CN103245485A - Judging device of sudden change character of ventilated supercavity balance point and judging method of sudden change character of ventilated supercavity balance point - Google Patents

Abstract

The invention belongs to the field of nonlinear dynamics and sensor detection, in particular relates to a judging device for determining the sudden change character of a ventilated supercavity balance point based on the theory of the nonlinear dynamics and a specified judging method of the sudden change character of the ventilated supercavity balance point. The judging device comprises an integral operation module, a perturbation analysis module, a sensor module, a data collection module, a data processing module and a comparison operation module. The judging device can judge the state of the ventilated supercavity more timely as per the navigation state of a navigation body during the navigation process of a ventilated supercavity navigation body, monitors the sensitive parameters which possibly cause sudden change and instability of ventilated supercavity in real time, and once the sensitive parameters of the ventilated supercavity are close to the sudden change critical parameter values, corresponding measures are taken, so that the sensitive parameters of the ventilated supercavity are far away from the sudden change critical parameter values, the stability of the ventilated supercavity is further ensured, and basic guarantee is provided for stable navigation of the ventilated supercavity navigation body.

Description

A kind of ventilation supercavity equilibrium point catastrophe characteristics decision maker and decision method thereof

Technical field

The invention belongs to nonlinear kinetics and sensor detection range, be specifically related to a kind of decision maker and special-purpose decision method thereof of the definite supercavity equilibrium point catastrophe characteristics based on nonlinear dynamics theory.

Background technology

The supercavity The Application of Technology can make under water or the frictional resistance of water surface movable body significantly reduces, improve headway, yet supercavitating flow is a kind of very complicated flow field problem, the flow phenomenon that has comprised more complicated in the fluid dynamics researchs such as non-permanent, compressible, phase transformation, turbulence has brought difficulty for the research of cavity dynamics.

Mainly adopt numerical simulation and two kinds of methods of experimental study at complicated cavity flow The Characteristic Study at present, research contents mainly concentrates in the analytical calculation and verification experimental verification of the numerical simulation of permanent ventilation supercavity form and the rule of ventilating.Wherein method for numerical simulation mainly adopts the flow field characteristic of the Boundary Element Method two and three dimensions supercavity in homogeneous equiulbrium flow theory and the potential flow theories, the new method of the flow-disturbing problem of burbling cavitation and calculating cavity form etc., as non-patent literature " numerical simulation study of a ventilation supercavity morphological stability " literary composition, be published in " Computational Mechanics journal ", develop a kind of computing method for the non-permanent ventilation supercavity form of calculating according to Logvinovich cavity cross section independently-inflatable principle in the literary composition, and used this method that ventilation supercavity morphological stability has been carried out numerical simulation study.Studies show that: model velocity, the elasticity of gases, ventilation rate, the rate of losing heart, body and cavitation device resistance coefficient all can exert an influence to ventilation supercavity morphological stability behind fluid field pressure, the model.Dissimilar disturbances with different modes are different to the influence of ventilation cavity morphological stability, and the ventilation supercavity shows property time lag and oscillating characteristic after receiving disturbance.This research method calculated amount is big, and execution cycle is long, needs the computing machine of high configuration that hardware condition is provided; And experimental study method such as non-patent literature " ventilation supercavity form and stability experiment research thereof ", be published in " Harbin Engineering University's journal ", by the serial experiment of in the water hole, carrying out ventilation supercavity form and stability thereof studied in the literary composition.Studies show that gravity is different to the formed ventilation supercavity influence of venting process and pass gas process, but ventilation supercavity axis variable increases with nonlinear way all.When gravity effect hour, under identical cavitation number, ventilation supercavity and natural supercavity are similar substantially on form and yardstick.The required preliminary work of experimental study is heavy, cost is high, repeatability is poor.

Summary of the invention

It is simple to the purpose of this invention is to provide a kind of process, simple operation, do not need to carry out the ventilation supercavity equilibrium point catastrophe characteristics decision maker of numerical simulation, the present invention also aims to provide a kind of ventilation supercavity equilibrium point catastrophe characteristics decision method of this device special use.

