Three-dimensional trailing vortex danger area determination method based on machine type pairing under crosswind condition

Abstract

The invention discloses a method for determining a three-dimensional trailing vortex danger area based on model pairing under a crosswind condition, and relates to the technical field of fluid mechanics, and the method comprises the steps: employing an SSTk-omega turbulence model of Fluent to simulate trailing vortex evolution, determining an initial circular rector, a vortex core spacing, an initial vortex core radius and a characteristic time parameter, and setting a fluid domain and grid related parameters; and carrying out grid refinement by adopting a dynamic grid adaptive algorithm based on a vorticity value, and determining a refinement threshold value and a maximum refinement layer number. According to the method for determining the three-dimensional trailing vortex danger area based on machine type pairing under the crosswind condition, trailing vortex evolution is simulated by adopting an SSTk-omega turbulence model of Fluent, and grid refinement is carried out in combination with a dynamic grid adaptive algorithm, so that details of trailing vortex flow can be more accurately captured, the accuracy of determining the trailing vortex danger area is improved, and the accuracy of determining the trailing vortex danger area is improved. And in the trailing vortex encounter model, a strip method is adopted to calculate an induced rolling torque coefficient, and the induced rolling torque coefficient is used as a safety criterion to demarcate a trailing vortex simplified safety area.

Description

Technical Field

[0001] The invention relates to the technical field of fluid mechanics, and in particular to a method for determining a three-dimensional wake vortex danger zone based on aircraft model pairing under crosswind conditions. Background Art

[0002] In the aviation field, aircraft will generate tail vortices during takeoff, landing and cruising. Tail vortices are rotating airflows formed near the trailing edge of the wing by the downwash corresponding to the lift generated by the wing. These tail vortices maintain a certain strength and structure for a period of time and will have an impact on subsequent aircraft. Especially in the case of aircraft pairing and crosswind, the impact of tail vortices on subsequent aircraft mainly includes changes in induced rolling moment and induced speed, which may cause changes in the flight attitude of subsequent aircraft and even cause danger.

[0003] Most of the existing methods for determining the danger zone of the wake vortex are based on the condition of no crosswind. In actual flight, crosswind is a common meteorological condition. The presence of crosswind will change the evolution process of the wake vortex, causing the position and range of the danger zone of the wake vortex to change. Therefore, under the condition of crosswind, the traditional method for determining the danger zone of the wake vortex based on the condition of no crosswind may not accurately assess the impact of the wake vortex on the following aircraft.

[0004] In addition, different aircraft models have different wake vortex characteristics due to differences in their wing configuration, size, mass and other parameters. Therefore, in the case of model pairing, it is necessary to consider whether the impact of the leading aircraft's wake vortex on the trailing aircraft matches the characteristics of the trailing aircraft, so as to more accurately evaluate the wake vortex danger zone. To this end, we proposed a three-dimensional wake vortex danger zone determination method based on model pairing under crosswind conditions. Summary of the invention

[0005] In order to solve the above technical problems, a method for determining a three-dimensional wake vortex danger zone based on aircraft model pairing under crosswind conditions is provided. This technical solution solves the above problems.

[0006] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0007] The method for determining the three-dimensional wake vortex danger zone based on aircraft model pairing under crosswind conditions includes:

[0008] Fluent's SSTk-ω turbulence model is used to simulate the evolution of the wake vortex, determine the initial circulation, vortex core spacing, initial vortex core radius and characteristic time parameters, and set the fluid domain and grid related parameters;

[0009] The dynamic mesh adaptive algorithm based on vorticity value is used to refine the mesh, and the refinement threshold and the maximum number of refinement layers are determined;

[0010] The strip method is used to calculate the induced rolling moment coefficient in the wake vortex encounter model, and the rolling moment coefficient is used as a safety criterion to draw a simplified safety zone for the wake vortex.

[0011] Based on the wake vortex evolution and encounter analysis results under different crosswind intensities, the dynamic wake vortex danger zone is determined.

[0012] Preferably, the SSTk-ω turbulence model of Fluent is used to simulate the evolution of the wake vortex, determine the initial circulation, vortex core spacing, initial vortex core radius and characteristic time parameters, and set the fluid domain and grid related parameters specifically including:

[0013] Fluent's SSTk-ω turbulence model is used to simulate the evolution of the wake vortex, and the control equation consists of the RANS equation and the SSTk-ω turbulence model equation;

[0014] Assuming that the lift distribution of the aircraft is elliptical, the initial circulation of the aircraft is determined according to the aircraft mass, atmospheric density and wing configuration. The induced velocity model is formed through numerical simulation and experimental measurement, and the HB model is used to initialize the tail vortex velocity field.

