Flight simulation method and device under gust load considering downwash effect

Abstract

The invention belongs to the technical field of aircraft simulation, and relates to a flight simulation method and device under gust load considering a downwash effect. The method comprises the following steps: S1, carrying out 1g level flight balancing on the aircraft, and determining a balancing attack angle of the aircraft and a balancing elevator skewness of the aircraft; s2, superposing the aerodynamic coefficient increment brought by the downwash angle of attack to the aerodynamic coefficient of the aircraft body, and determining the aerodynamic force of the aircraft; s3, dynamic response solving is conducted on aerodynamic force of the aircraft, the flight speed is obtained, the corrected speed of the aircraft is determined after the flight speed is superposed with the wind speed of the vertical gust field, and the aerodynamic attack angle and the flight Mach number are determined according to the corrected speed; and S4, re-determining the aerodynamic force of the aircraft according to the flight Mach number, the pitch angle speed, the aerodynamic angle of attack, the given wind speed of the vertical gust field and the elevator skewness, and circulating the steps until the simulation is finished. The method is simple in simulation process and high in precision, and meets the requirements of engineering practice.

Description

Technical Field

[0001] The present application belongs to the technical field of aircraft simulation, and in particular, relates to a flight simulation method and device under gust loads taking into account downwash effects. Background Art

[0002] In traditional aircraft flight load design, the aircraft is usually in free flow, and the aircraft as a whole is not affected by the downwash of other objects. When there are other large aircraft in front of the aircraft, the aircraft behind will be affected by the downwash of the aircraft in front, which will change the aerodynamic characteristics of the entire aircraft and the distribution of aerodynamic loads. The downwash effect needs to be considered in the flight load design.

[0003] The downwash generated by the front aircraft is a relatively complex aerodynamic interference, which is related to the flight speed, flight attitude, and spatial relative relationship of the front and rear aircraft. When this downwash effect is strong, it will significantly affect the flight load and flight safety of the rear aircraft. Therefore, it is necessary to establish a method for determining the aircraft gust load considering the downwash effect to meet the needs of engineering practice. Summary of the invention

[0004] In order to solve the above problems, the first aspect of the present application provides a flight simulation method under gust load considering downwash effect, which mainly includes:

[0005] Step S1, performing level flight trim of the aircraft 1g, determining the trim angle of attack of the aircraft and the trim elevator deflection of the aircraft, which are used as the initial aerodynamic angle of attack and elevator deflection of the simulation;

[0006] Step S2, adding the aerodynamic coefficient increment caused by the downwash angle of attack to the aerodynamic coefficient of the aircraft body to obtain an aerodynamic coefficient correction value, and determining the aerodynamic force of the aircraft according to the aerodynamic coefficient correction value;

[0007] Step S3, solving the dynamic response of the aerodynamic force of the aircraft to obtain the flight speed, superimposing the flight speed with the wind speed of the vertical gust field to determine the corrected speed of the aircraft, and determining the aerodynamic angle of attack and the flight Mach number according to the corrected speed;

[0008] Step S4, according to the flight Mach number, pitch angular velocity, aerodynamic angle of attack, the wind speed of the given vertical gust field and the given elevator deflection, return to step S2, re-determine the aerodynamic force of the aircraft and loop the above steps until the simulation ends.

[0009] Preferably, step S1 further comprises:

[0010] S11, obtaining input aircraft flight speed V, flight altitude H, aircraft mass m and aircraft aerodynamic characteristics data set;

[0011] S12, calculating the atmospheric density ρ at the flight altitude H, and further calculating the velocity pressure Q of the aircraft;

[0012] S13. Perform 1g trim on the aircraft based on the above parameters to obtain the trim angle of attack and the trim elevator deflection of the aircraft.

[0013] Preferably, in step S12, the speed pressure Q of the aircraft is calculated by the following formula:

[0014] Q=0.5ρV.

[0015] Preferably, step S2 further comprises:

[0016] Step S21: interpolate the aerodynamic characteristic data set of the aircraft body to obtain the drag coefficient C of the aircraft under the current aerodynamic angle of attack and elevator deflection conditions. D , lift coefficient C L , pitch moment coefficient C my and pitch damping coefficient C mq ;

[0017] Step S22, interpolating the data set consisting of the aerodynamic characteristic data of the aircraft body and the downwash angle of attack to obtain the downwash aerodynamic coefficient increment;

[0018] Step S23: The drag coefficient C of the aircraft D , lift coefficient C L , pitch moment coefficient C my and pitch damping coefficient C mq Based on the aerodynamic coefficient increment, the aerodynamic drag D, lift L and pitch moment m of the aircraft are calculated. y .

