Active and passive technology combined method and system for reducing drag in turbulent flow

Abstract

The application discloses a kind of turbulent flow drag reduction method and system of active and passive technology combination.For the effect of existing single drag reduction technology is limited, downstream space keeps poorly, the application adopts the nested layout of space coincidence, micro-blowing device is opened at the trough bottom of groove, and gas is injected, and the parameter optimization of combined technology is carried out by global and downstream double-area resistance evaluation standard.Based on the flow direction blade-shaped groove and the flow direction slit micro-blowing combination turbulent boundary layer flow field experiment, the results show that the global drag reduction rate and downstream drag reduction rate of the application are all more than 12%, which is significantly higher than single groove and single blowing condition, effectively overcoming the defects of single blowing downstream failure and insufficient adaptability of groove control, and is suitable for drag reduction and energy saving design of aviation, navigation and transportation tools.

Description

Technical Field

[0001] This invention belongs to the technical field of turbulent flow control, specifically relating to a turbulent drag reduction method and system that combines active and passive technologies. Background Technology

[0002] In aviation, maritime, and vehicular transportation, energy loss due to overcoming flow resistance during transport is a significant factor affecting energy efficiency. Statistics show that a 50% reduction in aerodynamic resistance in a transport system can save approximately 7.8% of annual energy consumption. Flow resistance typically includes pressure drag, frictional drag, induced drag, and wave drag, with frictional drag caused by the viscosity between the fluid and the surface of an object being the primary source of energy loss. Therefore, effectively reducing the frictional resistance of transport vehicle surfaces using flow control technology has become an important research topic in fluid mechanics, energy and power, and transportation.

[0003] Flow control technologies can be broadly categorized into passive and active control technologies based on whether they require external energy input. Passive control technologies, such as microgrooving, can limit near-wall turbulent bursts through physical geometric constraints, effectively reducing momentum exchange between the wall and the fluid. They require no external energy input and offer advantages such as high reliability and low cost. However, their drag reduction rate is strictly limited by geometric parameters, and performance is prone to degradation when deviating from design conditions. Active control technologies, such as micro-blowing, can actively lift flow-oriented vortices and thicken the viscous sublayer by injecting low-momentum fluid into the boundary layer, thereby achieving drag reduction. However, they require a continuous external energy supply, and their control effect is localized, making it difficult to achieve sustained and effective drag reduction over long distances.

[0004] Existing research on combined drag reduction technologies largely focuses on spatially separating different technologies, such as arranging a grooved area downstream of the air blowing device. While this layout slightly increases the drag reduction rate near the joint, the efficiency decreases after the maximum drag reduction point, failing to achieve synergistic effects between active and passive technologies. In summary, existing technologies cannot fully meet the comprehensive requirements of high drag reduction rate and long-term drag reduction in practical engineering. Summary of the Invention

[0005] The present invention was made in view of the above-mentioned existing situation, and its purpose is to provide a turbulence drag reduction method and system that combines active and passive technologies. Through the nested integrated design of active and passive technologies, the synergistic effect of active air lifting and passive groove constraint is realized, solving the problems of limited effect and severe downstream space attenuation of existing single drag reduction technologies.

