CN106874529A

CN106874529A - A kind of low design methods for merging collar vortex and Discrete Gust model

Info

Publication number: CN106874529A
Application number: CN201510918578.XA
Authority: CN
Inventors: 黄翔; 于超鹏; 钱君
Original assignee: Leihua Electronic Technology Research Institute Aviation Industry Corp of China
Current assignee: Leihua Electronic Technology Research Institute Aviation Industry Corp of China
Priority date: 2015-12-11
Filing date: 2015-12-11
Publication date: 2017-06-20

Abstract

The present invention relates to a kind of low design methods for merging collar vortex and Discrete Gust model, design including micro handling system model and Discrete Gust model, step one, with runway threshold as origin, enter the runway coordinate system that nearly direction is+XR axles under set up collar vortex；Step 2, takes and determines collar vortex center, collar vortex radius, and center vertical velocity, can obtain the changeless collar vortex model of collar vortex center intensity；Step 3, configuration mirroring collar vortex；Step 4, introduces Discrete Gust model；Step 5, the prominent Wind gradient of the prominent wind model described in regulating step four；Step 6, the center of the prominent wind model of regulation and the relative position at collar vortex center, thus it is possible to vary the not size of wind shear center intensity in the same time, can be used for simulating the size of whole wind shear wind field intensity.The present invention devises a kind of wind shear model for merging collar vortex and discrete wind model, and the collar vortex center wind speed size of the model can be changed over time and changed.

Description

A kind of low design methods for merging collar vortex and Discrete Gust model

Technical field

The present invention relates to method invention field, specifically a kind of Low level wind for merging collar vortex and Discrete Gust model Shear model is designed, a kind of low model of actual natural phenomena of fitting of invention design, can be applied In aircraft is to the dangerous passive perception of wind shear and evades the research of performance and tests.

Background technology

Wind shear is a kind of meteor, refers to the change in air between 2 points on wind speed and direction, size Can be represented divided by distance or time with point-to-point transmission wind speed difference, including horizontal vertical wind shear, horizontal wind Horizontal shear, vertical wind shear.Low refers to less than 600 meters of wind shear, is and strong convection The relevant meteor of weather, frontal weather, low torrent, geography, environmental factor, serious harm aircraft Landing process.Low due to occur suddenly, the time is short, yardstick is small, intensity is big, when quality and be used to Property all larger big-and-middle-sized disposable on when, often due to flying height is too low, lacking enough spaces is carried out It is motor-driven and accident occurs.In-flight require that aircrew can timely have found it and avoid as far as possible, to ensure to fly Row safety.

Be to wind shear Modeling Research aircraft safety drive research basis, be aircraft encounter wind shear judge with Escape is provided fundamental basis, significant to reducing the related accident of aircraft wind shear.

Pertinent literature《Large aircraft modeling, danger souding and control law research under low》Middle proposition Low model is set up based on collar vortex method, the method be Control in Wind Shear Field is considered as can not press, without it is viscous, The bit stream of irrotationality, the intensity at this method collar vortex center based on collar vortex is changeless.But consider Actual natural phenomena, the center intensity of wind shear be not it is unalterable, change that it can over time and Change, therefore the model has very big difference with the influence by the wind shear of real conditions, it is impossible to reflection true to nature is true Situation, and then be unable to Validity Test aircraft flight each stage to wind shear dangerous criminal and evade performance.

The content of the invention

The purpose of innovation and creation

Existed to the seriousness of each phase security performance impact of aircraft flight, and existing model based on wind shear Wretched insufficiency, the present invention propose fusion collar vortex and discrete wind model wind shear modelling.The design changes Become the defect that original model collar vortex center wind speed is fixed, closer to actual natural phenomena, can be by adjusting whirlpool The central speed of ring, the different wind shear model of flexible construction.