[0019] Preferably, in step S21, the drag coefficient C of the aircraft is interpolated by the following formula: D , lift coefficient C L , pitch moment coefficient C my and pitch damping coefficient C mq :

[0020]

[0021] Among them, the drag coefficient C of the aircraft is interpolated according to the flight Mach number Ma, the aerodynamic angle of attack α and the elevator deflection δe D , lift coefficient C L , pitch moment coefficient C my , according to the flight Mach number Ma, the aircraft trim angle of attack α interpolation pitch damping coefficient C mq ;

[0022] In step S22, the downwash aerodynamic coefficient increment is obtained by interpolation through the following formula:

[0023]

[0024] Among them, according to the flight Mach number Ma, aerodynamic angle of attack α and downwash angle of attack Interpolate the drag coefficient increment of the aircraft Lift coefficient increment Pitch moment coefficient increment

[0025] In step S23, the aerodynamic drag D, lift L and pitch moment m of the aircraft are calculated according to the following formula: y :

[0026]

[0027] Among them, Q is the velocity pressure of the aircraft, S is the reference area of ​​the aircraft, q is the pitch angular velocity of the aircraft, V is the flight speed of the aircraft, and c is the average aerodynamic chord length.

[0028] Preferably, step S3 further comprises:

[0029] Step S31, using the fourth-order Runge-Kutta method to solve the dynamic response of the aircraft, and obtain the projection value of the aircraft velocity on the X-axis and Z-axis of the body axis system, the pitch angle and the pitch angular velocity;

[0030] Step S32, superimposing the aircraft velocity with the wind speed of the vertical gust field to update the aircraft velocity component;

[0031] Step S33: determining a new aerodynamic angle of attack α and a flight Mach number Ma based on the updated velocity components of the aircraft.

[0032] Preferably, in step S31, the dynamic response is solved by the following formula:

[0033]

[0034] Where m is the mass of the aircraft; g is the acceleration of gravity; u and w are the projection values ​​of the aircraft velocity on the X-axis and Z-axis of the body axis system respectively; θ is the pitch angle of the aircraft; I yy is the inertia moment of the aircraft relative to the Y axis of the body axis system;

[0035] F xf is the projection value of the aerodynamic force on the X-axis of the body axis system and the projection value of the engine thrust on the X-axis of the body axis system T The sum of zf is the projection value of the aerodynamic force on the Z axis of the body axis system and the projection value of the engine thrust on the Z axis of the body axis system T The sum of yf is the moment of aerodynamic force on the Y axis of the body axis system m yThe moment m of the engine thrust on the Y axis of the body axis system T The calculation formula is as follows:

[0036]

[0037] In step S32, the velocity component of the aircraft is updated by the following formula:

[0038]

[0039] Among them, u g is the vertical gust field wind speed at the current moment;

[0040] In step S33, the new aerodynamic angle of attack α and the flight Mach number Ma are determined by the following formula:

[0041]

[0042] The second aspect of the present application provides a flight simulation device under gust load considering downwash effect, mainly comprising:

[0043] The parameter initialization module is used to perform 1g level flight trim of the aircraft, determine the trim angle of attack of the aircraft and the trim elevator deflection of the aircraft, as the initial aerodynamic angle of attack and elevator deflection of the simulation;

[0044] an aerodynamic force calculation module, for superimposing the aerodynamic force coefficient increment caused by the downwash angle of attack onto the aerodynamic force coefficient of the aircraft body to obtain an aerodynamic force coefficient correction value, and determining the aerodynamic force of the aircraft according to the aerodynamic force coefficient correction value;

[0045] A dynamic response solving module is used to solve the dynamic response of the aerodynamic force of the aircraft, obtain the flight speed, determine the corrected speed of the aircraft after superimposing the flight speed on the wind speed of the vertical gust field, and determine the aerodynamic angle of attack and the flight Mach number according to the corrected speed;

[0046] The parameter updating module is used to redetermine the aerodynamic force of the aircraft according to the flight Mach number, the pitch angular velocity, the aerodynamic angle of attack, the wind speed of the given vertical gust field and the given elevator deflection.

[0047] Preferably, the parameter initialization module includes:

[0048] A flight parameter acquisition unit, used to acquire input aircraft flight speed V, flight altitude H, aircraft mass m and aircraft aerodynamic characteristics data set;

[0049] The speed pressure calculation unit is used to calculate the atmospheric density ρ at the flight altitude H, and further calculate the speed pressure Q of the aircraft;

[0050] The trimming unit is used to perform 1g trim on the aircraft based on the above parameters to obtain the trim angle of attack and the trim elevator deflection of the aircraft.

[0051] Preferably, in the speed pressure calculation unit, the speed pressure Q of the aircraft is calculated by the following formula:

[0052] Q=0.5ρV.

[0053] Preferably, the aerodynamic force calculation module comprises:

[0054] The first interpolation unit is used to interpolate the aerodynamic characteristic data set of the aircraft body to obtain the drag coefficient C of the aircraft under the current aerodynamic angle of attack and elevator deflection conditions. D , lift coefficient C L , pitch moment coefficient C my and pitch damping coefficient C mq ;

[0055] A second interpolation unit is used to interpolate the aerodynamic characteristic data of the aircraft body and the downwash angle of attack to obtain the downwash aerodynamic coefficient increment;

[0056] Aerodynamic parameter calculation unit, used to calculate the drag coefficient C of the aircraft D , lift coefficient C L , pitch moment coefficient C my and pitch damping coefficient C mq Based on the aerodynamic coefficient increment, the aerodynamic drag D, lift L and pitch moment m of the aircraft are calculated. y .