[0006] This invention provides a turbulence drag reduction method combining active and passive technologies, comprising the following steps: The drag characteristics and near-wall turbulence fluctuations of the target drag-reducing wall in different regions along the flow direction are obtained under uncontrolled and single-controlled conditions. The different flow directions are divided into upstream of the joint control region, the joint control region, and downstream of the joint control region. A nested layout with overlapping spaces is adopted, and a micro-blowing air wall is opened at the bottom of the trench. The micro-blowing wall region is divided into a leading edge transition zone, a middle constant zone, and a trailing edge transition zone along the flow direction. Based on the actual slit blowing phenomenon, a cubic polynomial smoothing function is used to modulate the distribution of the normal blowing velocity along the flow direction, and gas is injected into the near-wall region. The dimensionless dimensions of the trench and the blowing intensity of the micro-blowing wall are determined based on the flow field characteristics. The resistance values ​​of the flow direction in different regions are calculated, and the resistance performance of multiple regions is evaluated based on the drag reduction index to obtain an effective application scheme of combined drag reduction technology under the corresponding operating conditions. Therefore, this technical solution breaks through the limitation of spatial separation of traditional active and passive technologies, and directly integrates active air blowing into the bottom of the passive trench, so that low momentum fluid can act on the near wall area of ​​the trench, realizing the synergistic effect of air blowing lifting vortex and trench confining vortex, which not only improves the overall drag reduction effect, but also extends the downstream distance of drag reduction effect.

[0007] The step of obtaining the drag characteristics and near-wall turbulence fluctuations of the target drag-reducing wall in different regions along the flow direction under uncontrolled and single-controlled conditions specifically involves: establishing three-dimensional numerical calculation models of a benchmark ordinary non-slip wall, a single-groove wall, and a single-blowing wall, and performing flow field numerical simulation calculations on the different wall environment calculation models.

[0008] Therefore, by establishing multiple sets of comparative models, this technical solution obtained benchmark resistance data under both uncontrolled and single-controlled conditions, providing an accurate optimization benchmark for joint drag reduction design and ensuring the scientific rigor and comparability of the parameter optimization process.

[0009] The step of evaluating the multi-region drag performance based on the global drag reduction index and then back-calculating the optimization parameters of the trench and the micro-blowing air specifically involves: comparing the magnitudes of the first joint control resistance with the first single trench resistance and the first single-blowing air resistance, and comparing the magnitudes of the second joint control resistance with the second single trench resistance and the second single-blowing air resistance; when the first joint control resistance is simultaneously less than both the first single trench resistance and the first single-blowing air resistance, and the second joint control resistance is simultaneously less than both the second single trench resistance and the second single-blowing air resistance, it is determined that the current parameters of the trench and the micro-blowing air meet the design requirements; otherwise, the dimensionless parameters of the trench and the micro-blowing air are back-calculated, and the parameters of the trench and the micro-blowing air are adjusted based on the optimal parameter selection range of a single control method, and the above steps are repeated; Wherein, the first joint control resistance is the resistance of the entire watershed under joint control, the first single-groove resistance is the resistance of the entire watershed under single-groove control, and the first single-blowing resistance is the resistance of the entire watershed under single-blowing control; the second joint control resistance is the resistance downstream of the joint control area under the joint control, the second single-groove resistance is the resistance downstream of the joint control area under the single-groove control, and the second single-blowing resistance is the resistance downstream of the joint control area under the single-blowing control.

[0010] Therefore, by establishing optimization criteria for both the global and downstream regions, this technical solution ensures that the combined drag reduction system not only has a better drag reduction effect in the global flow domain, but also effectively overcomes the downstream failure defect of the single blowing technology, thus achieving the technical goal of long-term drag reduction.

[0011] The step of extracting the resistance values ​​of the flow direction to different regions specifically involves: performing transient numerical calculations using the large eddy simulation method; after the flow field has fully developed and reached a statistical steady state, averaging the flow field data over time and space, and calculating the resistance values ​​upstream of the joint control region, the joint control region, and downstream of the joint control region, respectively.

[0012] Therefore, this technical solution uses the large eddy simulation method to accurately capture the transient evolution characteristics of turbulence in the near-wall region and obtain drag data, providing a reliable basis for the design of combined drag reduction schemes.

