CN105740542A - Method for analyzing parachute performance in stormy weather - Google Patents
Method for analyzing parachute performance in stormy weather Download PDFInfo
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- CN105740542A CN105740542A CN201610065068.7A CN201610065068A CN105740542A CN 105740542 A CN105740542 A CN 105740542A CN 201610065068 A CN201610065068 A CN 201610065068A CN 105740542 A CN105740542 A CN 105740542A
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- G06F30/36—Circuit design at the analogue level
- G06F30/367—Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods
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Abstract
The invention discloses a method for analyzing the parachute performance in a stormy weather. The method comprises the steps of firstly establishing a filled parachute grid; secondly establishing a single raindrop SPH (Smoothed Particle Hydrodynamics) model according to experimental observation data; thirdly establishing a raindrop field through an array according to the actually measured raindrop field concentration; fourthly establishing an air flow field grid; fifthly assembling the parachute grid, the air flow field grid and the raindrop field model, and setting a boundary and an initial condition; sixthly calculating the air flow field and the raindrop field by adopting an ALE (Abitrary Lagrangian-Eulerian) method and an SPH method respectively, and calculating air-canopy coupling and raindrop-canopy contact by adopting a penalty function based contact algorithm; and finally analyzing calculation results. According to the method, the parachute performance in the stormy weather can be analyzed.
Description
Technical field
The present invention relates to parachute method for analyzing performance under a kind of rainstorm weather, belong to aviation lifesaving's technical field.
Background technology
Parachute is important aviation lifesaving or aerodynamic decelerator equipment, and parachute design or research are mainly all with ideal climate bar
Part is as premise.But in Practical Project, parachute needs to work in the presence of a harsh environment unavoidably, such as air-dropped material in wartime or people
Member, and vile weather such as rainstorm weather will produce important impact to parachute service behaviour.Due to the restriction of research technique, cruelly
Under rainy day gas, parachute performance evaluation is always a difficult point.
And existing numerical method also is difficult to be analyzed, this is because air flow field and single raindrop (carefully seeing aspect) belong to Euler
The category described, and raindrop field (macroscopic aspect) belongs to the category of Lagrange description, existing numerical model is difficult to retouch simultaneously
State air flow field and raindrop field.
Currently, engineering uses more ALE (Arbitrary Eulerian-Lagrangian) method (be referred to: Cheng Han, remaining
Jasmine, Li Shengquan. Parachute During Opening Process numerical simulation based on ALE. Nanjing Aero-Space University's journal, 2012,44 (3):
290-293.) it is only capable of analyzing flow field parachute work process is affected.And SPH (Smoothed Particle Hydrodynamics)
Method has the unexistent advantage of conventional mesh method as a kind of non-mesh method, due to the self adaptation character of SPH approximation method,
The random institute that SPH formula construction is not distributed by particle is affected, and can simulate the flowing of liquid in raindrop in thin sight aspect, and grand
Sight aspect can show again the discreteness of raindrop field.
Summary of the invention
The technical problem to be solved is to provide parachute method for analyzing performance under a kind of rainstorm weather, uses SPH particle
Set up raindrop field, parachute surely drop during the employing ALE method that couples of air and canopy, i.e. use two kinds of models to simulate respectively
Different fluid, but either raindrop canopy contacts or the coupling of air canopy all uses Contact Algorithm based on penalty function to carry out
Calculating, solving existing method cannot simultaneously simulated air flow field and the problem of raindrop field.The present invention analyzes under rainstorm weather first
Parachute service behaviour, design and research for parachute provide a brand-new method, have practical engineering application very
Important reference significance.
The present invention solves above-mentioned technical problem by the following technical solutions:
The present invention provides parachute method for analyzing performance under a kind of rainstorm weather, and the method includes step in detail below:
Step one: use Explicit Dynamical, it is thus achieved that the parachute grid of its fully unfolded position；
Step 2: set up single spherical raindrop SPH particle model, wherein, a diameter of actual measurement raindrop average quality of spherical raindrop
Weighted average diameter；
Step 3: according to actual measurement raindrop concentration, by array approach, set up raindrop field model；
Step 4: use hexahedron finite element grid, set up air flow field grid；
Step 5: parachute grid, raindrop field and air flow field grid are assembled, wherein, raindrop field is positioned at umbrella top and just goes up
Side；Setting speed entrance boundary bottom air flow field, velocity amplitude is parachute steady reduction of speed degree, and air flow field top is set to pressure
Outlet border, remaining wall of air flow field is zero recoil fraction；Raindrop field applies relative velocity, relative velocity be raindrop
Whole stabilized speed and the difference of parachute steady reduction of speed degree；
Step 6: be respectively adopted ALE method and SPH method and air flow field and raindrop field are calculated, air-canopy coupling
Couple with raindrop-canopy and all use Contact Algorithm based on penalty function to calculate；
Step 7: parachute performance is analyzed according to the result of calculation of step 6.
As the further scheme of the present invention, parachute grid, raindrop field and air flow field grid are assembled by step 5,
Particularly as follows: raindrop field particle is the most interspersed with air flow field grid, parachute grid is the most interspersed with air flow field grid, raindrop
Field is positioned at directly over umbrella top.