[0057] Preferably, in the first interpolation unit, the drag coefficient C of the aircraft is interpolated by the following formula: D , lift coefficient C L , pitch moment coefficient C my and pitch damping coefficient C mq :

[0058]

[0059] Among them, the drag coefficient C of the aircraft is interpolated according to the flight Mach number Ma, the aerodynamic angle of attack α and the elevator deflection δe D , lift coefficient C L , pitch moment coefficient C my , according to the flight Mach number Ma, the aircraft trim angle of attack α interpolation pitch damping coefficient C mq ;

[0060] In the second interpolation unit, the downwash aerodynamic coefficient increment is obtained by interpolation using the following formula:

[0061]

[0062] Among them, according to the flight Mach number Ma, aerodynamic angle of attack α and downwash angle of attack Interpolate the drag coefficient increment of the aircraft Lift coefficient increment Pitch moment coefficient increment

[0063] In the aerodynamic parameter calculation unit, the aerodynamic drag D, lift L and pitch moment m of the aircraft are calculated according to the following formula: y :

[0064]

[0065] Among them, Q is the velocity pressure of the aircraft, S is the reference area of ​​the aircraft, q is the pitch angular velocity of the aircraft, V is the flight speed of the aircraft, and c is the average aerodynamic chord length.

[0066] Preferably, the dynamic response solving module includes:

[0067] The dynamic response solving unit is used to solve the dynamic response of the aircraft by using the fourth-order Runge-Kutta method to obtain the projection value of the aircraft velocity on the X-axis and Z-axis of the body axis system, the pitch angle and the pitch angle velocity;

[0068] A velocity updating unit, used to superimpose the aircraft velocity on the wind speed of the vertical gust field to update the aircraft velocity component;

[0069] The longitudinal maneuvering load calculation unit is used to determine the new aerodynamic angle of attack α and the flight Mach number Ma based on the updated aircraft velocity components.

[0070] Preferably, in the dynamic response solving unit, the dynamic response is solved by the following formula:

[0071]

[0072] Where m is the mass of the aircraft; g is the acceleration of gravity; u and w are the projection values ​​of the aircraft velocity on the X-axis and Z-axis of the body axis system respectively; θ is the pitch angle of the aircraft; I yy is the inertia moment of the aircraft relative to the Y axis of the body axis system;

[0073] F xf is the projection value of the aerodynamic force on the X-axis of the body axis system and the projection value of the engine thrust on the X-axis of the body axis system T The sum of zf is the projection value of the aerodynamic force on the Z axis of the body axis system and the projection value of the engine thrust on the Z axis of the body axis system T The sum of yf is the moment of aerodynamic force on the Y axis of the body axis system m yThe moment m of the engine thrust on the Y axis of the body axis system T The calculation formula is as follows:

[0074]

[0075] In the velocity update unit, the velocity component of the aircraft is updated by the following formula:

[0076]

[0077] Among them, u g is the vertical gust field wind speed at the current moment;

[0078] In the longitudinal maneuvering load calculation unit, the new aerodynamic angle of attack α and the flight Mach number Ma are determined by the following formula:

[0079]

[0080] A third aspect of the present application provides a computer device, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the flight simulation method under gust loads taking into account downwash as described above.

[0081] This application reasonably considers the role of downwash effect in the process of determining the aircraft gust load. The simulation process is simple and accurate, meeting the needs of engineering practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0082] Figure 1 It is a flow chart of a preferred embodiment of the flight simulation method under gust load considering downwash effect of the present application.

[0083] Figure 2 This application Figure 1 A time history graph of vertical gust wind speed for the illustrated embodiment. DETAILED DESCRIPTION

[0084] In order to make the purpose, technical scheme and advantages of the implementation of this application clearer, the technical scheme in the implementation of this application will be described in more detail in combination with the drawings in the implementation of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described implementation is a part of the implementation of this application, not all of the implementations. The implementation described below with reference to the drawings is exemplary and is intended to be used to explain this application, and cannot be understood as a limitation on this application. Based on the implementation in this application, all other implementations obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The implementation of this application is described in detail below in combination with the drawings.

[0085] The first aspect of the present application provides a flight simulation method under gust loads taking into account downwash effects, such as Figure 1 As shown, it mainly includes:

[0086] Step S1, perform level flight trim of the aircraft 1g, determine the trim angle of attack of the aircraft and the trim elevator deflection of the aircraft, as the initial aerodynamic angle of attack and elevator deflection of the simulation.

[0087] This step is mainly used to obtain the initial aerodynamic angle of attack and elevator deflection through 1g distribution, so as to carry out simulation cycle. In addition, refer to Figure 1 ,Before the simulation starts, it is also necessary to obtain ,parameters such as the aircraft speed, altitude, mass, and aerodynamic ,characteristics data set for use in simulation calculations.

