Motorcycle drag reduction and noise reduction optimization design method based on bionic technology

Abstract

The application discloses a motorcycle drag reduction and noise reduction optimization design method based on a bionic technology, and comprises the following steps: S1, simulating and analyzing a flow field and a sound field during motorcycle driving; S2, determining a position of a concave-convex structure based on the simulation analysis result of the flow field and the sound field of the motorcycle in S1; S3, designing and optimizing parameters of the concave-convex structure through an artificial intelligence optimization design platform; and S4, manufacturing the concave-convex structure according to the parameters of the concave-convex structure obtained in S3, installing the concave-convex structure to a target position of the motorcycle, and completing the design. The application can change the air flow mode to achieve the target of aerodynamic drag reduction and aerodynamic noise reduction through the bionic flow control method from the flow nature, and simultaneously avoids active control means to avoid increasing the system complexity, and realizes an integrated solution of aerodynamic drag reduction and aerodynamic noise reduction.

Description

Technical Field

[0001] This invention relates to the field of motorcycle design technology, and in particular to a method for optimizing motorcycle drag reduction and noise reduction based on biomimetic technology. Background Technology

[0002] Against the backdrop of global policies actively promoting energy conservation, emission reduction, and the green transformation of the transportation industry, improving the energy efficiency and optimizing the environmental performance of motorcycles, as a widely used personal transportation tool, has become an important direction for technological upgrading in the industry. Aerodynamic drag is a key factor affecting motorcycle energy consumption, especially at high speeds, where wind resistance energy consumption accounts for more than 60% of the total energy consumption of the vehicle. Increased drag directly leads to decreased fuel efficiency and increased emissions. Therefore, reducing motorcycle drag through aerodynamic design not only aligns with increasingly stringent fuel economy and exhaust emission regulations in various countries but also has clear practical significance for promoting the industry towards low-carbon and high-efficiency development. Under this trend, conducting research on motorcycle drag reduction technology and developing efficient, low-drag design schemes with independent intellectual property rights has become an inevitable technological path to respond to policy guidance, enhance product competitiveness, and promote sustainable development.

[0003] Wind noise is a key factor affecting rider hearing health and riding comfort during motorcycle riding. This noise is primarily generated by high-speed airflow passing over the rider's head, helmet surface, and the front structure of the motorcycle (such as the front fairing), and is a typical form of aerodynamic noise. Studies show that in a standard helmet without a noise reduction system, wind noise can exceed 100 decibels as speed increases. Prolonged exposure to noise levels above 85 decibels can lead to abnormal cochlear metabolic function and auditory nerve degeneration, causing irreversible noise-induced hearing loss. For professional riders, who often ride for more than 3 hours a day, the cumulative risk of noise exposure is even more pronounced. Currently, systematic research and practice on noise protection for motorcycle riders are insufficient, and effective technological innovation is urgently needed to achieve tangible improvements.

[0004] Currently, aerodynamic drag reduction technologies for motorcycles mainly focus on two directions: first, aerodynamic optimization of the overall vehicle configuration, which involves streamlining the overall shape and key components to reduce aerodynamic drag at the source; second, adding aerodynamic devices such as tail wings, spoilers, and deflectors to reduce drag through localized flow control. These technologies exhibit the following characteristics in practical applications: while overall vehicle configuration optimization can improve aerodynamic performance at the system level, it often involves overall styling changes, resulting in long development cycles and high costs; while adding aerodynamic devices is flexible and quick to implement, it increases structural complexity and vehicle weight, and some active control devices may introduce additional energy consumption, contradicting the initial goal of drag reduction and energy saving. Regarding the noise exposure problem for motorcycle riders, current noise reduction solutions mainly fall into two categories: vehicle structure noise reduction and rider equipment noise reduction. In terms of vehicle structure, noise reduction is achieved by integrating multiple layers of sound-absorbing and sound-insulating materials inside the fairing. In terms of rider equipment, noise reduction is mainly achieved by improving the internal structure of the helmet. There are currently two typical designs: one is to add a shock-absorbing and noise-reducing energy-absorbing device between the helmet shell and the EPS impact energy-absorbing layer, which absorbs wind noise vibration through the damping effect; the other is to design integrated earcups on both sides inside the helmet, combined with bone conduction headphone technology, which can effectively block external wind noise while transmitting key environmental sounds such as horns through bone conduction, thus taking into account both noise reduction effect and riding safety.