The present invention has with the security performance on aircraft flight each stage and threatens this factor of wind shear for influenceing to grind Study carefully object, for the major defect for having pointed out correlation model at present, propose improved fusion Discrete Gust and whirlpool Ring wind shear model, greatly improved the laminating degree of the wind shear in wind shear model and actual natural phenomena, For simulation carry out aircraft flight to wind shear dangerous criminal and evade performance test provide it is more authentic and valid Wind field.And wind shear model proposed by the present invention can change except the wind speed at collar vortex center with the change of time, Can also flexible modulation collar vortex center and Discrete Gust model center relative position, so as to change suffered by aircraft Influence by the wind shear.Compared to existing wind shear model, the authenticity and validity of this invention have greatly Amplitude improve, more tally with the actual situation, to improve aircraft flight security performance test result accuracy and Validity is significant.

Technical scheme

The purpose of the present invention is achieved through the following technical solutions：

A kind of wind shear model for merging collar vortex and discrete wind model, mainly include micro handling system model and from Dissipate prominent wind model.So-called Discrete Gust, refers to that the wind speed of all directions in air in the short time occurs acute variation Air-flow.Due to the unstability of air motion, wind speed changes with the time.In flight quality mirror In fixed, strength of aircraft calculating and Design of Flight Control, so-called discrete wind model is widely used.Wherein, Be considered as wind shear by micro handling system model can not press, the bit stream without viscous, irrotationality, not consider temperature change.

A kind of low design methods for merging collar vortex and Discrete Gust model, including it is micro- under hit sudden and violent The design of flow model and Discrete Gust model, specific design step is as follows：

Step one, with runway threshold as origin, enter the runway coordinate system that nearly direction is+XR axles under set up collar vortex； So-called collar vortex refers to be produced by down draft, opens and rolls to surrounding divergence close to after ground, on the ground side Form a collar vortex area；

If being above the ground located at O_p=(x_p,y_p,z_p)^T, collar vortex radius is the main collar vortex curvilinear equation of R

Streamline equation at the center of gravity of airplane is

Wherein, collar vortex intensity Γ is by vertical speed V in collar vortex center set in advance_wz0Determine with collar vortex radius R：

Γ=2RV_wz0

r_max、r_minIt is any point O in space_ATo the minimum and maximum distance of main collar vortex；F (k) is ellptic integral Function, wherein：

When 0≤k≤1, F (k) can be approximated to be：

Step 2, takes and determines collar vortex center, collar vortex radius, and center vertical velocity, in can obtaining collar vortex The changeless collar vortex model of heart intensity；

Step 3, configuration mirroring collar vortex；In order that wind vector meets ground boundary condition, i.e. Vz=0, with The main collar vortex center position configuration mirroring collar vortex symmetrical relative to ground；

Step 4, introduces Discrete Gust model；

The Discrete Gust model of all-wave length is

Half-wavelength Discrete Gust model is

Discrete wind is main by prominent wind yardstick d_mWith intensity v_wmIt is determined that；And the gradient of prominent wind is calculated by following formula,

Step 5, the prominent Wind gradient of the prominent wind model described in regulating step four, wind shear center wind speed is with the time Change, the time-varying characteristics for simulating wind shear；

Step 6, the center of the prominent wind model of regulation and the relative position at collar vortex center, thus it is possible to vary not in the same time The size of wind shear center intensity, can be used for simulating the size of whole wind shear wind field intensity.

The advantage of invention

The wind shear model of present invention design more tallies with the actual situation compared with existing model, therefore to aircraft The verification and testing of the security performance research of flight has more validity and authenticity, is that research aircraft is driven safely Sail there is provided solid theoretical foundation, aircraft encounter wind shear is judged and is escaped provides more accurate survey Test ring border, it is significant to reducing the related accident of aircraft wind shear.The present invention devises a kind of fusion The wind shear model of collar vortex and discrete wind model, the collar vortex center wind speed size of the model can change over time and Change, and prominent wind model center can adjust with collar vortex center relative position, thus change wind shear size and Intensity, so that the model more preferable closer to reality nature situation, to the security performance test of aircraft flight more Tool validity.

Brief description of the drawings

Fig. 1 is micro handling system modular concept figure under runway coordinate system；

Fig. 2 is wind vector transverse and longitudinal generalized section of the present invention.