[0088] In some optional implementations, step S1 further includes:

[0089] S11, obtaining input aircraft flight speed V, flight altitude H, aircraft mass m and aircraft aerodynamic characteristics data set;

[0090] S12, calculating the atmospheric density ρ at the flight altitude H, and further calculating the speed pressure Q of the aircraft;

[0091] S13, performing 1g trim on the aircraft based on the above parameters to obtain the trim angle of attack and the trim elevator deflection of the aircraft.

[0092] In some optional implementations, in step S12, the speed pressure Q of the aircraft is calculated by the following formula:

[0093] Q=0.5ρV.

[0094] In this embodiment, step S13 is a 1g trim step, which requires the use of the aircraft flight speed V, flight altitude H, aircraft mass m, aircraft aerodynamic characteristics data set and other parameters given in step S11, and also requires the use of the parameter speed pressure Q of step S12, which in turn needs to be calculated based on the atmospheric density ρ at the flight altitude H. In addition, in step S12, the speed of sound V at the flight altitude H also needs to be determined. S , in order to calculate the Mach number Ma for a given aircraft flight speed V.

[0095] After the calculation in step S13, the aircraft trim angle of attack α can be obtained. trim and trim elevator deflection δe trim , and use it as the aerodynamic angle of attack α and elevator deflection δe to participate in the subsequent simulation cycle.

[0096] Step S2: superimpose the aerodynamic coefficient increment caused by the downwash angle of attack onto the aerodynamic coefficient of the aircraft body to obtain an aerodynamic coefficient correction value, and determine the aerodynamic force of the aircraft according to the aerodynamic coefficient correction value.

[0097] With the aerodynamic angle of attack α and the elevator deflection δe, the aerodynamic force can be calculated.

[0098] In some optional implementations, step S2 further includes:

[0099] Step S21: interpolate the aerodynamic characteristic data set of the aircraft body to obtain the drag coefficient C of the aircraft under the current aerodynamic angle of attack and elevator deflection conditions. D , lift coefficient C L , pitch moment coefficient C my and pitch damping coefficient C mq ;

[0100] Step S22, interpolating the data set consisting of the aerodynamic characteristic data of the aircraft body and the downwash angle of attack to obtain the downwash aerodynamic coefficient increment;

[0101] Step S23: The drag coefficient C of the aircraft D , lift coefficient C L , pitch moment coefficient C my and pitch damping coefficient C mq Based on the aerodynamic coefficient increment, the aerodynamic drag D, lift L and pitch moment m of the aircraft are calculated. y .

[0102] In some optional embodiments, in step S21, the drag coefficient C of the aircraft is interpolated by the following formula: D , lift coefficient C L , pitch moment coefficient C my and pitch damping coefficient Cmq :

[0103]

[0104] Among them, the drag coefficient C of the aircraft is interpolated according to the flight Mach number Ma, the aerodynamic angle of attack α and the elevator deflection δe D , lift coefficient C L , pitch moment coefficient C my , according to the flight Mach number Ma, the aircraft trim angle of attack α interpolation pitch damping coefficient C mq .

[0105] In step S22, the downwash aerodynamic coefficient increment is obtained by interpolation through the following formula:

[0106]

[0107] Among them, according to the flight Mach number Ma, aerodynamic angle of attack α and downwash angle of attack Interpolating the drag coefficient of an aircraft Lift coefficient increment Pitch moment coefficient increment

[0108] In step S23, the aerodynamic drag D, lift L and pitch moment m of the aircraft are calculated according to the following formula: y :

[0109]

[0110] Among them, Q is the velocity pressure of the aircraft, S is the reference area of ​​the aircraft, q is the pitch angular velocity of the aircraft, V is the flight speed of the aircraft, and c is the average aerodynamic chord length.

[0111] In the above embodiment, it can be seen from the formula that based on the current flight Mach number Ma, aerodynamic angle of attack α, and elevator control deflection δe of the aircraft, the aerodynamic coefficient of the aircraft body can be interpolated. In step S22, the angle of attack and Mach number of the aircraft body are connected to jointly interpolate the downwash aerodynamic coefficient increment, including the drag coefficient increment Lift coefficient increment Pitch moment coefficient increment Among them, downwash angle of attack It is related to the flight state of the preceding aircraft that causes downwash. Finally, the aerodynamic force can be further obtained based on the aircraft parameters.

[0112] Step S3, solving the dynamic response of the aerodynamic force of the aircraft to obtain the flight speed, superimposing the flight speed with the wind speed of the vertical gust field to determine the corrected speed of the aircraft, and determining the aerodynamic angle of attack and the flight Mach number according to the corrected speed.

[0113] This step is mainly used to update the aerodynamic angle of attack so that step S2 can be used cyclically.