[0005] While existing drag reduction solutions have some effect, they still have significant limitations in terms of lightweighting and system integration. At the same time, traditional noise reduction technologies mostly focus on blocking noise propagation paths rather than controlling it from the root aerodynamic source—namely, flow separation and vortex structure evolution. Therefore, there is still room for improvement in noise reduction efficiency and overall effectiveness.

[0006] Therefore, how to provide a novel flow control method that can balance drag reduction and noise reduction, and is simple in structure and easy to integrate, has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] In view of this, the purpose of this invention is to provide a motorcycle drag reduction and noise reduction optimization design method based on biomimetic technology. It can start from the essence of flow and change the airflow mode through biomimetic flow control methods to achieve the goal of aerodynamic drag reduction and aerodynamic noise reduction, while avoiding active control means to avoid increasing system complexity, and realizing an integrated solution for aerodynamic drag reduction and aerodynamic noise reduction.

[0008] The present invention solves the technical problem by adopting the following technical solution:

[0009] A biomimetic design method for motorcycle drag reduction and noise reduction includes the following steps:

[0010] S1: Simulation analysis of the flow field and sound field during motorcycle movement;

[0011] S2: Based on the simulation analysis results of the motorcycle flow field and sound field in S1, determine the location where the concave and convex structures are applied;

[0012] S3: Optimize the parameters of the concave-convex structure through an artificial intelligence optimization design platform;

[0013] S4: Based on the parameters of the concave-convex structure obtained in S3, fabricate the concave-convex structure, install the concave-convex structure onto the target position on the motorcycle, and complete the design.

[0014] Furthermore, in S2, the method for determining the location of the applied concave-convex structure is as follows: perform flow field and sound field simulation analysis on a specific motorcycle model to obtain the flow structure that contributes significantly to the drag of the corresponding motorcycle model. Apply the concave-convex structure to the vehicle body position before the flow structure occurs for flow control. This position is the location where the concave-convex structure is applied.

[0015] Furthermore, the locations where the concave and convex structures are applied include both sides of the motorcycle's front fairing, the leading edge of the front wheel fender, and both sides of the motorcycle's footrests.

[0016] Furthermore, in S4, the method for designing and optimizing the parameters of the concave-convex structure using an artificial intelligence optimization design platform is as follows:

[0017] As an optimization problem, the optimization objectives should first be clearly defined. The primary objective is to minimize the drag coefficient of the motorcycle after applying the concave-convex structure. Secondly, the optimization objective is to reduce the total sound power level of the motorcycle after applying the concave-convex structure, using the amplitude, wavelength, and thickness of the concave-convex structure as design variables. Through 3D modeling and CFD technology, the aerodynamic drag and noise intensity of the motorcycle after applying different concave-convex structures are evaluated and calculated. Artificial intelligence optimization algorithms are then used to search for the optimal parameters within the design space of the concave-convex structure parameters. This process is iterated to ultimately optimize the concave-convex structure parameters that minimize the drag coefficient of the motorcycle while also reducing the total sound power level.

[0018] Furthermore, S5 is used to perform sound field calculations on the completed design and verify the noise reduction effect of adding the concave-convex structure, as follows:

[0019] The formula for acoustic energy in isotropic turbulence is derived using Lighthill acoustic analogy theory:

[0020]

[0021] Where AP is the total sound power per unit volume (W / m²) 3 ), A constant related to the longitudinal velocity. The root mean square of one of the velocity components. The longitudinal integral length scale is the velocity. For far-field density, For far-field sound speed;

[0022] The total sound power per unit volume is:

[0023]

[0024] in, The sound power level per unit volume. This is the reference sound power.