[0015] The A346 aircraft in the approach phase was selected as the research object. The initial circulation, vortex core spacing, initial vortex core radius and characteristic time parameters were calculated to determine the initial vortex core position and the generated initial tail vortex velocity field. The fluid domain size was set, a uniform grid with a resolution of 1m was used, and grid adaptation was performed in the area with large vorticity values ​​near the vortex core. The upper and lower boundaries of the fluid domain were set as periodic boundaries, the left boundary was the velocity inlet, and the right boundary was the pressure outlet. The numerical time step was fixed at 0.01s.

[0016] Preferably, the SSTk-ω turbulence model includes the transport equation expressions of turbulent kinetic energy and specific dissipation rate as follows:

[0017] The equation for turbulent kinetic energy is:

[0018]

[0019] In the formula, represents the partial differential symbol, ρ represents the density of the fluid, k represents the turbulent kinetic energy, t represents time, and u j represents the component of velocity in the j direction, x j represents the component of the coordinate in the j direction, P k represents the turbulent kinetic energy generation term, β * represents the model constant, ω represents the specific dissipation rate, μ represents the molecular viscosity coefficient, μ t represents the turbulent viscosity coefficient, σ k represents the model constant related to the turbulent Prandtl number;

[0020] The equation for the specific dissipation rate is:

[0021]

[0022] In the formula, α, β, σ ω are model constants.

[0023] Preferably, the initial circulation expression is:

[0024]

[0025] b0=sB

[0026] r c =0.052b0

[0027] In the formula, Γ0 represents the initial circulation of the aircraft, g represents the acceleration of gravity, and ρ 气 represents the atmospheric density, B represents the aircraft wingspan, V represents the flight speed, MLW represents the maximum landing weight of the aircraft, b0 represents the initial vortex core spacing, s represents the wing load distribution coefficient, which is π / 4, and r c represents the initial vortex core radius;

[0028] Preferably, the calculation method of the HB model initialization tail vortex velocity field is:

[0029]

[0030]

[0031] Where V θ (r) represents the tangential induced velocity, r represents the distance from the point to the vortex core, and t0 represents the characteristic time, which means the time required for the tail vortex to drop one initial vortex core distance.

[0032] Preferably, a dynamic grid adaptive algorithm based on vorticity value is used for grid refinement, and determining the refinement threshold and the maximum number of refinement layers specifically includes:

[0033] ICEM is used to divide the fluid domain into a uniform grid with a resolution of 1 m;

[0034] The dynamic grid adaptive algorithm based on vorticity value is used for grid refinement, and the vorticity at the position of 3 times the vortex core radius after initialization is used as the refinement threshold.

[0035] A dichotomy-based refinement strategy is used to increase the grid resolution, and the maximum number of refinement levels is set to 2.

[0036] Preferably, the calculation formula of vorticity is:

[0037]

[0038]

[0039] In the formula, It represents the vorticity at the position of 3 times the vortex core radius after initialization. This value is used as the refinement threshold. Parts of the mesh will be marked for refinement. Parts of the mesh will be marked as coarsened.

[0040] Preferably, the strip method is used in the wake vortex encounter model to calculate and obtain the induced rolling moment coefficient, and the rolling moment coefficient is used as a safety criterion to draw a simplified safety zone for the wake vortex, which specifically includes:

[0041] In the wake vortex encounter model, only the influence of the vertical airflow of the wake vortex on the rolling moment generated by the later wing is considered. The strip method is used for calculation. The rolling moment of each strip is calculated according to the lift change of each strip. The rolling moment of each strip is added up and dimensionless using the model parameters to obtain the induced rolling moment coefficient.

