Cab wind resistance contour optimization method based on digital twinning

Abstract

The invention relates to the technical field of digital twinning, and particularly discloses a cab wind resistance contour optimization method based on digital twinning, which comprises the following steps: S1, establishing a three-dimensional model of a cab, and calculating front wind resistance according to an included angle between planes; s2, marking a standard plane in the initial model, obtaining the air velocity of the standard plane, calculating the air pressure of the standard plane, and calculating the rising force based on the air pressure; s3, marking an influence surface in the initial model, obtaining the air velocity of the influence surface, calculating the air pressure of the influence surface, and calculating the downforce based on the air pressure; and S4, calculating the friction force and the wind resistance coefficient of the initial model, and selecting an optimal model based on the wind resistance coefficient. According to the method, the effect of the optimized cab wind resistance contour is judged through a more reasonable method, so that the cab wind resistance contour with the best effect is selected, the air resistance during vehicle running is reduced, the load and fuel consumption of an engine are reduced, and the running cost is saved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of digital twinning, in particular to a cab wind resistance profile optimization method based on digital twinning. BACKGROUND

[0002] The cab wind resistance profile refers to the overall shape and structural features of the cab of a vehicle when it moves in the air. When the vehicle is driving, the cab, as the main component of the front end of the vehicle, its shape and size have a significant impact on air flow. Simply put, the "attitude" of the cab in the air determines how the air flows through the vehicle, thereby affecting the size of the air resistance experienced by the vehicle.

[0003] Among them, the overall shape of the cab is the primary factor in determining the wind resistance profile. A streamlined design can better guide the air to flow smoothly around the cab, reducing the generation of air separation and vortex, thereby reducing wind resistance. On the contrary, a square and angular shape will cause the air to form a larger separation zone at the corner, increasing the wind resistance. And larger cab size usually increases wind resistance. Because a larger surface area means more areas in contact with the air, resulting in greater friction and pressure difference resistance. At the same time, a tall cab can also change the flow pattern of the air flow, making it more complex and unstable.

[0004] In the prior art, the commonly used cab wind resistance evaluation index is mainly the wind resistance coefficient, but the wind resistance coefficient can only reflect the air resistance of the vehicle under certain conditions, and cannot fully represent the performance of the cab in actual driving. And relying solely on the wind resistance coefficient cannot accurately evaluate these situations. Therefore, a more reasonable method is needed to judge the real effect of the optimized cab wind resistance profile, so as to select the best cab wind resistance profile, reduce the air resistance of the vehicle when driving, reduce the load of the engine, reduce fuel consumption, and save driving costs. SUMMARY

[0005] The purpose of the present application is to provide a cab wind resistance profile optimization method based on digital twinning, which solves the above technical problems.

[0006] The purpose of the present application can be achieved by the following technical solutions: A cab wind resistance profile optimization method based on digital twinning, comprising the following steps: S1: Establish a three-dimensional model of the cab and denote it as an initial model, let the initial model move forward at a preset speed v, denote the planes in the initial model as initial planes, obtain the angle θ between the initial planes and the horizontal plane, and calculate the frontal wind resistance of the initial model , wherein I represents the number of initial planes, S i represents the area of the i-th initial plane in the initial model, Pi θ represents the wind pressure at the i-th initial plane in the initial model. i This represents the angle between the i-th initial plane in the initial model and the horizontal plane. S2: Denote the plane where the chassis is located in the initial model as the standard plane, obtain the air velocity Q on the standard plane, and calculate the air pressure on the standard plane. Where W represents the preset static pressure constant, ρ represents the air density, and H represents the air density. Q The distance between the standard plane and the horizontal plane is represented by 'g', which represents the acceleration due to gravity. The lift force F is calculated. up =P Q S Q S Q The area representing a standard plane; S3: Denote the plane located above the standard plane as the influence surface, obtain the air velocity K of the influence surface, and calculate the air pressure of the influence surface. , where H Q_min H represents the minimum distance between the area of ​​influence and the horizontal plane. Q_max The maximum distance between the influence surface and the horizontal plane is used to calculate the downforce. J represents the number of affected areas, P K_j S represents the air pressure on the j-th affected surface. K_j θ represents the area of ​​the j-th influence surface. K_j This represents the angle between the j-th influence surface and the horizontal plane; S4: Calculate friction force μ represents the coefficient of friction between the tire and the ground, and G represents the weight of the cab. Calculate the drag coefficient of the initial model. S represents the area of ​​the front projection of the driver's cab; The 3D models are sorted in ascending order of drag coefficient FX, and the first 3D model in the sort is recorded as the optimal model and used as the optimization scheme for the cab drag profile.