[0025] The present invention discloses a motorcycle drag reduction and noise reduction optimization design method based on biomimetic technology, which has the following beneficial effects:

[0026] This invention overcomes the shortcomings of existing technologies and achieves multiple advantages by applying concave-convex structures to key motorcycle components and optimizing structural parameters using flow field analysis methods. Firstly, it breaks through the bottleneck of existing technologies where drag reduction and noise reduction are separated. Based on flow field analysis, precise optimization of the concave-convex structure parameters simultaneously achieves optimal drag reduction and noise reduction, solving the problem of existing solutions being functionally limited and unable to synergistically enhance performance. Secondly, it is designed based on the core mechanism of the motorcycle's flow field, fundamentally improving the problems of airflow separation and vortex evolution. Compared to existing drag reduction solutions that rely on fine-tuning of local components, this method is more effective and has greater versatility. Thirdly, the application of the concave-convex structure is simple and easy, requiring no additional processing or modification of the motorcycle itself. This avoids the shortcomings of existing technologies, such as complex structures, high modification costs, and poor adaptability, and better meets the practical needs of motorcycles in terms of compact space and cost sensitivity. Attached Figure Description

[0027] Figure 1 This is a diagram of the instantaneous flow around the vehicle.

[0028] Figure 2 This is a schematic diagram showing the location of the concave and convex structures applied to the motorcycle.

[0029] Figure 3 This is a diagram of the front fairing with concave and convex structures applied to both sides;

[0030] Figure 4 This is a diagram of a mudguard with an uneven surface at its leading edge;

[0031] Figure 5 This is a diagram of a helmet with an uneven surface on the top;

[0032] Figure 6 It is a method flowchart. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Current aerodynamic drag reduction technologies for motorcycles mainly fall into two categories: drag reduction by the vehicle itself and drag reduction by additional devices. While various drag reduction methods exist, their effectiveness is limited. Current motorcycle wind noise control technologies primarily focus on blocking noise propagation paths. Drag reduction solutions are often limited to aerodynamic shape adjustments while neglecting acoustic benefits, and noise reduction solutions lack source control methods that address the flow mechanism. For motorcycles, platforms highly sensitive to space, cost, and overall performance, there is an urgent need for an integrated solution that addresses the fundamental nature of flow, using biomimetic flow control methods to alter airflow patterns to achieve aerodynamic drag reduction and noise reduction, while avoiding active control methods to prevent increased system complexity. Based on this, this invention proposes a technical solution that applies a biomimetic concave-convex leading edge structure system to motorcycle exterior design, aiming to achieve drag and noise reduction goals for motorcycles at high speeds.

[0035] The core of this invention is to analyze the turbulence during motorcycle operation using flow field analysis methods. Based on the results of the flow field analysis, it is found that three large vortex flows in the motorcycle flow field contribute significantly to aerodynamic drag, such as... Figure 1 As shown, there are vortices formed between the rider and the fairing due to airflow separation on both sides; a pair of opposing directional vortices formed on both sides of the underside of the motorcycle behind the front wheel; and a backflow vortex formed by the upward-washing airflow on both sides of the motorcycle below the rider's back. To address these vortex flows, concave and convex structures are applied to the sides of the motorcycle's front fairing, the leading edge of the front fender, and the sides of the helmet and footrests to control flow, delay airflow separation, reduce vortex intensity, and thus reduce wind resistance. Figures 2 to 5 As shown, where Figure 2 Position a is on both sides of the fairing, and position b is at the leading edge of the mudguard.

[0036] refer to Figure 6 The present invention discloses a motorcycle drag reduction and noise reduction optimization design method based on biomimetic technology, comprising the following steps:

[0037] S1: Simulation analysis of the flow field and sound field during motorcycle movement;

[0038] S2: Based on the simulation analysis results of the motorcycle flow field and sound field in S1, determine the location where the concave and convex structures are applied;

[0039] The method for determining the location of applying the concave-convex structure is as follows: perform flow field and sound field simulation analysis on a specific motorcycle model to obtain the flow structure that contributes the most to the drag of the corresponding motorcycle model. Apply the concave-convex structure to the position of the vehicle body before the flow structure occurs to control the flow. This position is the location where the concave-convex structure is applied.