The object of the present invention is achieved like this:

Ventilation supercavity equilibrium point catastrophe characteristics decision maker, formed by integral operation module, perturbation analysis module, sensor assembly, data acquisition module, data processing module, comparison operation module, the integral operation module is carried out integral operation to existing cavity cross section expansion equation, and the integral operation result is inputed to the perturbation analysis module; The perturbation analysis module is carried out linearization process to ventilation cavity volume, the sensitive parameter collection of output ventilation supercavity equilibrium point sudden change; The sensitive parameter that sensor assembly is measured the ventilation cavity inputs to data acquisition module; Data acquisition module carries out the data that collect the A/D conversion and inputs to data processing module; Data processing module carries out filtering, storage and curve plotting to the sensitive parameter that obtains; The comparative analysis module compares with the actual measured value of data processing module the sensitive parameter collection of perturbation analysis module output, judges the undergo mutation possibility of characteristic of the supercavity equilibrium point of ventilating.

Sensor assembly comprises the pressure transducer of gaging pressure and measures the acceleration transducer of movable body acceleration; Data acquisition module adopts data collecting card, and data processing module adopts single-chip microcomputer, and the integral operation module adopts singlechip chip, perturbation analysis module to adopt singlechip chip, and the comparison operation module adopts the operational amplifier chip.

Sensitive parameter comprises pressure, the movable body acceleration.

Ventilation supercavity equilibrium point catastrophe characteristics decision method comprises the steps:

(1) set up cavity cross section expansion equation:

$\frac{{\∂}^{2}S(\mathrm{\τ},t)}{\∂t^2}=-\frac{k_1\mathrm{\Δp}(\mathrm{\τ},t)}{\mathrm{\ρ}},x\left(t\right)-l\left(t\right)\≤\mathrm{\ξ}\≤x\left(t\right),$

$S(\mathrm{\τ},\mathrm{\τ})=\frac{\mathrm{\π}{D}_n^2}{4},\frac{\∂S(\mathrm{\τ},\mathrm{\τ})}{\∂t}=\frac{k_{1}A}{4}{D}_{n}V\sqrt{c_x}$

Δ p in the formula (τ, t)=p _∞(ξ)+p ₁(t)-p _c(t), wherein τ≤t is the cross section ξ rise time; X (t) is the absolute x coordinate of cavity generator current time t correspondence; p ₁(t) be the environmental pressure disturbance; p _c(t) be the cavity internal pressure; p _∞(ξ) be the environmental pressure of infinite distant place; L (t) is cavity length; c _xBe the cavity drag coefficient; k ₁=4 π A ², A=2 is empirical constant, D _nBe the cavitation device diameter, V is real time kinematics body speed;

(2) existing cavity cross section expansion equation is carried out integral operation:

With initial cavity length l ₀With movable body speed V _∞As scale, cavity cross section expansion equation is carried out nondimensionalization handles:

$\frac{{\∂}^{2}S(\mathrm{\τ},t)}{\∂t^2}=-\frac{k_1\mathrm{\σ}\left(t\right)}{2},t-l\left(t\right)\≤\mathrm{\τ}\≤t$

Wherein σ (t) is cavitation number, and the closure condition of cavity is:

S(t,t)=S(t-l(t),t)→0

The cavity cross section of nondimensionalization expansion equation is carried out twice integration to be got:

$S(\mathrm{\τ},t)=\frac{k_1{\mathrm{\σ}}_0}{4}[t-\mathrm{\τ}-2\underset{\mathrm{\τ}}{\overset{t}{\∫}}(t-u)\stackrel{\‾}{\mathrm{\σ}}\left(u\right)\mathrm{du}]$

In the formula

σ ₀Be natural cavitation number, u is integration variable,

Obtain the integral equation of contact ventilation supercavity length and cavitation number in conjunction with the cavity closure condition:

$l\left(t\right)=2\underset{t-l\left(t\right)}{\overset{t}{\∫}}(t-u)\stackrel{\‾}{\mathrm{\σ}}\left(u\right)\mathrm{du};$

(3) calculate unique equilibrium point of ventilation supercavity, the cavity volume carried out linearization process at the equilibrium point place, obtain may the undergo mutation parameter area of characteristic of linear perturbation system and ventilation supercavity:

Cavity balanced gas quality dimensionless equation is:

$\frac{d}{\mathrm{dt}}\left[(\mathrm{\β}-\stackrel{\‾}{\mathrm{\σ}}\left(t\right))Q\left(t\right)\right]=\mathrm{\β}[{\stackrel{\·}{q}}_{\mathrm{in}}-{\stackrel{\·}{q}}_{\mathrm{out}}\left(t\right)]$