[0042] Taking the A346 as the front aircraft and the B744 as the rear aircraft as examples, the rolling moment coefficient is used as the safety criterion, the rolling moment coefficient of each position of the tail vortex and its external area is calculated, the position range where the rolling moment coefficient is greater than the critical rolling moment coefficient is found, the simplified safety zone of the tail vortex is drawn, the safety index is determined according to the relevant flight simulation experimental data, and the rectangular boundary area of ​​the rolling moment coefficient is taken as the danger zone;

[0043] Among them, the expression of induced rolling moment coefficient is:

[0044]

[0045] Preferably, the calculation formulas for the strip lift variation and the rolling moment are:

[0046] The calculation formula of strip lift variation is:

[0047] ΔL i =0.5·ρ·c i ΔC Li ·Δy

[0048] ΔC Li =C Lα ·Δα i

[0049]

[0050] Where, ΔC Li represents the change in lift coefficient, c i represents the chord length of the strip, C Lα represents the lift line slope, Δα i represents the additional angle of attack, w iIndicates vertical induced speed, V indicates rear aircraft speed

[0051] The rolling moment calculation formula is:

[0052] ΔM i =∑ΔL i × i

[0053] Where, ΔM i Denotes the rolling moment, ΔL i Indicates lift.

[0054] Preferably, based on the wake vortex evolution and encounter analysis results under different crosswind intensities, determining the dynamic wake vortex danger zone specifically includes: analyzing the changes in the danger zone in the vertical and horizontal directions, including the danger zone shifting horizontally toward the wind direction as the crosswind intensity increases, moving upward in the vertical direction compared to when there is no wind, and the range of the wake vortex danger zone becomes smaller.

[0055] Compared with the prior art, the present invention has the following beneficial effects:

[0056] The three-dimensional wake vortex danger zone determination method based on aircraft model pairing under crosswind conditions proposed in the present invention can more accurately capture the details of the wake vortex flow by adopting Fluent's SSTk-ω turbulence model to simulate the wake vortex evolution and refine the grid in combination with the dynamic grid adaptive algorithm, thereby improving the accuracy of the wake vortex danger zone determination. The strip method is used to calculate the induced rolling moment coefficient in the wake vortex encounter model, and this is used as a safety criterion to delineate the wake vortex simplified safety zone, which provides a strong guarantee for flight safety. The wake vortex evolution and encounter situations under different crosswind intensities are taken into account, and the dynamic wake vortex danger zone can be determined, which provides an important reference basis for pilots' flight operations under crosswind conditions. It has the advantages of improving the accuracy of the wake vortex danger zone determination, ensuring flight safety, and providing a reference for the dynamic wake vortex danger zone. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0058] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0059] Reference Figure 1As shown in the figure, a method for determining a three-dimensional wake vortex danger zone based on aircraft model pairing under crosswind conditions includes: using Fluent's SSTk-ω turbulence model to simulate the evolution of the wake vortex, determining the initial circulation, vortex core spacing, initial vortex core radius and characteristic time parameters, and setting fluid domain and grid related parameters; using a dynamic grid adaptive algorithm based on vortex value to refine the grid, and determining the refinement threshold and the maximum number of refinement layers; using the strip method to calculate in the wake vortex encounter model to obtain the induced rolling moment coefficient, using the rolling moment coefficient as a safety criterion, and delineating a simplified safety zone for the wake vortex; determining the dynamic wake vortex danger zone based on the wake vortex evolution and encounter analysis results under different crosswind intensities.

[0060] Fluent's SSTk-ω turbulence model is used to simulate the evolution of the wake vortex. The governing equations consist of the Reynolds-averaged Navier-Stokes (RANS) equations and the SSTk-ω turbulence model equations. The SST turbulence model contains the transport equations for turbulent kinetic energy and specific dissipation rate:

[0061] The equation for turbulent kinetic energy is:

[0062]

[0063] In the formula, represents the partial differential symbol, ρ represents the density of the fluid, k represents the turbulent kinetic energy, t represents time, and u j represents the component of velocity in the j direction, x j represents the component of the coordinate in the j direction, P k represents the turbulent kinetic energy generation term, β * represents the model constant, ω represents the specific dissipation rate, μ represents the molecular viscosity coefficient, μ t represents the turbulent viscosity coefficient, σ k represents the model constant related to the turbulent Prandtl number;

[0064] The equation for the specific dissipation rate is:

[0065]

[0066] Where α, β, and σω all represent model constants.

