[0112] Comparative Example 1: The competition uniform described in this comparative example adopts a uniform overall structural design, with all parts constructed from the same double-layer composite fabric. This double-layer composite fabric comprises an outer smooth fabric, an inner smooth fabric, and a middle layer of non-breathable high-polymer polyurethane film. The knee and lower hip areas use a high-elastic four-way stretch fabric. This competition uniform does not have any flow-guiding textured fabric on the arms, no flow-guiding structure on the shoulders, and no flow-guiding protrusions in the scapular area; otherwise, it is the same as in Example 1.

[0113] Comparative Example 2: The competition uniform described in this comparative example is basically the same as that of the present invention in terms of overall fabric structure and zone layout, namely, it adopts a functional double-layer composite fabric, with a smooth fabric structure in the legs and torso, an inner layer of turbulent textured fabric in the arm area, and a high-elastic four-way stretch fabric in the knee and hip areas. The competition uniform described in this example does not have a guide rib structure arranged along the airflow direction in the shoulder area, nor does it have a turbulent protrusion structure in the scapula area for disturbing the boundary layer, otherwise it is the same as in Example 1.

[0114] To verify the superior aerodynamic performance of the steel-framed bobsleigh drag-reducing racing suit described in this invention, systematic wind tunnel tests were conducted on the suit designs of the embodiment and the comparative embodiment. The test procedures and analysis methods are as follows: The test uses an open-type low-speed wind tunnel system with a cross-sectional area of ​​1.2m×1.2m and a wind speed adjustment range of 11–35m / s. The test platform is equipped with a six-component force balance (with a measurement accuracy of 0.01N) to record the drag data experienced by the model in real time.

[0115] The test model was a standard 3D-printed human supine gliding posture model designed based on the body parameters of professional athletes from the International Bobsleigh and Luge Federation (IBSF). The model's outer surface was smooth, without any additional aerodynamic components, ensuring a consistent gliding posture and guaranteeing a single, reliable test variable. The embodiment and comparison clothing were worn on the model's surface to ensure a consistent fit and eliminate the influence of differences in wearing methods.

[0116] Each garment was tested three times at seven wind speeds: 11 m / s, 15 m / s, 19 m / s, 23 m / s, 27 m / s, 31 m / s, and 35 m / s. The average total drag value F was recorded. d Given wind speed V, dynamic pressure Q, and the drag coefficient Cd, calculate the drag coefficient Cd. The formula for calculating the drag coefficient Cd is as follows:

[0117] In the formula, F d ρ is the resistance, measured in N; ρ is the fluid density, measured in kg / m³; V is the fluid velocity relative to the object, measured in m / s; A is the reference area of ​​the object moving in the fluid, measured in m².

[0118] Test results show that the average drag coefficient of the embodiment described in this invention is lower than that of the comparative example under all test wind speed conditions, especially in the high wind speed range (V≥25m / s), where the difference is more significant. The highest drag reduction rate reaches 5%, and the increase in drag coefficient with increasing wind speed is significantly slowed down. This indicates that the present invention, through functionalized fabric partitioning, shoulder guide structure, and scapular disturbance design, effectively improves boundary layer adhesion stability and overall streamline consistency, significantly improving aerodynamic performance during high-speed gliding. Specific test data are shown in Table 1 and... Figure 5 : Table 1. Speed-drag coefficient test results for the examples and comparative examples.

[0119] The results show that in the high-speed taxiing range of 25m / s to 35m / s, the average drag coefficient Cd is reduced by 3.2% to 5.0% compared with the undivided scheme, and the slope of Cd with the increase of wind speed decreases by 42%, which directly achieves effective suppression of high-proportion pressure difference drag.

[0120] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A drag-reducing racing suit for steel-framed bobsleighs, characterized in that, The skeleton racing suit covers all areas of the body except the face and is divided into sections as follows: Easily separable zones: located at the outer edge of the shoulder-scapula, the transition between the waist and hip, and the inner side of the arm. In CFD simulation, the wall shear stress τ in these easily separable zones... w <1.2 Pa and pressure gradient p > 0.05 Pa / mm; The downstream attachment zone is located along the anterior midline of the chest and abdomen, the main back region, and the anterior aspect of the thigh and calf. In CFD simulation, the wall shear stress τ in this downstream attachment zone is... w ≥1.2Pa, pressure gradient p≤0.05Pa / mm and surface curvature κ≤0.08mm -1 ; Dynamic deformation zone: located in the anterior knee ring and under the buttocks region, where the angular acceleration during movement is >1500° / s² and the rate of curvature change Δκ / Δt is >0.15mm. -1 .

2. The drag-reducing racing suit for steel-framed bobsleighs according to claim 1, characterized in that, The easily separable areas include the shoulder-scapular border region, the waist-hip transition region, and the inner arm region; Shoulder - outer edge of scapula region: a band-shaped area 20mm lateral to the line connecting the lateral neck point to the acromion and the inferior angle of the scapula; The transition zone between the waist and hips: the area from the lower edge of the iliac crest to the upper bundle of the gluteus maximus and the 15mm inner side of the starting line of the posterolateral thigh. Inner arm region: the area 10 mm anterior to the line connecting the axillary point to the medial condyle of the humerus and the styloid process of the ulna.

3. The drag-reducing racing suit for steel-framed bobsleighs according to claim 2, characterized in that, A flow-guiding rib structure extending in the direction of airflow is set in the shoulder-scapular outer edge region.

4. The drag-reducing racing suit for steel-framed bobsleighs according to claim 1, characterized in that, The downstream attachment area includes the anterior midline region of the chest and abdomen, the main region of the back, and the anterior region of the thigh and calf. The anterior midline region of the chest and abdomen: from the lower border of the clavicle to the xiphoid process and the surface of the pubic symphysis; Main back region: from the spinous process of the 7th cervical vertebra to the lumbosacral junction and 5 mm above the gluteal cleft; Front thigh-lower leg region: a 20mm band within the line connecting the anterior superior iliac spine to the upper border of the patella and the lateral border of the tibialis anterior muscle.

5. The drag-reducing racing suit for steel-framed bobsleighs according to claim 4, characterized in that, The main area on the back features a regularly arranged spoiler bump structure.

6. The drag-reducing racing suit for steel-framed bobsleighs according to any one of claims 1-5, characterized in that, The co-current attachment zone and the easy separation zone are three-layer composite structures, including an outer fabric layer, an inner fabric layer, and a polymer film layer disposed between the two.

7. The drag-reducing racing suit for steel-framed bobsleighs according to claim 6, characterized in that, The outer and inner fabric layers of the downstream attachment zone and the outer fabric layer of the easily separable zone are all made of high-density elastic knitting with a surface density of 150g / m²~180g / m², a thickness of 0.3mm~0.5mm, and an elongation of ≥120%.

8. The drag-reducing racing suit for steel-framed bobsleighs according to claim 6, characterized in that, The inner fabric layer of the easily separable zone has pits or longitudinal grooves.

9. The drag-reducing racing suit for steel-framed bobsleighs according to claim 1, characterized in that, The dynamic deformation zone includes the anterior knee ring area and the lower hip area; Anterior circumferential band region: a band extending from 60mm above the upper edge of the patella to 50mm below the lower edge of the patella; The area below the buttocks: the area from the ischial tuberosity to the transverse gluteal crease and the 25mm area inside the posterior thigh fold.

10. The drag-reducing racing suit for steel-framed bobsleighs according to claim 9, characterized in that, The dynamic deformation zone is a single-layer four-way stretch fabric structure with longitudinal breaking elongation ≥150%, transverse breaking elongation ≥180%, and recovery rate ≥95%.

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