Wherein β is the dynamic similarity parameter,

Be Ventilation Rate,

Be time dependent disappointing speed, the integral equation associating with contacting ventilation supercavity length and cavitation number obtains the unique equilibrium point of ventilation supercavity:

$\stackrel{\‾}{\mathrm{\σ}}\left(t\right)=1,l\left(t\right)=1$

With the cavity volume $Q\left(t\right)=\frac{k_1{\mathrm{\σ}}_0}{4}[-\frac{l^2\left(t\right)}{2}+\underset{t-l\left(t\right)}{\overset{t}{\∫}}{(t-u)}^2\stackrel{\‾}{\mathrm{\σ}}\left(u\right)\mathrm{du}]$ Carry out linearization process at the equilibrium point place, obtain the linear perturbation system:

$\left\{\begin{array}{c}{\stackrel{\·}{\mathrm{\σ}}}_1\left(t\right)=a{\mathrm{\σ}}_1\left(t\right)+b\\ i_1\left(t\right)=\frac{a{\mathrm{\σ}}_1\left(t\right)+2\mathrm{b\ϵ}{l}_1\left(t\right){\mathrm{\σ}}_1\left(t\right)+b}{2\mathrm{\ϵ}{l}_1\left(t\right)-1}\end{array}\right.$

Wherein a and b are parametric variable, and ε is dimensionless, obtain Jacobi matrix and the eigenwert of linear perturbation, judge that may the undergo mutation parameter area of characteristic of ventilation supercavity is 2.6196＜β;

(4) sensitive parameter of measurement ventilation supercavity, sensitive parameter is carried out the calculating of filtering, numeric ratio, storage and curve plotting, the sensitive parameter of ventilation supercavity compares with sudden change critical parameters value, judges the ventilation supercavity during greater than sudden change critical parameters value when sensitive parameter and undergos mutation; Judging the ventilation supercavity during less than sudden change critical parameters value when sensitive parameter does not undergo mutation.

Beneficial effect of the present invention is: the present invention is in the process of supercavity sail body navigation, can be according to the residing state of the more timely judgement ventilation supercavity of the operational configuration of sail body, the supercavity unsettled sensitive parameter of undergoing mutation that may cause ventilating of monitoring in real time, in case the sensitive parameter of ventilation supercavity approaches sudden change critical parameters value, just take appropriate measures, make the sensitive parameter of ventilation supercavity away from sudden change critical parameters value, and then guarantee the stability of ventilation supercavity, for the steady steaming of supercavity sail body provides basic guarantee.

Description of drawings

Fig. 1 is for judging the device composition frame chart of ventilation supercavity equilibrium point catastrophe characteristics;

Fig. 2 is for judging the ventilate method of supercavity equilibrium point catastrophe characteristics and the workflow diagram of device.

Embodiment

Below in conjunction with accompanying drawing the present invention is described further:

Composition frame chart of the present invention is made up of integral operation module, perturbation analysis module, sensor assembly, data acquisition module, data processing module and comparative analysis module as shown in Figure 1.The function of wherein said integral operation module and perturbation analysis module is realized by mcu programming; The measurement of the pressure signal that sensor assembly is realized and the measurement function of acceleration signal are realized multimetering by miniature patch formula pressure transducer respectively, and obtaining by the single-axis accelerometer ADXL190 with simulating signal output of movable body linear acceleration measured; The function that data acquisition module is realized is realized collection and the digital conversion of simulating signal by the A/D function of pci data capture card; The integral operation function that data processing module is finished and multiplication and division are calculated and are realized by mcu programming; The comparison operation module is finished by mcu programming equally, and the programmable I of single-chip microcomputer/O pin receives the output of perturbation analysis module and data processing module.A kind of workflow diagram of device embodiment of definite ventilation supercavity equilibrium point catastrophe characteristics as shown in Figure 2.