[0007] As a further aspect of the present invention: in step S1, when calculating the frontal wind resistance FZ of the initial model, the frictional force between the air and the initial model is ignored.

[0008] As a further aspect of the present invention: in step S1, planes that are parallel to each other and have equal areas in the initial model are denoted as equilateral planes, and these equilateral planes are discarded and not included in the subsequent calculation of the drag coefficient.

[0009] As a further aspect of the present invention: in step S2, the standard plane is adjusted to be parallel to the horizontal plane, and the adjusted distance is the minimum distance between the standard plane and the horizontal plane.

[0010] As a further scheme of the present application: in the step S2, an air pressure interval [P sta , P sta +ε] is preset, if the calculated air pressure is out of the air pressure interval, it is recorded as abnormal air pressure, and the abnormal air pressure does not participate in the calculation of the lift and the down pressure, wherein P sta represents the standard atmospheric pressure, and ε represents the preset pressure threshold, and ε>0.

[0011] As a further scheme of the present application: in the step S3, an influence surface perpendicular to the horizontal plane is recorded as a non-influence surface, and the non-influence surface does not participate in the calculation of the down pressure.

[0012] As a further scheme of the present application: the protruding and recessed regions in the initial model are marked, and the maximum height G of the protruding region and the maximum depth D of the recessed region are obtained, if less than a preset influence threshold YX, it is recorded as a non-influence region, and the non-influence region does not participate in the subsequent calculation of the wind resistance coefficient.

[0013] As a further scheme of the present application: in the step S4, if there are three-dimensional models with equal wind resistance coefficients, the three-dimensional model with smaller cab front projection area is located in the front position in the sequence.

[0014] The cab is converted into a three-dimensional model, so that subsequent operations are facilitated, the front wind resistance generated when the three-dimensional model travels at a preset speed is calculated, the front wind resistance represents the resistance size of the three-dimensional model traveling at a preset speed, then the wind speed above the three-dimensional model and at the chassis is obtained, according to Bernoulli's principle, when the distance of the starting point is consistent, the path above the three-dimensional model is greater than the path of the chassis, so the air flow rate above the three-dimensional model is greater than the air flow rate of the chassis, and the greater the air flow rate, the smaller the air pressure it generates, because the air flow rates above the three-dimensional model and at the chassis are different, so there is a pressure difference, the pressure difference between the two is calculated according to the area, so that the influence of the vehicle's contour profile on its resistance can be judged, finally the friction is calculated through the gravity of the cab itself and the calculated lift and down pressure, so that the most suitable contour profile can be selected, in summary, the cab is converted into a three-dimensional model, the front wind resistance is calculated, the wind speed difference and the pressure difference between the top and the chassis are analyzed, the friction is calculated in combination with the gravity, the lift and the down pressure, the influence of the contour profile on the wind resistance is comprehensively evaluated, and the optimal design scheme is screened out to reduce the wind resistance, the engine power consumption and the energy consumption. BRIEF DESCRIPTION OF DRAWINGS

[0015] The present application will be further described below in conjunction with the drawings.

[0016] Figure 1It is a flowchart of a cab wind resistance profile optimization method based on digital twinning. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the protection scope of the present application.

[0018] Please refer to Figure 1 The present application is a cab wind resistance profile optimization method based on digital twinning, which comprises the following steps: S1: a three-dimensional model of the cab is established and recorded as an initial model, the initial model is made to move forward at a preset speed v, a plane in the initial model is recorded as an initial plane, an angle θ between the initial plane and the horizontal plane is obtained, and the frontal wind resistance of the initial model is calculated , wherein I represents the number of the initial planes, S i represents the area of the i th initial plane in the initial model, P i represents the wind pressure of the i th initial plane in the initial model, θ i represents the angle between the i th initial plane and the horizontal plane; S2: the plane where the chassis is located in the initial model is recorded as a standard plane, the air flow rate Q of the standard plane is obtained, and the air pressure of the standard plane is calculated , wherein W represents a preset static pressure constant, ρ represents the air density, H Q represents the distance between the standard plane and the horizontal plane, g represents the gravitational acceleration, and the lifting force F up is calculated Q , S Q , S Q represents the area of the standard plane; S3: a plane located above the standard plane is recorded as an influence plane, the air flow rate K of the influence plane is obtained, and the air pressure of the influence plane is calculated , wherein H Q_min represents the minimum distance between the influence plane and the horizontal plane, H Q_max represents the maximum distance between the influence plane and the horizontal plane, and the down pressure F is calculated, J represents the number of the influence planes, P K_j represents the air pressure of the j th influence plane, S K_j represents the area of the j th influence plane, θ K_j represents the angle between the j th influence plane and the horizontal plane; S4: the friction force is calculated , μ represents the friction factor between the tire and the ground, G represents the gravity of the cab, and the wind resistance coefficient of the initial model is calculated , S represents the area of the cab's front projection. The three-dimensional models are sorted in order of the wind resistance coefficient FX from small to large, and the first three-dimensional model in the sorted order is recorded as the optimal model and used as the cab wind resistance profile optimization scheme.