[0013] The present invention also provides a turbulence drag reduction system combining active and passive technologies, comprising: The drag-reducing wall surface is provided with grooves, and a micro-blowing wall surface is provided at the bottom of the groove. A flow field simulation device is used to obtain the drag characteristics and near-wall turbulence fluctuations of the target drag reduction wall in different regions along the flow direction under uncontrolled, single-controlled, and combined active and passive technology control conditions. The different flow directions are divided into upstream of the joint control region, the joint control region, and downstream of the joint control region. The data processing and optimization device, connected to the flow field simulation device, is used to determine the dimensionless dimensions of the trench and the blowing intensity of the micro-blowing wall based on the flow field characteristics, extract the resistance values ​​of different regions of the flow direction, evaluate the resistance performance of multiple regions based on the drag reduction index, and obtain an effective application scheme of combined drag reduction technology under the corresponding working conditions. It also includes an air blowing control device connected to the micro-blowing wall, used to divide the air blowing along the flow direction into a leading edge transition zone, a middle constant zone, and a trailing edge transition zone. The air blowing control device, based on the actual slit blowing scheme, smoothly accelerates the air blowing speed in the leading edge transition zone from zero to the maximum normal air blowing speed, maintains the air blowing speed in the middle constant zone at a constant speed, and smoothly decays the air blowing speed in the trailing edge transition zone from the maximum normal air blowing speed to zero.

[0014] Therefore, this technical solution avoids non-physical numerical oscillations and abrupt changes in the flow field caused by the step speed of the air outlet through segmented speed modulation, objectively restores the physical characteristics of the gradual seepage of airflow in micropores, ensures the reliability and accuracy of the numerical simulation data of the joint control flow field, and improves the stability of the drag reduction effect in practical applications.

[0015] The data processing and optimization device includes a determination unit, which compares the magnitudes of the first joint control resistance with the first single-groove resistance and the first single-blowing resistance, and compares the magnitudes of the second joint control resistance with the second single-groove resistance and the second single-blowing resistance. Based on the comparison results, the determination unit determines whether the current parameters of the groove and micro-blowing meet the design requirements or adjusts the parameters. The first joint control resistance is the resistance of the entire flow area under joint control, the first single-groove resistance is the resistance of the entire flow area under single-groove control, and the first single-blowing resistance is the resistance of the entire flow area under single-blowing control. The second joint control resistance is the resistance downstream of the joint control area under the joint control, the second single-groove resistance is the resistance downstream of the joint control area under the single-groove control, and the second single-blowing resistance is the resistance downstream of the joint control area under the single-blowing control.

[0016] Therefore, this technical solution achieves accurate evaluation of drag reduction effect through the judgment unit, thereby improving the system design efficiency.

[0017] The flow field simulation device establishes three-dimensional numerical calculation models of a benchmark ordinary non-slip wall, a single-groove wall, a single-blowing wall, and a groove micro-blowing groove wall. It then performs flow field numerical simulation calculations on the different wall environment calculation models to obtain the resistance characteristics and near-wall turbulence pulsation laws under the uncontrolled state, the single-controlled state, and the combined active and passive technology control state.

[0018] Therefore, this technical solution obtained accurate benchmark data through the flow field simulation device, providing a scientific basis for the optimization of system parameters.

[0019] The data processing and optimization device uses the large eddy simulation method for transient numerical calculations. After the flow field has fully developed and reached a statistical steady state, the flow field data is averaged in time and space to calculate the resistance values ​​upstream of the joint control region, the joint control region, and downstream of the joint control region, respectively.

[0020] Therefore, this technical solution obtains flow field data through large eddy simulation, ensuring the accuracy and reliability of parameter optimization results. Attached Figure Description

[0021] Figure 1 shows a flowchart of the technical implementation of the turbulence drag reduction method combining active and passive technologies of the present invention; Figure 2 shows a schematic diagram of a traditional continuous blade type single groove. Figure 3 shows a schematic diagram of a conventional non-slip wall single-air blowing structure; Figure 4 shows a schematic diagram of the combined drag reduction structure based on trenching and air blowing according to the present invention; Figure 5 shows a schematic diagram of the flow direction region division for resistance monitoring in the simulation experiment; Figure 6 shows the near-wall instantaneous vortex structure (using the Q-vortex identification criterion and velocity coloring). Detailed Implementation

[0022] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same reference numerals are used for the same parts, and repeated descriptions are omitted. Furthermore, the drawings are merely schematic diagrams, and the proportions of the parts or the shapes of the parts may differ from the actual figures.