[0114] In some optional implementations, step S3 further includes:

[0115] Step S31, using the fourth-order Runge-Kutta method to solve the dynamic response of the aircraft, and obtain the projection value of the aircraft velocity on the X-axis and Z-axis of the body axis system, the pitch angle and the pitch angular velocity;

[0116] Step S32, superimposing the aircraft velocity with the wind speed of the vertical gust field to update the aircraft velocity component;

[0117] Step S33: determining a new aerodynamic angle of attack α and a flight Mach number Ma based on the updated velocity components of the aircraft.

[0118] In some optional implementations, in step S31, the dynamic response is solved by the following formula:

[0119]

[0120] Where m is the mass of the aircraft; g is the acceleration of gravity; u and w are the projection values ​​of the aircraft velocity on the X-axis and Z-axis of the body axis system respectively; θ is the pitch angle of the aircraft; I yy is the inertia moment of the aircraft relative to the Y axis of the body axis system;

[0121] F xf is the projection value of the aerodynamic force on the X-axis of the body axis system and the projection value of the engine thrust on the X-axis of the body axis system T The sum of zf is the projection value of the aerodynamic force on the Z axis of the body axis system and the projection value of the engine thrust on the Z axis of the body axis system T The sum of yf is the moment of aerodynamic force on the Y axis of the body axis system m y The moment m of the engine thrust on the Y axis of the body axis system T The calculation formula is as follows:

[0122]

[0123] In step S32, the velocity component of the aircraft is updated by the following formula:

[0124]

[0125] Among them, u g is the vertical gust field wind speed at the current moment;

[0126] In step S33, the new aerodynamic angle of attack α and the flight Mach number Ma are determined by the following formula:

[0127]

[0128] In step S31, the aerodynamic angle of attack α at the current simulation moment is used to solve the dynamic response. Then in step S32, the effect of the vertical gust field wind speed on the aircraft is considered to update the aircraft's velocity component. Finally, in step S33, the aerodynamic angle of attack α and the flight Mach number Ma are updated. The atan in the formula of step S33 is an inverse tangent function.

[0129] Step S4, according to the flight Mach number, pitch angular velocity, aerodynamic angle of attack, the wind speed of the given vertical gust field and the given elevator deflection, return to step S2, re-determine the aerodynamic force of the aircraft and loop the above steps until the simulation ends.

[0130] refer to Figure 1 At the new simulation moment, the downwash angle of attack, the pitch angular velocity q in step S31, the aerodynamic angle of attack α in step S33, the flight Mach number Ma, the given elevator deflection δe and the given wind speed in the vertical gust field are returned to step S2 to calculate the aerodynamic force of the aircraft at the current moment, and this cycle continues until the end of the simulation. Figure 2 A time history diagram of the wind speed of a given vertical gust field is given, with the horizontal axis being time and the vertical axis being wind speed.

[0131] The second aspect of the present application provides a flight simulation device under gust load considering downwash effect corresponding to the above method, mainly comprising:

[0132] The parameter initialization module is used to perform 1g level flight trim of the aircraft, determine the trim angle of attack of the aircraft and the trim elevator deflection of the aircraft, as the initial aerodynamic angle of attack and elevator deflection of the simulation;

[0133] an aerodynamic force calculation module, for superimposing the aerodynamic force coefficient increment caused by the downwash angle of attack onto the aerodynamic force coefficient of the aircraft body to obtain an aerodynamic force coefficient correction value, and determining the aerodynamic force of the aircraft according to the aerodynamic force coefficient correction value;

[0134] A dynamic response solving module is used to solve the dynamic response of the aerodynamic force of the aircraft, obtain the flight speed, determine the corrected speed of the aircraft after superimposing the flight speed on the wind speed of the vertical gust field, and determine the aerodynamic angle of attack and the flight Mach number according to the corrected speed;

[0135] The parameter updating module is used to redetermine the aerodynamic force of the aircraft according to the flight Mach number, the pitch angular velocity, the aerodynamic angle of attack, the wind speed of the given vertical gust field and the given elevator deflection.

[0136] In some optional implementations, the parameter initialization module includes:

[0137] A flight parameter acquisition unit, used to acquire input aircraft flight speed V, flight altitude H, aircraft mass m and aircraft aerodynamic characteristics data set;

[0138] The speed pressure calculation unit is used to calculate the atmospheric density ρ at the flight altitude H, and further calculate the speed pressure Q of the aircraft;

[0139] The trimming unit is used to perform 1g trim on the aircraft based on the above parameters to obtain the trim angle of attack and the trim elevator deflection of the aircraft.

[0140] In some optional implementations, in the speed-pressure calculation unit, the speed-pressure Q of the aircraft is calculated by the following formula:

[0141] Q=0.5ρV.

[0142] In some optional embodiments, the aerodynamic force calculation module includes:

[0143] The first interpolation unit is used to interpolate the aerodynamic characteristic data set of the aircraft body to obtain the drag coefficient C of the aircraft under the current aerodynamic angle of attack and elevator deflection conditions. D , lift coefficient C L , pitch moment coefficient C my and pitch damping coefficient C mq ;

[0144] A second interpolation unit is used to interpolate the aerodynamic characteristic data of the aircraft body and the downwash angle of attack to obtain the downwash aerodynamic coefficient increment;

[0145] Aerodynamic parameter calculation unit, used to calculate the drag coefficient C of the aircraft D , lift coefficient C L , pitch moment coefficient C my and pitch damping coefficient C mq Based on the aerodynamic coefficient increment, the aerodynamic drag D, lift L and pitch moment m of the aircraft are calculated. y .