[0067] Assuming that the lift distribution of the aircraft is elliptical, the initial circulation of the aircraft is mainly determined by the aircraft mass, atmospheric density, and wing configuration, which can be expressed as:

[0068]

[0069] b0=sB

[0070] r c =0.052b0

[0071] In the formula, Γ0 represents the initial circulation of the aircraft, g represents the acceleration of gravity, and ρ 气 represents the atmospheric density, B represents the aircraft wingspan, V represents the flight speed, MLW represents the maximum landing weight of the aircraft, b0 represents the initial vortex core spacing, s represents the wing load distribution coefficient, which is π / 4, and r c represents the initial vortex core radius;

[0072] The induced velocity is studied by numerical simulation and experimental measurement, and various induced velocity models are formed. The HB model has high accuracy and is used to initialize the tail vortex velocity field in this paper. The calculation method of the HB model to initialize the tail vortex velocity field is:

[0073]

[0074]

[0075] Where V θ (r) represents the tangential induced velocity, r represents the distance from the point to the vortex core, and t0 represents the characteristic time, which means the time required for the tail vortex to drop one initial vortex core distance.

[0076] The A346 in the approach phase is selected as the research object. The relevant parameters of the model are shown in Table 1. The initial circulation is calculated to be 559.1m 2 / s, the vortex core spacing is 50.6m, the initial vortex core radius is 2.6m, and the characteristic time is 28.8s. The initial vortex core position and the generated initial tail vortex velocity field are shown in Figure 1 shown.

[0077] Table 1 Model parameters

[0078]

[0079] In order to balance the calculation accuracy and speed, ICEM is first used to divide the fluid domain into uniform grids with a resolution of 1 m, and then a dynamic grid adaptive algorithm based on vorticity value is used to refine the grid. The grid is adaptively optimized after each time step to better capture the details of the vortex flow. Vorticity is the curl of the fluid velocity vector and is one of the important indicators for measuring vortex intensity. It can be expressed as:

[0080]

[0081]

[0082] In the formula, It represents the vorticity at the position of 3 times the vortex core radius after initialization. This value is used as the refinement threshold. Parts of the mesh will be marked for refinement. Some meshes will be marked as coarsened, and a dichotomy-based refinement strategy will be used to increase the mesh resolution. The maximum number of refinement levels is set to 2 to control the degree of mesh refinement.

[0083] Refine the criteria The values ​​of and the maximum number of refinement layers affect the calculation accuracy and speed. Therefore, six experimental calculations are carried out to determine the appropriate values. The velocity input model and fluid domain settings are consistent with the previous article. The vorticity at the position of 1 times, 3 times, and 5 times the vortex core radius after initialization is selected as The maximum number of refinement layers is 1 to 3, and the experimental names and parameters are shown in Table 2.

[0084] Table 2 Adaptive grid experiment parameter settings

[0085]

[0086] In the wake vortex encounter model, only the influence of the vertical airflow of the wake vortex on the rolling moment generated by the rear wing is considered, and the strip method is used for calculation. When the rear aircraft enters the wake flow field of the front aircraft, it is affected by the induced upwash and downwash airflow, and the lift of the aircraft will change. The lift change of each strip is:

[0087] ΔL i =0.5·ρ·c i ΔC Li ·Δy

[0088] ΔC Li =C Lα ·Δα i

[0089]

[0090] Where, ΔC Li represents the change in lift coefficient, c i represents the chord length of the strip, C Lα represents the lift line slope, Δα i represents the additional angle of attack, w i represents the vertical induced speed, V represents the speed of the rear aircraft, then the rolling moment of each strip is:

[0091] ΔM i =∑ΔL i × i

[0092] Where, ΔM i Denotes the rolling moment, ΔL i Indicates lift.

[0093] The rolling moment of each strip is summed up and dimensionless using the aircraft model parameters to obtain an indicator that can quantify the severity of the wake vortex encounter - the induced rolling moment coefficient, which is expressed as:

[0094]

[0095] Taking the A346 as the front aircraft and the B744 as the rear aircraft as examples, the rolling moment coefficient is used as the safety criterion, the rolling moment coefficient of each position of the tail vortex and its external area is calculated, the position range where the rolling moment coefficient is greater than the critical rolling moment coefficient is found, the simplified safety zone of the tail vortex is drawn, the safety index is determined according to the relevant flight simulation experimental data, and the rectangular boundary area of ​​the rolling moment coefficient is taken as the danger zone;

[0096] According to the results of wake vortex evolution and encounter analysis under different crosswind intensities, the dynamic wake vortex danger zone is determined, specifically including analyzing the changes of the danger zone in the vertical and horizontal directions, including that the danger zone shifts horizontally toward the wind direction as the crosswind intensity increases, moves upward in the vertical direction compared to when there is no wind, and the range of the wake vortex danger zone becomes smaller.