[0023] This invention provides a method and system for turbulent drag reduction that combines active and passive technologies. Through a coupling mechanism of air blowing for lifting and channel flow stabilization, it solves the problems of limited drag reduction rate and severe downstream space attenuation in existing single-wall drag reduction technologies. The following detailed description is provided in conjunction with each of the claims.

[0024] In this embodiment, the turbulent drag reduction method combining active and passive technologies provided by the present invention first performs the step of acquiring basic flow field characteristics and benchmark drag data. Turbulent channel flow is selected as the basic verification environment, and three sets of comparative three-dimensional numerical calculation models are established using a flow field simulation device: a benchmark ordinary no-slip wall channel flow model, a single-channel model, and a single-blowing model. Flow field numerical simulation calculations are performed on the target drag reduction wall environment to accurately obtain the drag characteristics and near-wall turbulent fluctuation patterns of different regions along the flow direction of the wall under both uncontrolled and single-controlled conditions. The different flow direction regions are divided into the upstream of the joint control region, the joint control region, and the downstream of the joint control region, as shown in Figure 5.

[0025] Furthermore, the integrated combined structure design steps are implemented. Breaking through the limitations of traditional active and passive technology with spatial separation, a nested layout with overlapping spaces is adopted. Local flow-directing micro-blowing slits are directly opened at the bottom of the continuous blade-shaped grooves, as shown in Figure 4. Comparing the traditional single-groove structure shown in Figure 2 and the traditional single-blowing structure shown in Figure 3, the combined configuration of this invention enables low-momentum fluid to act on the near-wall region of the groove, achieving a combined effect of active air lifting and passive groove constraint.

[0026] Further, the step of regulating the blowing speed is performed. The flow direction of the micro-blowing slit is divided into a leading edge transition zone, a middle constant zone, and a trailing edge transition zone. Based on the actual slit blowing phenomenon, a cubic polynomial smoothing function is used to regulate the distribution of the normal blowing speed along the flow direction, and gas is injected into the near-wall region at a micro-flow rate.

[0027] Further, the steps of resistance extraction and parameter optimization are performed. Resistance values ​​for different flow regions are extracted, and the resistance performance in multiple regions is evaluated based on drag reduction indices to determine an effective application scheme for combined drag reduction technologies under corresponding operating conditions. Understandably, the core breakthrough of this invention lies in constructing a novel spatially coupled configuration for active and passive flow control technology. Its fundamental innovation lies in the precise placement of the airflow within the troughs of the microgrooves. Based on this structural layout, active and passive control mechanisms achieve deep physical synergy. This configuration enables the geometric constraint effect of the microgrooves on turbulent initiation and the injection mechanism of the airflow to function simultaneously within the same spatial domain. This not only effectively suppresses the rapid decay of the control effect downstream but also breaks through the limitations of traditional separate layouts, ultimately achieving a more significant and sustained comprehensive drag reduction effect.

[0028] In this embodiment, the main flow field of the channel is driven by a constant mass flow rate, and the reference velocity of the main flow field is the cross-sectional average velocity. The blowing system employs minute active control, setting the maximum blowing normal velocity. It is 2% of the average velocity of the mainstream cross-section. The flow-direction effect range of the blowing slit is defined as from... to Transition section length The standard setting is 0.278mm.

[0029] The specific formula for modulating the blowing speed based on the actual slit blowing phenomenon is as follows: Leading edge transition zone ( ): The blowing speed smoothly accelerates from zero to The formula is:

[0030] Among them, the dimensionless local flow direction parameter .