The present invention includes integral operation module, perturbation analysis module.The integral operation module is based on the approximate mathematical model of Logvinovich cavity cross section expansion independence principle, obtain cavity cross section expansion equation, closure condition according to the cavity afterbody, cavity cross section expansion equation is carried out Integral Processing, obtain the integral equation of contact ventilation supercavity length and cavitation number; The perturbation analysis module is carried out linearization process with the cavity volume at the equilibrium point place, obtains the linear perturbation system, and may the undergo mutation parameter area of characteristic of ventilation supercavity.Concrete steps are as follows:

(a) employing obtains cavity cross section expansion equation based on the approximate mathematical model of Logvinovich cavity cross section expansion independence principle

$\frac{{\∂}^{2}S(\mathrm{\τ},t)}{\∂t^2}=-\frac{k_1\mathrm{\Δp}(\mathrm{\τ},t)}{\mathrm{\ρ}},x\left(t\right)-l\left(t\right)\≤\mathrm{\ξ}\≤x\left(t\right),---\left(1\right)$

$S(\mathrm{\τ},\mathrm{\τ})=\frac{\mathrm{\π}{D}_n^2}{4},\frac{\∂S(\mathrm{\τ},\mathrm{\τ})}{\∂t}=\frac{k_{1}A}{4}{D}_{n}V\sqrt{c_x}$

Δ p in the formula (τ, t)=p _∞(ξ)+p ₁(t)-p _c(t), wherein τ≤t is the cross section ξ rise time; X (t) is the absolute x coordinate of cavity generator current time t correspondence; p ₁(t) be the environmental pressure disturbance; p _c(t) be the cavity internal pressure; p _∞(ξ) be the environmental pressure of infinite distant place; L (t) is cavity length; c _xBe the cavity drag coefficient; k ₁=4 π A ², A=2 is empirical constant, D _nBe the cavitation device diameter, V is real time kinematics body speed.

With initial cavity length l ₀With movable body speed V _∞As scale, equation (1) is carried out nondimensionalization handle,

$\frac{{\∂}^{2}S(\mathrm{\τ},t)}{\∂t^2}=-\frac{k_1\mathrm{\σ}\left(t\right)}{2},t-l\left(t\right)\≤\mathrm{\τ}\≤t---\left(2\right)$

Wherein σ (t) is cavitation number, and the closure condition of cavity is

S(t,t)=S(t-l(t),t)→0(3)

In conjunction with closure condition (3), equation (2) is carried out integration twice, draw

$S(\mathrm{\τ},t)=\frac{k_1{\mathrm{\σ}}_0}{4}[t-\mathrm{\τ}-2\underset{\mathrm{\τ}}{\overset{t}{\∫}}(t-u)\stackrel{\‾}{\mathrm{\σ}}\left(u\right)\mathrm{du}]---\left(4\right)$

In the formula

σ ₀Be natural cavitation number, u is integration variable.With (4) formula substitution cavity closure condition (3), draw the contact unknown function

And the equation of l (t)

$l\left(t\right)=2\underset{t-l\left(t\right)}{\overset{t}{\∫}}(t-u)\stackrel{\‾}{\mathrm{\σ}}\left(u\right)\mathrm{du}---\left(5\right)$

(b) result with the integral operation module combines with cavity balanced gas quality dimensionless equation, calculates unique equilibrium point of ventilation supercavity.

Cavity balanced gas quality dimensionless equation is

$\frac{d}{\mathrm{dt}}\left[(\mathrm{\β}-\stackrel{\‾}{\mathrm{\σ}}\left(t\right))Q\left(t\right)\right]=\mathrm{\β}[{\stackrel{\·}{q}}_{\mathrm{in}}-{\stackrel{\·}{q}}_{\mathrm{out}}\left(t\right)]---\left(6\right)$

Wherein β is dynamic similarity parameter (equaling the ratio of steam cavitation number and its actual numerical value), plays an important role in calculating non-stationary cavity stream, and β=1 is equivalent to the nature supercavity.When β increased, the elasticity of gases in the ventilation supercavity increased.

Be Ventilation Rate,

Be time dependent disappointing speed.Equation (5) is united the unique equilibrium point of acquisition ventilation supercavity with equation (6) Utilize the perturbation analysis module with the cavity volume $Q\left(t\right)=\frac{k_1{\mathrm{\σ}}_0}{4}[-\frac{l^2\left(t\right)}{2}+\underset{t-l\left(t\right)}{\overset{t}{\∫}}{(t-u)}^2\stackrel{\‾}{\mathrm{\σ}}\left(u\right)\mathrm{du}]$ Carry out linearization process at the equilibrium point place, obtain the linear perturbation system, $\left\{\begin{array}{c}{\stackrel{\·}{\mathrm{\σ}}}_1\left(t\right)=a{\mathrm{\σ}}_1\left(t\right)+b\\ i_1\left(t\right)=\frac{a{\mathrm{\σ}}_1\left(t\right)+2\mathrm{b\ϵ}{l}_1\left(t\right){\mathrm{\σ}}_1\left(t\right)+b}{2\mathrm{\ϵ}{l}_1\left(t\right)-1}\end{array}\right.,$ Wherein a and b are parametric variable, and ε is dimensionless, obtain Jacobi matrix and the eigenwert of system, according to the bifurcated theory, judge that may the undergo mutation parameter area of characteristic of ventilation supercavity is 2.6196＜β.