[0040] The locations where the concave and convex structures are applied include both sides of the motorcycle's front fairing, the leading edge of the front wheel fender, and both sides of the motorcycle's footrests.

[0041] S3: Optimize the parameters of the concave-convex structure through an artificial intelligence optimization design platform;

[0042] The method for designing and optimizing the parameters of concave-convex structures using an artificial intelligence optimization design platform is as follows:

[0043] As an optimization problem, the optimization objectives should first be clearly defined. The primary objective is to minimize the drag coefficient of the motorcycle after applying the concave-convex structure. Secondly, the optimization objective is to reduce the total sound power level of the motorcycle after applying the concave-convex structure, using the amplitude, wavelength, and thickness of the concave-convex structure as design variables. Through 3D modeling and CFD technology, the aerodynamic drag and noise intensity of the motorcycle after applying different concave-convex structures are evaluated and calculated. Artificial intelligence optimization algorithms are then used to search for the optimal parameters within the design space of the concave-convex structure parameters. This process is iterated to ultimately optimize the concave-convex structure parameters that minimize the drag coefficient of the motorcycle while also reducing the total sound power level.

[0044] The parameters of the concave-convex structure have a certain proportional relationship with the characteristic length at the application location. Taking the front diffuser of a motorcycle as an example, the half-width of the diffuser is used as the reference length to design and optimize the parameters of the concave-convex structure. The parameter range of the concave-convex structure in other fields is summarized as the design space, with the amplitude range of 2.5%-12% of the chord length, the wavelength range of 10%-50% of the chord length, and the thickness of 20%-28% of the chord length.

[0045] S4: Based on the parameters of the concave-convex structure obtained in S3, fabricate the concave-convex structure, install the concave-convex structure onto the target position on the motorcycle, and complete the design.

[0046] S5: Perform sound field calculations on the completed design to verify the noise reduction effect of adding the concave-convex structure. The method is as follows:

[0047] The formula for acoustic energy in isotropic turbulence is derived using Lighthill acoustic analogy theory:

[0048]

[0049] Where AP is the total sound power per unit volume (W / m²) 3 ), A constant related to the longitudinal velocity. The root mean square of one of the velocity components. The longitudinal integral length scale is the velocity. For far-field density, For far-field sound speed;

[0050] The total sound power per unit volume is:

[0051]

[0052] in, The sound power level per unit volume. This is the reference sound power.

[0053] Flow field analysis was conducted on a general-purpose motorcycle, and the optimal amplitude and wavelength parameters of the concave-convex structure were obtained through optimization design. CFD simulation was used to verify that adding the concave-convex structure to the front air intake of the motorcycle achieved the effect of reducing the drag coefficient by 5.6% and the sound power level of the motorcycle by 24%.

[0054] This invention overcomes the shortcomings of existing technologies and achieves multiple advantages by applying concave-convex structures to key motorcycle components and optimizing structural parameters using flow field analysis methods. Firstly, it breaks through the bottleneck of existing technologies where drag reduction and noise reduction are separated. Based on flow field analysis, precise optimization of the concave-convex structure parameters simultaneously achieves optimal drag reduction and noise reduction effects, solving the problem of existing solutions having limited functionality and failing to synergistically enhance performance. Secondly, it is designed based on the core mechanism of the motorcycle's flow field, fundamentally improving the problems of airflow separation and vortex evolution. Compared to existing drag reduction solutions that rely on fine-tuning of local components, this invention offers superior performance and greater versatility. Thirdly, the application of the concave-convex structure is simple and easy, requiring no additional processing or modification of the motorcycle itself. This avoids the shortcomings of existing technologies, such as complex structures, high modification costs, and poor adaptability, and better meets the practical needs of motorcycles in terms of compact space and cost sensitivity.