[0031] Central constant region ( The blowing speed remains constant, and the formula is:

[0032] Trailing edge transition zone ( ): Blowing speed from The formula for smooth decay to zero is:

[0033] Among them, the dimensionless local flow direction parameter .

[0034] Meanwhile, to ensure the conservation of mass flow rate throughout the computational domain, intake slits of the same size and velocity distribution are installed at the same location on the opposite side wall. This segmented velocity modulation effectively avoids non-physical numerical oscillations caused by velocity steps at the air inlet, ensuring the accuracy of the flow field simulation and forming an organic whole with the nested layout of the slits at the bottom of the trough.

[0035] In this embodiment, a baseline ordinary non-slip wall model is established to obtain the drag characteristics under uncontrolled conditions; a single-blade grooved wall model is used to obtain the drag characteristics under a single passive control condition; and a single local blowing wall model is used to obtain the drag characteristics under a single active control condition. Through numerical simulations of these three baseline models, an optimization benchmark for the joint drag reduction design is obtained, ensuring the scientific validity and comparability of the subsequent parameter optimization process.

[0036] In this embodiment, a dual-region evaluation system, encompassing both global and downstream regions, is adopted: The first joint control resistance is the resistance of the entire watershed under joint control, the first single trench resistance is the resistance of the entire watershed under single trench control, and the first single air blowing resistance is the resistance of the entire watershed under single air blowing control. The second joint control resistance is the resistance downstream of the joint control area under the joint control condition; the second single groove resistance is the resistance downstream of the joint control area under the single groove control condition; and the second single air blowing resistance is the resistance downstream of the joint control area under the single air blowing control condition.

[0037] The current parameters are deemed to meet design requirements only when the first combined control resistance is simultaneously less than both the first single-groove resistance and the first single-blowing resistance, and the second combined control resistance is simultaneously less than both the second single-groove resistance and the second single-blowing resistance. This dual-standard system ensures that the system not only has a superior drag reduction effect globally, but also effectively overcomes the downstream failure defects of single-blowing technology.

[0038] In this embodiment, the Large Eddy Simulation (LES) method is used to perform multiple transient numerical calculations on the four sets of operating conditions. After the flow field has fully developed and reached a statistical steady state, the flow field data is averaged in time and space, and the drag values ​​upstream, downstream, and in the joint control region are calculated respectively. The LES method can accurately capture the transient evolution characteristics of turbulence in the near-wall region, as shown in Figure 6, providing a high-fidelity data foundation for drag calculation.

[0039] Based on the above method, the comparison of multi-region drag reduction results obtained in this embodiment is shown in Table 1: Table 1 Comparison of drag reduction results in multiple regions

[0040] As shown in Table 1, the combined air-blowing and trench control model exhibits the best global drag reduction performance, with a global drag reduction rate of approximately 12%, significantly higher than the single-trench model and the single-blowing model. Spatially, the single-blowing model demonstrates a very strong local drag reduction effect within the core control region, but the downstream drag reduction effect rapidly diminishes. In contrast, the micro-grooves in the combined control model effectively suppress the surges in flow-direction and normal velocity fluctuations and Reynolds shear stress, effectively modulating the turbulent coherent structure within the flow field boundary layer. This weakens the turbulence enhancement effect caused by air-blowing in the downstream flow field, achieving an effective and sustained combined drag reduction effect. Specifically, the downstream drag reduction rate in the combined control region exceeds 12%, higher than the single-trench model and the single-blowing model, achieving the technical goal of long-term drag reduction.

[0041] The present invention also provides a turbulence drag reduction system combining active and passive technologies, including drag reduction walls, a flow field simulation device, and a data processing and optimization device.

[0042] The drag-reducing wall surface is provided with grooves, and micro-blowing is provided at the bottom of the groove valleys. This is the core physical structure for achieving active and passive coordinated drag reduction. The flow field simulation device is used to acquire baseline flow field data and joint control flow field data; The data processing and optimization device is connected to the flow field simulation device and is used for parameter determination, resistance extraction and parameter optimization.