[0019] It should be noted that in the field of modern transportation, the energy consumption of vehicles is of great concern, and the wind resistance characteristics of the cab have a crucial influence on the overall energy consumption of the vehicle. In order to further study the wind resistance of the cab in order to optimize its shape design and reduce energy consumption, a comprehensive screening scheme based on three-dimensional model analysis is proposed.

[0020] Firstly, the cab is converted into a three-dimensional model, which is the basis of the entire research process. Through advanced three-dimensional modeling technology, the details of the cab are accurately restored, including the body lines, window shape, door structure, etc. This three-dimensional model not only has a high degree of authenticity, but also can provide accurate data support for subsequent calculations and analyses. In practical applications, professional three-dimensional modeling software can be used in combination with the actual size and design parameters of the cab to gradually build a complete three-dimensional model. In this way, subsequent operations can be based on this model, ensuring the accuracy and reliability of the analysis results, and the initial plane refers to any plane in the initial model, and the front wind resistance is calculated according to the angle between the initial plane and the horizontal plane.

[0021] After obtaining the three-dimensional model of the cab, the front wind resistance generated by the model when driving at a preset speed needs to be calculated. The preset speed here is set according to the typical working conditions of actual vehicle driving, such as the commonly used driving speed on the highway, etc. The front wind resistance represents the air resistance experienced by the three-dimensional model during driving, and it is one of the key factors affecting the energy consumption of the vehicle. In order to accurately calculate the front wind resistance, factors such as air density, flow rate, and the windward area of the cab need to be considered. By using the relevant principles and formulas of fluid mechanics and combining computer simulation technology, the front wind resistance value of the three-dimensional model under different driving conditions can be accurately calculated.

[0022] Next, the wind speed at the top of the three-dimensional model and at the chassis needs to be obtained. This step is crucial for analyzing the wind resistance characteristics of the cab. According to Bernoulli's principle, there is a close relationship between flow rate and pressure during fluid flow. When the starting point distance is consistent, due to the contour characteristics of the cab body, the air flow path at the top of the three-dimensional model is usually larger than that at the chassis. This is because the shape of the cab body causes the air at the top to flow around the body surface, while the air flow at the chassis is relatively smooth. This difference in path causes the air flow rate at the top to be greater than that at the chassis.

[0023] After understanding the difference in air flow rate, the change in pressure can be further analyzed according to Bernoulli's principle. According to the principle, the greater the air flow rate, the smaller the air pressure it produces. Therefore, during the driving process of the cab, due to the different air flow rates at the top and the chassis, a pressure difference will be formed between them. In order to accurately calculate this pressure difference, the areas at the top and the chassis need to be determined according to the specific shape and size of the cab. Then, combined with the previously calculated air flow rate and pressure relationship, the corresponding calculation formula can be used to obtain the pressure difference between the two.

[0024] This pressure difference value can directly reflect the influence of the vehicle contour on wind resistance. Different contour designs will result in different differences in air flow rate at the top and the chassis, and thus different pressure differences and pressure difference values. By calculating and analyzing various cab designs with different contours, the differences in wind resistance characteristics between them can be compared, and the contour design with the smallest wind resistance can be found.

[0025] However, in actual application, there is a key detail that needs special attention, which is the complex influence of the change in the angle between the top plane of the cab and the horizontal plane. When the angle between the top plane of the cab and the horizontal plane gradually increases, according to Bernoulli's principle, it can be clearly judged that the path of air flow at the top will become longer. This is because as the angle increases, the air at the top of the cab needs to flow along a more inclined surface, and the extension of its flow trajectory increases the path length.