[0146] In some optional embodiments, in the first interpolation unit, the drag coefficient C of the aircraft is interpolated by the following formula: D , lift coefficient C L , pitch moment coefficient C my and pitch damping coefficient C mq :

[0147]

[0148] Among them, the drag coefficient C of the aircraft is interpolated according to the flight Mach number Ma, the aerodynamic angle of attack α and the elevator deflection δe D , lift coefficient C L, pitch moment coefficient C my , according to the flight Mach number Ma, the aircraft trim angle of attack α interpolation pitch damping coefficient C mq ;

[0149] In the second interpolation unit, the downwash aerodynamic coefficient increment is obtained by interpolation using the following formula:

[0150]

[0151] Among them, according to the flight Mach number Ma, aerodynamic angle of attack α and downwash angle of attack Interpolate the drag coefficient increment of the aircraft Lift coefficient increment Pitch moment coefficient increment

[0152] In the aerodynamic parameter calculation unit, the aerodynamic drag D, lift L and pitch moment m of the aircraft are calculated according to the following formula: y :

[0153]

[0154] Among them, Q is the velocity pressure of the aircraft, S is the reference area of ​​the aircraft, q is the pitch angular velocity of the aircraft, V is the flight speed of the aircraft, and c is the average aerodynamic chord length.

[0155] In some optional implementations, the dynamic response solving module includes:

[0156] The dynamic response solving unit is used to solve the dynamic response of the aircraft by using the fourth-order Runge-Kutta method to obtain the projection value of the aircraft velocity on the X-axis and Z-axis of the body axis system, the pitch angle and the pitch angle velocity;

[0157] A velocity updating unit, used to superimpose the aircraft velocity on the wind speed of the vertical gust field to update the aircraft velocity component;

[0158] The longitudinal maneuvering load calculation unit is used to determine the new aerodynamic angle of attack α and the flight Mach number Ma based on the updated aircraft velocity components.

[0159] In some optional implementations, in the dynamic response solving unit, the dynamic response is solved by the following formula:

[0160]

[0161] Where m is the mass of the aircraft; g is the acceleration of gravity; u and w are the projection values ​​of the aircraft velocity on the X-axis and Z-axis of the body axis system respectively; θ is the pitch angle of the aircraft; I yy is the inertia moment of the aircraft relative to the Y axis of the body axis system;

[0162] Fxf is the projection value of the aerodynamic force on the X-axis of the body axis system and the projection value of the engine thrust on the X-axis of the body axis system T The sum of zf is the projection value of the aerodynamic force on the Z axis of the body axis system and the projection value of the engine thrust on the Z axis of the body axis system T The sum of yf is the moment of aerodynamic force on the Y axis of the body axis system m y The moment m of the engine thrust on the Y axis of the body axis system T The calculation formula is as follows:

[0163]

[0164] In the velocity update unit, the velocity component of the aircraft is updated by the following formula:

[0165]

[0166] Among them, u g is the vertical gust field wind speed at the current moment;

[0167] In the longitudinal maneuvering load calculation unit, the new aerodynamic angle of attack α and the flight Mach number Ma are determined by the following formula:

[0168]

[0169] A third aspect of the present application provides a computer device, which includes a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the flight simulation method under gust loads taking into account downwash as described above.

[0170] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A flight simulation method under gust load considering downwash effect, characterized in that: include: Step S1, performing level flight trim of the aircraft 1g, determining the trim angle of attack of the aircraft and the trim elevator deflection of the aircraft, which are used as the initial aerodynamic angle of attack and elevator deflection of the simulation; Step S2, adding the aerodynamic coefficient increment caused by the downwash angle of attack to the aerodynamic coefficient of the aircraft body to obtain an aerodynamic coefficient correction value, and determining the aerodynamic force of the aircraft according to the aerodynamic coefficient correction value; Step S3, solving the dynamic response of the aerodynamic force of the aircraft to obtain the flight speed, superimposing the flight speed with the wind speed of the vertical gust field to determine the corrected speed of the aircraft, and determining the aerodynamic angle of attack and the flight Mach number according to the corrected speed; Step S4, according to the flight Mach number, pitch angular velocity, aerodynamic angle of attack, the wind speed of the given vertical gust field and the given elevator deflection, return to step S2, re-determine the aerodynamic force of the aircraft and loop the above steps until the simulation ends.

2. The flight simulation method under gust load considering downwash effect as claimed in claim 1, characterized in that: Step S1 further comprises: S11, obtaining input aircraft flight speed V, flight altitude H, aircraft mass m and aircraft aerodynamic characteristics data set; S12, calculating the atmospheric density ρ at the flight altitude H, and further calculating the velocity pressure Q of the aircraft; S13. Perform 1g trim on the aircraft based on the above parameters to obtain the trim angle of attack and the trim elevator deflection of the aircraft.