Specific embodiment

Scheme proposed by the present invention programs checking under Matlab R2010a environment, merges collar vortex and discrete wind The wind shear model of model, mainly includes micro handling system model and Discrete Gust model.So-called Discrete Gust, It refer to the air-flow of the wind speed generation acute variation of all directions in air in the short time.Due to the shakiness of air motion Qualitative, wind speed changes with the time.Calculated and flight control in flight quality identification, strength of aircraft In system design, so-called discrete wind model is widely used.Wherein, micro handling system model regards wind shear For that can not press, the bit stream without viscous, irrotationality, do not consider temperature change.

Comprise the following steps that：

Streamline equation at the center of gravity of airplane is

Γ=2RV_wz0

When 0≤k≤1, F (k) can be approximated to be：

Step 3, as shown in figure 1, configuration mirroring collar vortex；In order that wind vector meets ground boundary condition, That is Vz=0, in the position configuration mirroring collar vortex symmetrical relative to ground with main collar vortex center；

Step 4, introduces Discrete Gust model；

The Discrete Gust model of all-wave length is

Half-wavelength Discrete Gust model is

Step 6, the center of the prominent wind model of regulation and the relative position at collar vortex center, thus it is possible to vary not in the same time The size of wind shear center intensity, can be used for simulating the size of whole wind shear wind field intensity, Fusion Model As shown in Figure 2.

Claims

1. a kind of low design methods for merging collar vortex and Discrete Gust model, including micro handling system model and from Dissipate the design of prominent wind model, it is characterised in that specific design step is as follows：

Step one, with runway threshold as origin, enter the runway coordinate system that nearly direction is+XR axles under set up collar vortex；

\{\begin{matrix} {(x - x_{p})}^{2} + {(y - y_{p})}^{2} = R^{2} \\ z = z_{p} \end{matrix}

Streamline equation at the center of gravity of airplane is

ψ_{p} = \frac{Γ}{2 π} (r_{m a x} + r_{\min}) F (k)

Γ=2RV_wz0

r_max、r_minIt is any point O in space_ATo the minimum and maximum distance of main collar vortex；F (k) is ellptic integral function, its In：

k = | \frac{r_{m a x} - r_{\min}}{r_{m a x} + r_{\min}} |

When 0≤k≤1, F (k) can be approximated to be：

F (k) \approx \frac{0.788 k^{2}}{0.25 + 0.75 \sqrt{1 - k^{2}}}

Step 2, takes and determines collar vortex center, collar vortex radius, and center vertical velocity, can obtain collar vortex center intensity and fix not The collar vortex model of change；

Step 3, configuration mirroring collar vortex；In order that wind vector meets ground boundary condition, i.e. Vz=0, with main collar vortex center phase The position configuration mirroring collar vortex symmetrical for ground；

Step 4, introduces Discrete Gust model；

The Discrete Gust model of all-wave length is

v_{w} = \{\begin{matrix} 0 & x < 0 \\ \frac{v_{w m}}{2} (1 - \cos \frac{π x}{d_{m}}) & 0 \leq x \leq 2 d_{m} \\ 0 & x &GreaterEqual; 2 d_{m} \end{matrix}

Half-wavelength Discrete Gust model is

v_{w} = \{\begin{matrix} 0 & x < 0 \\ \frac{v_{w m}}{2} (1 - \cos \frac{π x}{d_{m}}) & 0 \leq x \leq 2 d_{m} \\ v_{w m} & x &GreaterEqual; d_{m} \end{matrix}

\frac{\partial v_{w}}{\partial x} = \frac{π}{2} \frac{v_{w m}}{d_{m}} s i n \frac{π x}{d_{m}}

Step 5, the prominent Wind gradient of the prominent wind model described in regulating step four, wind shear center wind speed is changed over time, for mould Intend the time-varying characteristics of wind shear；

Step 6, the center of the prominent wind model of regulation and the relative position at collar vortex center, thus it is possible to vary wind shear center is not strong in the same time The size of degree, can be used for simulating the size of whole wind shear wind field intensity.