[0055] Numerical simulation studies show that the aerodynamic field of a motorcycle and its rider is mainly composed of multiple flow structures with distinct characteristics. Analysis indicates that flow separation in the front fairing region and the resulting backflow vortices are the primary sources of aerodynamic drag. Based on the characteristics of this separated flow, a specific concave-convex surface structure was designed on both sides of the front fairing. Experimental results demonstrate that this structure achieves a comprehensive optimization effect, reducing aerodynamic drag by 5.6% and aerodynamic noise intensity by 24%. This result fully verifies the effectiveness and application potential of the concave-convex structure in motorcycle drag reduction and noise reduction, laying a solid foundation for subsequent technology research and development and industrialization. Based on this, this invention further optimizes the parameter design and installation layout of the concave-convex leading edge structure, systematically adapting and improving key aerodynamic components of the motorcycle. The aim is to overcome existing technological bottlenecks and achieve a synergistic improvement in drag reduction, noise reduction, and power performance, providing a new technical solution for the motorcycle industry to meet energy conservation and emission reduction policy requirements and enhance product core competitiveness.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A motorcycle drag reduction and noise reduction optimization design method based on biomimetic technology, characterized in that, Includes the following steps: S1: Simulation analysis of the flow field and sound field during motorcycle movement; S2: Based on the simulation analysis results of the motorcycle flow field and sound field in S1, determine the location where the concave and convex structures are applied; S3: Optimize the parameters of the concave-convex structure through an artificial intelligence optimization design platform; S4: Based on the parameters of the concave-convex structure obtained in S3, fabricate the concave-convex structure, install the concave-convex structure onto the target position on the motorcycle, and complete the design.

2. The motorcycle drag reduction and noise reduction optimization design method based on biomimetic technology according to claim 1, characterized in that, In S2, the method for determining the location of the concave-convex structure is as follows: perform flow field and sound field simulation analysis on a specific motorcycle model to obtain the flow structure that contributes the most to the drag of the corresponding motorcycle model. Apply the concave-convex structure to the position of the vehicle body before the flow structure occurs to control the flow. This position is the location where the concave-convex structure is applied.

3. The motorcycle drag reduction and noise reduction optimization design method based on biomimetic technology according to claim 2, characterized in that, The locations where the concave and convex structures are applied include both sides of the motorcycle's front fairing, the leading edge of the front wheel fender, and both sides of the motorcycle's footrests.

4. The motorcycle drag reduction and noise reduction optimization design method based on biomimetic technology according to claim 3, characterized in that, In S4, the method for designing and optimizing the parameters of the concave-convex structure through the artificial intelligence optimization design platform is as follows: First, the optimization objective should be clearly defined. The most important objective is to minimize the drag coefficient of the motorcycle after applying the concave-convex structure. The second objective is to reduce the total sound power level of the motorcycle after applying the concave-convex structure. The amplitude, wavelength, and thickness of the concave-convex structure are used as design variables. The aerodynamic drag and noise intensity of the motorcycle after applying different concave-convex structures are evaluated and calculated through 3D modeling and CFD technology. The optimization algorithm of artificial intelligence is used to search for the best within the design space of the concave-convex structure parameters. The above process is iterated to finally optimize the concave-convex structure parameters that minimize the drag coefficient of the motorcycle and also reduce the total sound power level.

5. The motorcycle drag reduction and noise reduction optimization design method based on biomimetic technology according to claim 4, characterized in that, It also includes S5, which performs sound field calculations on the completed design to verify the noise reduction effect of adding the concave-convex structure. The method is as follows: The formula for acoustic energy in isotropic turbulence is derived using Lighthill acoustic analogy theory: ; Where AP is the total sound power per unit volume. A constant related to the longitudinal velocity. The root mean square of one of the velocity components. The longitudinal integral length scale is the velocity. For far-field density, For far-field sound speed; The total sound power per unit volume is: in, The sound power level per unit volume. This is the reference sound power.

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