The present invention also comprises sensor assembly, data acquisition module, data processing module, comparison operation module.Sensor assembly comprises pressure sensor module and acceleration sensor module, and pressure sensor module is made up of a plurality of pressure transducers, the voltage signal p that output is directly proportional with the cavity internal pressure _{C_a}, acceleration transducer is measured the movable body linear acceleration, and exports corresponding voltage signal a _aData acquisition module adopts the voltage signal p of the real-time pick-up transducers module output of the A/D function in the data collecting card _{C_a}And acceleration signal a _aAnd convert them to corresponding digital signal p _{C_d}And a _dData processing module is finished by mcu programming, carries out integration by the signal to acceleration transducer output and obtains rate signal

Utilize

Relation, p _∞Be environmental pressure, obtain actual cavitation number, and then obtain β; The comparison operation module is finished by mcu programming equally, and whether the β of comparing data processing module output drops in the parameter area that the perturbation analysis module obtains, to determine the ventilation supercavity phenomenon of whether can undergoing mutation.If β close to critical value, changes the numerical value of β with taking the necessary measures.

Claims (5)

1. ventilation supercavity equilibrium point catastrophe characteristics decision maker, formed by integral operation module, perturbation analysis module, sensor assembly, data acquisition module, data processing module, comparison operation module, it is characterized in that: the integral operation module is carried out integral operation to existing cavity cross section expansion equation, and the integral operation result is inputed to the perturbation analysis module; The perturbation analysis module is carried out linearization process to ventilation cavity volume, the sensitive parameter collection of output ventilation supercavity equilibrium point sudden change; The sensitive parameter that sensor assembly is measured the ventilation cavity inputs to data acquisition module; Data acquisition module carries out the data that collect the A/D conversion and inputs to data processing module; Data processing module carries out filtering, storage and curve plotting to the sensitive parameter that obtains; The comparative analysis module compares with the actual measured value of data processing module the sensitive parameter collection of perturbation analysis module output, judges the undergo mutation possibility of characteristic of the supercavity equilibrium point of ventilating.

2. a kind of ventilation supercavity equilibrium point catastrophe characteristics decision maker according to claim 1 is characterized in that: described sensor assembly comprises the pressure transducer of gaging pressure and measures the acceleration transducer of movable body acceleration; Data acquisition module adopts data collecting card, and data processing module adopts single-chip microcomputer, and the integral operation module adopts singlechip chip, perturbation analysis module to adopt singlechip chip, and the comparison operation module adopts the operational amplifier chip.

3. a kind of ventilation supercavity equilibrium point catastrophe characteristics decision maker according to claim 1, it is characterized in that: described sensitive parameter comprises pressure, the movable body acceleration.

4. a ventilation supercavity equilibrium point catastrophe characteristics decision method is characterized in that, comprises the steps:

(1) set up cavity cross section expansion equation:

$\frac{{\∂}^{2}S(\mathrm{\τ},t)}{\∂t^2}=-\frac{k_1\mathrm{\Δp}(\mathrm{\τ},t)}{\mathrm{\ρ}},x\left(t\right)-l\left(t\right)\≤\mathrm{\ξ}\≤x\left(t\right),$

$S(\mathrm{\τ},\mathrm{\τ})=\frac{\mathrm{\π}{D}_n^2}{4},\frac{\∂S(\mathrm{\τ},\mathrm{\τ})}{\∂t}=\frac{k_{1}A}{4}{D}_{n}V\sqrt{c_x}$

Δ p in the formula (τ, t)=p _∞(ξ)+p ₁(t)-p _c(t), wherein τ≤t is the cross section ξ rise time; X (t) is the absolute x coordinate of cavity generator current time t correspondence; p ₁(t) be the environmental pressure disturbance; p _c(t) be the cavity internal pressure; p _∞(ξ) be the environmental pressure of infinite distant place; L (t) is cavity length; c _xBe the cavity drag coefficient; k ₁=4 π A ², A=2 is empirical constant, D _nBe the cavitation device diameter, V is real time kinematics body speed;