[0026] Due to the increase in path length, according to the relationship between flow rate and pressure in Bernoulli's principle, under the condition that air flow and other conditions are relatively stable, the flow rate at the top will be affected. Specifically, the increase in path length will cause the air to cover a longer distance in the same time, resulting in an increase in flow rate. According to Bernoulli's principle, an increase in flow rate will result in a decrease in pressure. In this case, the pressure difference between the top of the cab and the chassis will change significantly, and the difference between the lift and the downward pressure will further increase.

[0027] From the perspective of mechanical effect, this change in pressure difference is equivalent to the air below generating an upward force, as if there is an invisible force lifting the cab upward. This phenomenon has a direct impact on the friction force, because the size of the friction force is closely related to the normal pressure between the contact surfaces. When the cab is subjected to an upward force, its normal pressure on the ground will decrease, thereby causing the friction force to decrease. However, there is a problem that needs to be analyzed in depth. In actual testing, in order to accurately study and compare the performance indicators of the cab under different conditions, the vehicle speed usually needs to remain constant. In this case, when the included angle increases, according to the formula for calculating the frontal wind resistance, it can be seen that sinθ (θ is the included angle between the plane above the cab and the horizontal plane) involved will increase accordingly. Since the frontal wind resistance is directly proportional to sinθ, the frontal wind resistance will also increase accordingly. This indicates that the frontal wind resistance does not simply show a single upward or downward trend, but is influenced by a combination of factors. With the change of the included angle between the plane above the cab and the horizontal plane, the change of the frontal wind resistance is more complex, which is related to and restricted by the change of the included angle, as well as the changes in air flow path, pressure difference and a series of changes.

[0028] Moreover, in actual situations, the outer shell area of the cab is not a fixed quantity. When the included angle changes, the outer shape of the cab will change, and its outer shell area will also change accordingly. For example, when the included angle increases, some parts of the cab may protrude more, causing the windward area to increase; while some parts may be relatively retracted, causing the windward area to decrease. This change in outer shell area will further affect the size of the frontal wind resistance, because the frontal wind resistance is also directly related to the windward area.

[0029] Therefore, when selecting the outer shape of the cab, we cannot only consider the change of a single factor, but need to consider the influence of the change of the included angle on the lifting force, the downward pressure, the friction force and the frontal wind resistance, and also take into account the change of the outer shell area of the cab. Only in this way can we comprehensively and accurately evaluate the pros and cons of different outer shapes, so as to select the most suitable design scheme, and achieve the goal of reducing wind resistance and engine power consumption, and reducing energy consumption.

[0030] Finally, the effect of friction needs to be considered. Friction is a factor that cannot be ignored during the driving of the vehicle, and it is closely related to the gravity of the cab itself and the calculated uplift and depression forces. The gravity of the cab is fixed, while the uplift and depression forces are affected by air flow. During driving, due to the pressure difference between the top of the cab and the chassis, a vertical force is generated, which acts together with the gravity to affect the friction between the cab and the ground. By accurately calculating the gravity of the cab itself, the uplift and depression forces, and combining the calculation formula of the friction, the friction values under different shape designs can be obtained.

[0031] In addition, it should be noted that, in the actual calculation process, in order to significantly reduce the calculation amount and effectively simplify the process, the air friction factor between the air and the three-dimensional model shell during the driving of the cab is ignored. This decision is based on the analysis and evaluation of the error of the entire cab system.

[0032] In complex fluid mechanics calculations, although there is friction between air and object shell, the friction force generated by it is very small relative to other main forces (such as frontal air resistance, pressure difference force, etc.) on the entire cab system, usually less than one thousandth. This means that even if this friction factor is considered, the correction to the final calculation result is minimal and can be ignored.

[0033] Therefore, in order to achieve higher calculation efficiency and more concise calculation process, it is decided to ignore this air friction factor in the model. Such processing not only can greatly reduce the calculation time and resource consumption, but also can make the calculation process more focused on the main factors affecting the cab wind resistance, so as to more efficiently screen out the optimal shape profile design scheme. Of course, this simplification will not have a substantial impact on the accuracy and reliability of the final result, because the reasonableness has been ensured through error analysis.