[0043] Through the coordinated operation of various devices, the system achieves integrated design and refined control of active and passive drag reduction.

[0044] In this embodiment, the determination function and resistance extraction function of the data processing and optimization device are implemented in the same way and with the same effect as the turbulence drag reduction method combining active and passive technologies provided by the present invention, and will not be described in detail here.

[0045] The embodiments described above do not constitute a limitation on the scope of protection of this technical solution. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the above embodiments should be included within the scope of protection of this technical solution.

Claims

1. A turbulence drag reduction method combining active and passive technologies, characterized in that, Includes the following steps: The drag characteristics and near-wall turbulence fluctuations of the target drag-reducing wall in different regions along the flow direction are obtained under uncontrolled and single-controlled conditions. The different flow directions are divided into upstream of the joint control region, the joint control region, and downstream of the joint control region. A nested layout with overlapping spaces is adopted, and a micro-blowing air wall is opened at the bottom of the trench, and gas is injected into the near-wall area through the micro-blowing air wall. The dimensionless dimensions of the trench and the blowing intensity of the micro-blowing wall are determined based on the flow field characteristics. Extract the resistance values ​​of the flow direction in different regions, evaluate the resistance performance of multiple regions according to the drag reduction index, and obtain an effective application scheme of combined drag reduction technology under the corresponding working conditions. The blowing system employs a small amount of active control, setting the maximum normal blowing speed. The flow direction effect range of the blowing slit is defined as 2% of the average velocity of the main flow field section, and the flow direction effect range is defined as from... to Transition section length The standard setting is 0.278mm. The formula for regulating the blowing speed is as follows: The leading edge transition zone is The blowing speed is smoothly accelerated from zero to... The formula is: Among them, the dimensionless local flow direction parameter ; The central constant region is The blowing speed is kept constant, and the formula is: The trailing edge transition zone is The blowing speed is from The formula for smooth decay to zero is: Among them, the dimensionless local flow direction parameter .

2. The turbulence drag reduction method combining active and passive technologies according to claim 1, characterized in that, The steps for obtaining the drag characteristics and near-wall turbulence fluctuations of the target drag-reducing wall in different regions along the flow direction under uncontrolled and single-controlled conditions are as follows: establishing three-dimensional numerical calculation models of a benchmark ordinary non-slip wall, a single-groove wall, and a single-blowing wall, and performing flow field numerical simulation calculations on the environment of the target drag-reducing wall.

3. The turbulence drag reduction method combining active and passive technologies according to claim 1, characterized in that, The steps of adopting a spatially overlapping nested layout, opening a micro-blowing air wall at the bottom of the trench, and injecting gas into the near-wall area through the micro-blowing air wall are as follows: establishing a combined active and passive technology control calculation model, opening a micro-blowing air wall at the bottom of the trench, and performing numerical simulation calculations.

4. The turbulence drag reduction method combining active and passive technologies according to claim 1, characterized in that, The step of extracting the resistance values ​​of the flow direction to different regions specifically involves: using the large eddy simulation method to perform transient numerical calculations; after the flow field has fully developed and reached a statistical steady state, averaging the flow field data over time and space, and calculating the resistance values ​​upstream of the joint control region, the joint control region, and downstream of the joint control region, respectively.