3. The flight simulation method under gust load considering downwash effect as claimed in claim 2, characterized in that: In step S12, the speed pressure Q of the aircraft is calculated by the following formula: Q=0.5ρV.

4. The flight simulation method under gust load considering downwash effect as claimed in claim 1, characterized in that: Step S2 further comprises: Step S21: interpolate the aerodynamic characteristic data set of the aircraft body to obtain the drag coefficient C of the aircraft under the current aerodynamic angle of attack and elevator deflection conditions. D , lift coefficient C L , pitch moment coefficient C my and pitch damping coefficient C mq ; Step S22, interpolating the data set consisting of the aerodynamic characteristic data of the aircraft body and the downwash angle of attack to obtain the downwash aerodynamic coefficient increment; Step S23: The drag coefficient C of the aircraft D , lift coefficient C L , pitch moment coefficient C my and pitch damping coefficient C mq Based on the aerodynamic coefficient increment, the aerodynamic drag D, lift L and pitch moment m of the aircraft are calculated. y .

5. The flight simulation method under gust load considering downwash effect as claimed in claim 4, characterized in that: In step S21, the drag coefficient C of the aircraft is interpolated by the following formula: D , lift coefficient C L , pitch moment coefficient C my and pitch damping coefficient C mq : Among them, the drag coefficient C of the aircraft is interpolated according to the flight Mach number Ma, the aerodynamic angle of attack α and the elevator deflection δe D , lift coefficient C L , pitch moment coefficient C my , according to the flight Mach number Ma, the aircraft trim angle of attack α interpolation pitch damping coefficient C mq ; In step S22, the downwash aerodynamic coefficient increment is obtained by interpolation through the following formula: Among them, according to the flight Mach number Ma, aerodynamic angle of attack α and downwash angle of attack Interpolate the drag coefficient increment of the aircraft Lift coefficient increment Pitch moment coefficient increment In step S23, the aerodynamic drag D, lift L and pitch moment m of the aircraft are calculated according to the following formula: y : Among them, Q is the velocity pressure of the aircraft, S is the reference area of ​​the aircraft, q is the pitch angular velocity of the aircraft, V is the flight speed of the aircraft, and c is the average aerodynamic chord length.

6. The flight simulation method under gust load considering downwash effect as claimed in claim 1, characterized in that: Step S3 further comprises: Step S31, using the fourth-order Runge-Kutta method to solve the dynamic response of the aircraft, and obtain the projection value of the aircraft velocity on the X-axis and Z-axis of the body axis system, the pitch angle and the pitch angular velocity; Step S32, superimposing the aircraft velocity with the wind speed of the vertical gust field to update the aircraft velocity component; Step S33: determining a new aerodynamic angle of attack α and a flight Mach number Ma based on the updated velocity components of the aircraft.

7. The flight simulation method under gust load considering downwash effect as claimed in claim 6, characterized in that: In step S31, the dynamic response is solved by the following formula: Where m is the mass of the aircraft; g is the acceleration of gravity; u and w are the projection values ​​of the aircraft velocity on the X-axis and Z-axis of the body axis system respectively; θ is the pitch angle of the aircraft; I yy is the inertia moment of the aircraft relative to the Y axis of the body axis system; F xf is the projection value of the aerodynamic force on the X-axis of the body axis system and the projection value of the engine thrust on the X-axis of the body axis system T The sum of zf is the projection value of the aerodynamic force on the Z axis of the body axis system and the projection value of the engine thrust on the Z axis of the body axis system T The sum of yf is the moment of aerodynamic force on the Y axis of the body axis system m y The moment m of the engine thrust on the Y axis of the body axis system T The calculation formula is as follows: In step S32, the velocity component of the aircraft is updated by the following formula: Among them, u g is the vertical gust field wind speed at the current moment; In step S33, the new aerodynamic angle of attack α and the flight Mach number Ma are determined by the following formula:

8. A flight simulation device under gust loads taking into account downwash, characterized in that: include: The parameter initialization module is used to perform 1g level flight trim of the aircraft, determine the trim angle of attack of the aircraft and the trim elevator deflection of the aircraft, as the initial aerodynamic angle of attack and elevator deflection of the simulation; an aerodynamic force calculation module, for superimposing the aerodynamic force coefficient increment caused by the downwash angle of attack onto the aerodynamic force coefficient of the aircraft body to obtain an aerodynamic force coefficient correction value, and determining the aerodynamic force of the aircraft according to the aerodynamic force coefficient correction value; A dynamic response solving module is used to solve the dynamic response of the aerodynamic force of the aircraft, obtain the flight speed, determine the corrected speed of the aircraft after superimposing the flight speed with the wind speed of the vertical gust field, and determine the aerodynamic angle of attack and the flight Mach number according to the corrected speed; The parameter updating module is used to redetermine the aerodynamic force of the aircraft according to the flight Mach number, the pitch angular velocity, the aerodynamic angle of attack, the wind speed of the given vertical gust field and the given elevator deflection.