[0034] Based on the calculation and analysis results of the above aspects, the shape profile of various cabs can be comprehensively evaluated and compared. By weighing the advantages and disadvantages of different shape profiles in terms of frontal air resistance, pressure difference, and friction, the most suitable shape profile design scheme is selected. This comprehensive screening method can fully consider the influence of various factors on the cab wind resistance, so as to achieve the goal of reducing wind resistance and engine power consumption, and thus reduce the energy consumption of the vehicle, and contribute to energy saving and emission reduction in the field of transportation.

[0035] In another preferred embodiment of the present application, when calculating the frontal wind resistance FZ of the initial model, the friction between the air and the initial model is ignored.

[0036] It is worth noting that in the calculation of the frontal wind resistance of the initial model, the model is assumed to be in an idealized environment where the friction between the air and the model surface is ignored. This means that only the pressure difference caused by the direct impact of the airflow on the front of the model is considered, and the shear force formed on the surface of the model due to air viscosity or turbulence is not considered. The size of the frontal wind resistance can be estimated relatively simply. Although there is friction between the air and the object shell, the friction force it produces is very small relative to other major forces (such as frontal wind resistance, pressure difference force, etc.) on the entire cab system, usually less than one thousandth. This means that even if this friction factor is considered, the correction to the final calculation result is minimal and can be ignored.

[0037] In another preferred embodiment of the present application, the mutually parallel and equal-area planes in the initial model are referred to as equivalent planes, and the equivalent planes are excluded from subsequent wind resistance coefficient calculations.

[0038] It can be understood that first, the resistance effect of the equivalent plane under the action of the airflow has high symmetry and consistency, so the contribution to the overall wind resistance can be reasonably inferred or equivalently replaced by the calculation results of other non-equivalent planes. Second, excluding equivalent planes can reduce computational complexity and avoid repeated calculation of the same or similar resistance effects, thereby improving computational efficiency.

[0039] In another preferred embodiment of the present application, the standard plane is adjusted to be parallel to the horizontal plane, and the adjusted distance is the minimum distance between the standard plane and the horizontal plane.

[0040] It should be noted that ensuring that the standard plane is parallel to the horizontal plane reduces the influence of irrelevant variables and facilitates the selection of a more suitable three-dimensional model.

[0041] In another preferred embodiment of the present application, the air pressure interval [P sta , P sta + ε] is pre-set, and if the calculated air pressure is outside the air pressure interval, it is recorded as abnormal air pressure. Abnormal air pressure does not participate in the calculation of the lifting force and the downward pressure, where P sta represents the standard atmospheric pressure, and ε represents the pre-set pressure threshold, ε > 0.

[0042] It should be noted that excluding abnormal data reduces the influence of abnormal data on the final screening result and improves accuracy.

[0043] In another preferred embodiment of the present application, the impact surface perpendicular to the horizontal plane is referred to as the non-impact plane, and the non-impact plane does not participate in the calculation of the downward pressure.

[0044] It can be understood that in the analysis of the stress condition of the initial model, those influence planes perpendicular to the horizontal plane are defined as "non-influence planes". These planes, due to their special geometric direction, will not produce direct downward pressure effect under the action of airflow. Therefore, in order to simplify the calculation process, these non-influence planes are excluded from the calculation of downward pressure, so as not to participate in the subsequent correlation analysis. First, the non-influence plane is perpendicular to the direction of airflow, and the airflow on its surface mainly produces pressure distribution perpendicular to the plane, rather than the direction force parallel to the horizontal plane. The influence of this pressure distribution on the overall downward pressure can be ignored or replaced by the calculation results of other non-vertical planes. Second, the exclusion of non-influence planes can reduce the complexity of calculation, avoid the introduction of unnecessary variables and errors, and thus improve the calculation accuracy and efficiency. In addition, this simplification helps to focus attention on the key areas of the model that have significant downward pressure contribution, so as to more accurately evaluate the influence of these areas on the overall stress. However, it should be noted that in some specific cases, non-influence planes may have some influence on downward pressure through indirect means such as airflow around or vortex effect. Therefore, in actual application, it is necessary to carefully choose whether to exclude these planes according to specific needs, and if necessary, to carry out supplementary analysis to ensure the comprehensiveness and accuracy of the calculation results.

[0045] In another preferred embodiment of the present application, the protruding and recessed regions in the initial model are marked and the maximum height G of the protruding region and the maximum depth D of the recessed region are obtained. If it is less than the preset influence threshold YX, it is recorded as a non-influence region, and the non-influence region does not participate in the subsequent calculation of the wind resistance coefficient.