[0097] The use process of the present invention is as follows: using Fluent's SSTk-ω turbulence model to simulate the evolution of the wake vortex, determine relevant parameters and set the fluid domain and grid parameters; using a dynamic grid adaptive algorithm to refine the grid, determine the threshold and the number of layers; using the strip method to calculate the induced rolling moment coefficient, and using it as a safety criterion to delineate a safe zone; and determining the danger zone based on the evolution of the wake vortex and encounter analysis under different crosswinds.

[0098] To sum up, the advantages of the present invention are: a three-dimensional wake vortex danger zone determination method based on aircraft model pairing under crosswind conditions, by adopting Fluent's SSTk-ω turbulence model to simulate the evolution of the wake vortex, and combining the dynamic grid adaptive algorithm for grid refinement, can more accurately capture the details of the wake vortex flow, thereby improving the accuracy of the determination of the wake vortex danger zone, and adopt the strip method to calculate the induced rolling moment coefficient in the wake vortex encounter model, and use this as a safety criterion to delineate the simplified wake vortex safety zone, which provides a strong guarantee for flight safety, takes into account the evolution and encounter of the wake vortex under different crosswind intensities, and can determine the dynamic wake vortex danger zone, which provides an important reference basis for the pilot's flight operations under crosswind conditions, and has the advantages of improving the accuracy of the determination of the wake vortex danger zone, ensuring flight safety, and providing a reference for the dynamic wake vortex danger zone.

[0099] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for determining a three-dimensional wake vortex danger zone based on aircraft model pairing under crosswind conditions, characterized in that: include: Fluent's SSTk-ω turbulence model is used to simulate the evolution of the wake vortex, determine the initial circulation, vortex core spacing, initial vortex core radius and characteristic time parameters, and set the fluid domain and grid related parameters; A dynamic mesh adaptive algorithm based on vorticity value is used to refine the mesh, and the refinement threshold and the maximum number of refinement layers are determined; The strip method is used to calculate the induced rolling moment coefficient in the wake vortex encounter model, and the rolling moment coefficient is used as a safety criterion to draw a simplified safety zone for the wake vortex. Based on the wake vortex evolution and encounter analysis results under different crosswind intensities, the dynamic wake vortex danger zone is determined.

2. The method for determining the three-dimensional wake vortex danger zone based on aircraft model pairing under crosswind conditions according to claim 1, characterized in that: Fluent's SSTk-ω turbulence model is used to simulate the evolution of the tail vortex, determine the initial circulation, vortex core spacing, initial vortex core radius and characteristic time parameters, and set the fluid domain and grid related parameters, including: Fluent's SSTk-ω turbulence model is used to simulate the evolution of the wake vortex, and the control equation consists of the RANS equation and the SSTk-ω turbulence model equation; Assuming that the lift distribution of the aircraft is elliptical, the initial circulation of the aircraft is determined according to the aircraft mass, atmospheric density and wing configuration. The induced velocity model is formed through numerical simulation and experimental measurement, and the HB model is used to initialize the tail vortex velocity field. The A346 aircraft in the approach phase was selected as the research object. The initial circulation, vortex core spacing, initial vortex core radius and characteristic time parameters were calculated to determine the initial vortex core position and the generated initial tail vortex velocity field. The fluid domain size was set, a uniform grid with a resolution of 1m was used, and grid adaptation was performed in the area with large vorticity values ​​near the vortex core. The upper and lower boundaries of the fluid domain were set as periodic boundaries, the left boundary was the velocity inlet, and the right boundary was the pressure outlet. The numerical time step was fixed at 0.01s.

3. The method for determining the three-dimensional wake vortex danger zone based on aircraft model pairing under crosswind conditions according to claim 2 is characterized in that: The transport equation of the SSTk-ω turbulence model including turbulent kinetic energy and specific dissipation rate is expressed as: The equation for turbulent kinetic energy is: In the formula, represents the partial differential symbol, ρ represents the density of the fluid, k represents the turbulent kinetic energy, t represents time, and u j represents the component of velocity in the j direction, x j represents the component of the coordinate in the j direction, P k represents the turbulent kinetic energy generation term, β * represents the model constant, ω represents the specific dissipation rate, μ represents the molecular viscosity coefficient, μ t represents the turbulent viscosity coefficient, σ k represents the model constant related to the turbulent Prandtl number; The equation for the specific dissipation rate is: In the formula, α, β, σ ω are model constants.