9. The flight simulation device under gust load considering downwash effect as claimed in claim 8, characterized in that: The parameter initialization module includes: A flight parameter acquisition unit, used to acquire input aircraft flight speed V, flight altitude H, aircraft mass m and aircraft aerodynamic characteristics data set; The speed pressure calculation unit is used to calculate the atmospheric density ρ at the flight altitude H, and further calculate the speed pressure Q of the aircraft; The trimming unit is used to perform 1g trim on the aircraft based on the above parameters to obtain the trim angle of attack and the trim elevator deflection of the aircraft.

10. The flight simulation device under gust load considering downwash effect as claimed in claim 9, characterized in that: In the speed-pressure calculation unit, the speed-pressure Q of the aircraft is calculated by the following formula: Q=0.5ρV.

11. The flight simulation device under gust load considering downwash effect as claimed in claim 8, characterized in that: The aerodynamic force calculation module comprises: The first interpolation unit is used to interpolate the aerodynamic characteristic data set of the aircraft body to obtain the drag coefficient C of the aircraft under the current aerodynamic angle of attack and elevator deflection conditions. D , lift coefficient C L , pitch moment coefficient C my and pitch damping coefficient C mq ; A second interpolation unit is used to interpolate the aerodynamic characteristic data of the aircraft body and the downwash angle of attack to obtain the downwash aerodynamic coefficient increment; Aerodynamic parameter calculation unit, used to calculate the drag coefficient C of the aircraft D , lift coefficient C L , pitch moment coefficient C my and pitch damping coefficient C mq Based on the aerodynamic coefficient increment, the aerodynamic drag D, lift L and pitch moment m of the aircraft are calculated. y .

12. The flight simulation device under gust load considering downwash effect as claimed in claim 11, characterized in that: In the first interpolation unit, the drag coefficient C of the aircraft is interpolated by the following formula: D , lift coefficient C L , pitch moment coefficient C my and pitch damping coefficient C mq : Among them, the drag coefficient C of the aircraft is interpolated according to the flight Mach number Ma, the aerodynamic angle of attack α and the elevator deflection δe D , lift coefficient C L , pitch moment coefficient C my , according to the flight Mach number Ma, the aircraft trim angle of attack α interpolation pitch damping coefficient C mq ; In the second interpolation unit, the downwash aerodynamic coefficient increment is obtained by interpolation using the following formula: Among them, according to the flight Mach number Ma, aerodynamic angle of attack α and downwash angle of attack Interpolate the drag coefficient increment of the aircraft Lift coefficient increment Pitch moment coefficient increment In the aerodynamic parameter calculation unit, the aerodynamic drag D, lift L and pitch moment m of the aircraft are calculated according to the following formula: y : Among them, Q is the velocity pressure of the aircraft, S is the reference area of ​​the aircraft, q is the pitch angular velocity of the aircraft, V is the flight speed of the aircraft, and c is the average aerodynamic chord length.

13. The flight simulation device under gust load considering downwash effect as claimed in claim 8, characterized in that: The dynamic response solving module comprises: The dynamic response solving unit is used to solve the dynamic response of the aircraft by using the fourth-order Runge-Kutta method to obtain the projection value of the aircraft velocity on the X-axis and Z-axis of the body axis system, the pitch angle and the pitch angle velocity; A velocity updating unit, used to superimpose the aircraft velocity on the wind speed of the vertical gust field to update the aircraft velocity component; The longitudinal maneuvering load calculation unit is used to determine the new aerodynamic angle of attack α and the flight Mach number Ma based on the updated aircraft velocity components.

14. The flight simulation device under gust load considering downwash effect as claimed in claim 13, characterized in that: In the dynamic response solving unit, the dynamic response is solved by the following formula: Where m is the mass of the aircraft; g is the acceleration of gravity; u and w are the projection values ​​of the aircraft velocity on the X-axis and Z-axis of the body axis system respectively; θ is the pitch angle of the aircraft; I yy is the inertia moment of the aircraft relative to the Y axis of the body axis system; F xf is the projection value of the aerodynamic force on the X-axis of the body axis system and the projection value of the engine thrust on the X-axis of the body axis system T The sum of zf is the projection value of the aerodynamic force on the Z axis of the body axis system and the projection value of the engine thrust on the Z axis of the body axis system T The sum of yf is the moment of aerodynamic force on the Y axis of the body axis system m y The moment m of the engine thrust on the Y axis of the body axis system T The calculation formula is as follows: In the velocity update unit, the velocity component of the aircraft is updated by the following formula: Among them, u g is the vertical gust field wind speed at the current moment; In the longitudinal maneuvering load calculation unit, the new aerodynamic angle of attack α and the flight Mach number Ma are determined by the following formula:

15. A computer device, characterized in that: The invention comprises a processor, a memory and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the flight simulation method under gust load considering downwash effect as described in any one of claims 1 to 7.

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