5. The turbulence drag reduction method combining active and passive technologies according to claim 1, characterized in that, The steps of extracting the resistance values ​​of the flow direction in different regions, evaluating the resistance performance of multiple regions based on the drag reduction index, and obtaining an effective application scheme of the combined drag reduction technology under the corresponding working conditions are as follows: Specifically, the magnitudes of the first joint control resistance, the first single groove resistance, and the first single air blowing resistance are compared; and the magnitudes of the second joint control resistance, the second single groove resistance, and the second single air blowing resistance are compared. When the first joint control resistance is simultaneously less than both the first single groove resistance and the first single air blowing resistance, and the second joint control resistance is simultaneously less than both the second single groove resistance and the second single air blowing resistance, it is determined that the parameters of the groove and air blowing meet the design requirements; otherwise, the quantity of the groove and air blowing is calculated. Based on the optimal parameter selection range of a single control method, the parameters of the trench and the air blowing are adjusted and the above steps are repeated; wherein, the first joint control resistance is the resistance of the global flow area under joint control, the first single trench resistance is the resistance of the global flow area under single trench control, and the first single air blowing resistance is the resistance of the global flow area under single air blowing control; the second joint control resistance is the resistance downstream of the joint control area under the joint control, the second single trench resistance is the resistance downstream of the joint control area under the single trench control, and the second single air blowing resistance is the resistance downstream of the joint control area under the single air blowing control.

6. A turbulence drag reduction system combining active and passive technologies, used to implement the method described in any one of claims 1-5, characterized in that, include: The drag-reducing wall surface is provided with grooves, and a micro-blowing wall surface is provided at the bottom of the groove. A flow field simulation device is used to obtain the drag characteristics and near-wall turbulence fluctuations of the target drag reduction wall in different regions along the flow direction under uncontrolled, single-controlled, and combined active and passive technology control conditions. The different flow directions are divided into upstream of the joint control region, the joint control region, and downstream of the joint control region. The data processing and optimization device, connected to the flow field simulation device, is used to determine the dimensionless dimensions of the trench and the blowing intensity of the micro-blowing wall based on the flow field characteristics, extract the resistance values ​​of different regions of the flow direction, evaluate the resistance performance of multiple regions based on the drag reduction index, and obtain an effective application scheme of combined drag reduction technology under the corresponding working conditions.

7. The turbulence drag reduction system combining active and passive technologies according to claim 6, characterized in that, It also includes an air blowing control device connected to the micro-blowing wall, used to divide the air blowing along the flow direction into a leading edge transition zone, a middle constant zone, and a trailing edge transition zone. The air blowing control device, based on the actual slit blowing scheme, smoothly accelerates the air blowing speed in the leading edge transition zone from zero to the maximum normal air blowing speed, maintains the air blowing speed in the middle constant zone at a constant speed, and smoothly decays the air blowing speed in the trailing edge transition zone from the maximum normal air blowing speed to zero.

8. The turbulence drag reduction system combining active and passive technologies according to claim 6, characterized in that, The data processing and optimization device includes a determination unit, which is used to compare the magnitudes of the first joint control resistance with the first single-groove resistance and the first single-blowing resistance, and to compare the magnitudes of the second joint control resistance with the second single-groove resistance and the second single-blowing resistance, and to determine whether the current parameters of the groove and the micro-blowing meet the design requirements or to adjust the parameters based on the comparison results; wherein, the first joint control resistance is the resistance of the global flow area under joint control, the first single-groove resistance is the resistance of the global flow area under single-groove control, and the first single-blowing resistance is the resistance of the global flow area under single-blowing control; the second joint control resistance is the resistance downstream of the joint control area under the joint control, the second single-groove resistance is the resistance downstream of the joint control area under the single-groove control, and the second single-blowing resistance is the resistance downstream of the joint control area under the single-blowing control.

9. The turbulence drag reduction system combining active and passive technologies according to claim 6, characterized in that, The data processing and optimization device uses the large eddy simulation method for transient numerical calculations. After the flow field has fully developed and reached a statistical steady state, the flow field data of the established benchmark ordinary non-slip wall, single groove wall, single blowing wall, and three-dimensional numerical calculation model of active and passive technology combination control are averaged in time and space to calculate the resistance values ​​upstream of the joint control area, the joint control area, and the downstream of the joint control area, respectively.

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