4. The method for determining the three-dimensional wake vortex danger zone based on aircraft model pairing under crosswind conditions according to claim 2, characterized in that: The initial circulation expression is: b0=sB r c ＝0.052b0 In the formula, Γ0 represents the initial circulation of the aircraft, g represents the acceleration of gravity, and ρ 气 represents the atmospheric density, B represents the aircraft wingspan, V represents the flight speed, MLW represents the maximum landing weight of the aircraft, b0 represents the initial vortex core spacing, s represents the wing load distribution coefficient, which is π / 4, and r c represents the initial vortex core radius.

5. The method for determining the three-dimensional wake vortex danger zone based on aircraft model pairing under crosswind conditions according to claim 2, characterized in that: The calculation method of the initialization tail vortex velocity field of the HB model is: Where V θ (r) represents the tangential induced velocity, r represents the distance from the point to the vortex core, and t0 represents the characteristic time, which means the time required for the tail vortex to drop one initial vortex core distance.

6. The method for determining the three-dimensional wake vortex danger zone based on aircraft model pairing under crosswind conditions according to claim 1, characterized in that: The dynamic mesh adaptive algorithm based on vortex value is used for mesh refinement, and the refinement threshold and the maximum number of refinement layers are determined as follows: ICEM is used to divide the fluid domain into a uniform grid with a resolution of 1 m; The dynamic grid adaptive algorithm based on vorticity value is used for grid refinement, and the vorticity at the position of 3 times the vortex core radius after initialization is used as the refinement threshold. A dichotomy-based refinement strategy is used to increase the grid resolution, and the maximum number of refinement levels is set to 2.

7. The method for determining the three-dimensional wake vortex danger zone based on aircraft model pairing under crosswind conditions according to claim 6, characterized in that: The calculation formula of vorticity is: In the formula, It represents the vorticity at the position of 3 times the vortex core radius after initialization. This value is used as the refinement threshold. Parts of the mesh will be marked for refinement. Parts of the mesh will be marked as coarsened.

8. The method for determining a three-dimensional wake vortex danger zone based on aircraft model pairing under crosswind conditions according to claim 1, characterized in that: The strip method is used to calculate the induced rolling moment coefficient in the wake vortex encounter model. The rolling moment coefficient is used as a safety criterion to draw a simplified safety zone for the wake vortex, which includes: In the wake vortex encounter model, only the influence of the vertical airflow of the wake vortex on the rolling moment generated by the later wing is considered. The strip method is used for calculation. The rolling moment of each strip is calculated according to the lift change of each strip. The rolling moment of each strip is added up and dimensionless using the model parameters to obtain the induced rolling moment coefficient. Taking the A346 as the front aircraft and the B744 as the rear aircraft as examples, the rolling moment coefficient is used as the safety criterion, the rolling moment coefficient of each position of the tail vortex and its external area is calculated, the position range where the rolling moment coefficient is greater than the critical rolling moment coefficient is found, the simplified safety zone of the tail vortex is drawn, the safety index is determined according to the relevant flight simulation experimental data, and the rectangular boundary area of ​​the rolling moment coefficient is taken as the danger zone; Among them, the expression of the induced rolling moment coefficient is:

9. The method for determining the three-dimensional wake vortex danger zone based on aircraft model pairing under crosswind conditions according to claim 8, characterized in that: The calculation formula of strip lift change and rolling moment is: The calculation formula of strip lift variation is: ΔL i =0.5·ρ·c i ·ΔC Li ·Δy ΔC Li =C Lα ·Da i Where, ΔC Li represents the change in lift coefficient, c i represents the chord length of the strip, C Lα represents the lift line slope, Δα i represents the additional angle of attack, w i It represents the vertical induced speed, and V represents the rear aircraft speed; The rolling moment calculation formula is: ΔM i =∑ΔL i ×r i Where, ΔM i Denotes the rolling moment, ΔL i Indicates lift.

10. The method for determining a three-dimensional wake vortex danger zone based on aircraft model pairing under crosswind conditions according to claim 1, characterized in that: According to the results of wake vortex evolution and encounter analysis under different crosswind intensities, the dynamic wake vortex danger zone is determined, specifically including: analyzing the changes of the danger zone in the vertical and horizontal directions, including the danger zone shifting horizontally toward the wind direction as the crosswind intensity increases, moving upward in the vertical direction compared to when there is no wind, and the shrinking of the wake vortex danger zone.

Images