(2) existing cavity cross section expansion equation is carried out integral operation:

With initial cavity length l ₀With movable body speed V _∞As scale, cavity cross section expansion equation is carried out nondimensionalization handles:

$\frac{{\∂}^{2}S(\mathrm{\τ},t)}{\∂t^2}=-\frac{k_1\mathrm{\σ}\left(t\right)}{2},t-l\left(t\right)\≤\mathrm{\τ}\≤t$

Wherein σ (t) is cavitation number, and the closure condition of cavity is:

S(t,t)=S(t-l(t),t)→0

The cavity cross section of nondimensionalization expansion equation is carried out twice integration to be got:

$S(\mathrm{\τ},t)=\frac{k_1{\mathrm{\σ}}_0}{4}[t-\mathrm{\τ}-2\underset{\mathrm{\τ}}{\overset{t}{\∫}}(t-u)\stackrel{\‾}{\mathrm{\σ}}\left(u\right)\mathrm{du}]$

In the formula σ ₀Be natural cavitation number, u is integration variable,

Obtain the integral equation of contact ventilation supercavity length and cavitation number in conjunction with the cavity closure condition:

$l\left(t\right)=2\underset{t-l\left(t\right)}{\overset{t}{\∫}}(t-u)\stackrel{\‾}{\mathrm{\σ}}\left(u\right)\mathrm{du};$

(3) calculate unique equilibrium point of ventilation supercavity, the cavity volume carried out linearization process at the equilibrium point place, obtain may the undergo mutation parameter area of characteristic of linear perturbation system and ventilation supercavity:

Cavity balanced gas quality dimensionless equation is:

$\frac{d}{\mathrm{dt}}\left[(\mathrm{\β}-\stackrel{\‾}{\mathrm{\σ}}\left(t\right))Q\left(t\right)\right]=\mathrm{\β}[{\stackrel{\·}{q}}_{\mathrm{in}}-{\stackrel{\·}{q}}_{\mathrm{out}}\left(t\right)]$

Wherein β is the dynamic similarity parameter,

Be Ventilation Rate,

Be time dependent disappointing speed, the integral equation associating with contacting ventilation supercavity length and cavitation number obtains the unique equilibrium point of ventilation supercavity:

$\stackrel{\‾}{\mathrm{\σ}}\left(t\right)=1,l\left(t\right)=1$

With the cavity volume $Q\left(t\right)=\frac{k_1{\mathrm{\σ}}_0}{4}[-\frac{l^2\left(t\right)}{2}+\underset{t-l\left(t\right)}{\overset{t}{\∫}}{(t-u)}^2\stackrel{\‾}{\mathrm{\σ}}\left(u\right)\mathrm{du}]$ Carry out linearization process at the equilibrium point place, obtain the linear perturbation system:

$\left\{\begin{array}{c}{\stackrel{\·}{\mathrm{\σ}}}_1\left(t\right)=a{\mathrm{\σ}}_1\left(t\right)+b\\ i_1\left(t\right)=\frac{a{\mathrm{\σ}}_1\left(t\right)+2\mathrm{b\ϵ}{l}_1\left(t\right){\mathrm{\σ}}_1\left(t\right)+b}{2\mathrm{\ϵ}{l}_1\left(t\right)-1}\end{array}\right.$

Wherein a and b are parametric variable, and ε is dimensionless, obtain Jacobi matrix and the eigenwert of linear perturbation, judge that may the undergo mutation parameter area of characteristic of ventilation supercavity is 2.6196＜β;

(4) sensitive parameter of measurement ventilation supercavity, sensitive parameter is carried out the calculating of filtering, numeric ratio, storage and curve plotting, the sensitive parameter of ventilation supercavity compares with sudden change critical parameters value, judges the ventilation supercavity during greater than sudden change critical parameters value when sensitive parameter and undergos mutation; Judging the ventilation supercavity during less than sudden change critical parameters value when sensitive parameter does not undergo mutation.

5. a kind of ventilation supercavity equilibrium point catastrophe characteristics decision method according to claim 4, it is characterized in that: described sensitive parameter comprises pressure, the movable body acceleration.

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