[0046] In another preferred embodiment of the present application, if there are three-dimensional models with equal wind resistance coefficients, the three-dimensional model with smaller cab front projection area is placed in the front position in the sorting.

[0047] It is worth noting that when there are three-dimensional models with equal wind resistance coefficients, in order to avoid conflicts, the three-dimensional model with smaller cab front projection area is placed in the front position in the sorting, and the three-dimensional model with smaller front wind resistance is preferred.

[0048] The above describes one embodiment of the present application in detail, but the content described is only the preferred embodiment of the present application and cannot be considered as limiting the scope of the implementation of the present application. Any equivalent changes and improvements made within the scope of the present application shall still belong to the patent coverage range of the present application.

Claims

1. A cab wind drag profile optimization method based on digital twinning, characterized by, The method comprises the following steps: S1: a three-dimensional model of the cab is established and recorded as an initial model, the initial model is made to move forward at a preset speed v, a plane in the initial model is recorded as an initial plane, an angle θ between the initial plane and a horizontal plane is obtained, and a frontal wind resistance of the initial model is calculated wherein I represents the number of initial planes, S i represents the area of the i th initial plane in the initial model, P i represents the wind pressure of the i th initial plane in the initial model, θ i represents the angle of the i th initial plane in the initial model and the horizontal plane; S2: the plane where the chassis in the initial model is recorded as the standard plane, the air flow rate Q of the standard plane is obtained, and the air pressure of the standard plane is calculated , wherein W represents a preset static pressure constant, p represents air density, H Q represents the distance between the standard plane and the horizontal plane, g represents the acceleration of gravity, and the lifting force F up =P Q S Q , S Q represents the area of the standard plane; S3: record the plane above the standard plane as the influence plane, obtain the air flow rate K of the influence plane, and calculate the air pressure of the influence plane , wherein H Q_min represents the minimum distance between the influence plane and the horizontal plane, H Q_max represents the maximum distance between the influence plane and the horizontal plane, and the down pressure is calculated , J represents the number of influence planes, P K_j represents the air pressure of the jth influence plane, S K_j represents the area of the jth influence plane, θ K_j represents the angle between the jth influence plane and the horizontal plane; S4: Calculate the friction force , μ represents the friction factor between the tire and the ground, G represents the gravity of the cab, and the wind resistance coefficient of the initial model is calculated , S represents the area of the front projection of the cab; The three-dimensional models are sorted according to the wind resistance coefficient FX from small to large, the first three-dimensional model in the sorting is recorded as the optimal model and is used as the cab wind resistance profile optimization scheme.

2. The cab wind drag profile optimization method based on digital twinning of claim 1, wherein, In the step S1, when calculating the front wind resistance FZ of the initial model, the friction between air and the initial model is ignored.

3. The cab wind drag profile optimization method based on digital twinning of claim 1, wherein, In the step S1, the parallel planes with equal areas in the initial model are recorded as equivalent planes, the equivalent planes are removed and do not participate in the subsequent wind resistance coefficient calculation.

4. The cab wind drag profile optimization method based on digital twinning of claim 1, wherein, In the step S2, the standard plane is adjusted to be parallel to the horizontal plane, and the adjusted distance is the minimum distance between the standard plane and the horizontal plane.

5. The cab wind drag profile optimization method based on digital twinning of claim 1, wherein, In the step S2, an air pressure interval [P sta , P sta + ε] is preset, and if the calculated air pressure is outside the air pressure interval, it is recorded as an abnormal air pressure, which does not participate in the calculation of the lift and the down pressure, wherein P sta represents a standard atmospheric pressure, and ε represents a preset pressure threshold, and ε > 0.

6. The cab wind drag profile optimization method based on digital twinning of claim 1, wherein, In the step S3, the impact surface perpendicular to the horizontal plane is recorded as the non-impact plane, and the non-impact plane does not participate in the calculation of the downward pressure.

7. The cab wind drag profile optimization method based on digital twinning of claim 1, wherein, In the step S4, the protruding and recessed areas in the initial model are marked, the maximum height G of the protruding area and the maximum depth D of the recessed area are obtained, and if the value is less than the preset impact threshold YX, the area is recorded as the non-impact area, and the non-impact area does not participate in the subsequent wind resistance coefficient calculation.

8. The cab wind drag profile optimization method based on digital twinning of claim 1, wherein, In the step S4, if there are three-dimensional models with equal wind resistance coefficients, the three-dimensional model with smaller cab front projection area is located in the front position in the sorting.

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