As the further scheme of the present invention, step 2 sets up single spherical raindrop based on pre-treatment platform LS-PREPOST
SPH particle model.
As the further scheme of the present invention, step 4 sets up air flow field grid based on pre-processing software LS-PREPOST.
As the further scheme of the present invention, single spherical raindrop include 12 SPH particles.
The present invention uses above technical scheme compared with prior art, has following technical effect that the present invention passes through different model,
Simulate air flow field and raindrop field, it is possible to achieve parachute performance evaluation under heavy rain, provide reference for engineering design and research.
Accompanying drawing explanation
Fig. 1 is parachute grid.
Fig. 2 is single raindrop particle model.
Fig. 3 is raindrop field models.
Fig. 4 is air flow field grid.
Fig. 5 is parachute grid, raindrop field and air flow field grid assembling model.
Fig. 6 is that raindrop field is dropped in profile on canopy and dynamically changes, and wherein, profile when (a) is 1.227s dynamically changes, (b)
Profile when being 1.428s dynamically changes, and profile when (c) is 1.683s dynamically changes, and profile when (d) is 1.9s dynamically becomes
Change.
Fig. 7 is that raindrop field is dropped in flow field velocity on canopy and dynamically changes, and wherein, flow field velocity when (a) is 1.227s is dynamic
Change, flow field velocity when (b) is 1.428s dynamically changes, and flow field velocity when (c) is 1.683s dynamically changes, and (d) is
Flow field velocity during 1.9s dynamically changes.
Fig. 8 is that single raindrop are dropped on canopy and dynamically change.
Fig. 9 is to contrast with or without raindrop field Canopy payload.
Detailed description of the invention
Below in conjunction with the accompanying drawings technical scheme is described in further detail:
The present invention is to solve a parachute performance evaluation difficult problem under rainstorm weather, below by method disclosed by the invention to rainstorm weather
During certain flat circle umbrella lower surely drops, service behaviour is analyzed.
First, use display dynamic method obtain be full of after parachute FEM (finite element) model (refer to: Han CHENG, Li YU,
Wei RONG,et al.A Numerical Study of Parachute Inflation Based on a Mixed Method.
Aviation, 2012,16 (4): 115-123.), parachute grid is as shown in Figure 1.
Then, with on July 7th, 2009, the heavy rain of a certain period is surveyed as modeling object in Pukou, Nanjing.The rain of this heavy rain
Strong is 62.54mm/h, and raindrop average quality weighted average diameter is 2.34mm, and concentration is that every cube of 1669 raindrop (can be joined
Examine: the observation and analysis of Chen Lei .2009-2010 Jianghuai Meiyu cutting edge of a knife or a sword heavy rain characteristics of Raindrop Spectra, [master thesis]. Nanjing: Nanjing information
Engineering university, 2011.).According to above-mentioned measured value, set up single raindrop SPH particle model, based on pre-processing software
LS-PREPOST sets up the spherical raindrop model of single diameter 2.34mm, as in figure 2 it is shown, single raindrop are by 12 SPH
Particle forms.
After again, according to actual measurement unit volume raindrop concentration, by array approach, set up raindrop field model, as it is shown on figure 3, its
Middle raindrop field is 6.5m × 6.5m × 4.5m, and SPH population is 3964740.
Being equally based on pre-processing software LS-PREPOST and set up air flow field grid, as shown in Figure 4, wherein air flow field is 14m
The cube of × 14m × 14m, uses 442176 hexahedral mesh to divide.
Above-mentioned parachute FEM (finite element) model, raindrop field SPH particle model and air flow field FEM (finite element) model are assembled, wherein
Raindrop field particle is the most interspersed with air flow field grid, and parachute grid is the most interspersed with air flow field grid, and raindrop field is positioned at
2.5m directly over umbrella top, after assembling, each model relative position relation is as shown in Figure 5.
Conditions setting: according to parachute steady reduction of speed degree 6m/s, be set to speed entrance (6m/s) bottom setting air flow field,
Air flow field top is set to pressure export (1atm), and remaining wall all uses zero recoil fraction.
According to test observation, the final stabilized speed of raindrop of diameter 2.34mm is about 7.5m/s, therefore defines raindrop field
The speed of parachute is 2.5m/s relatively.
Owing to air flow field uses finite element grid, and raindrop field uses SPH particle, air flow field and the calculating of raindrop field not to do mutually
Disturb.Wherein, air flow field employing ALE method calculating (referring to: Cheng Han, Yu Li, Li Shengquan. parachute based on ALE fills
Gas process value emulates. Nanjing Aero-Space University's journal, and 2012,44 (3): 290-293.).SPH particle calculates and then uses core letter
Number approximate calculation (referring to: Lin Xiaodong, Lu Yiyu, soup amasss core etc. and abrasive water-jet based on SPH-FEM coupling algorithm breaks rock number
Value is simulated. vibrate and impact .2014,33 (18): 170-176.).Meanwhile, two kinds of models are all based on Lagrange description, and therefore two
Coupling between kind of fluid and canopy calculates and can be converted into contact based on penalty function and calculate, it is thus achieved that canopy structure and flow field dynamic
State changes, thus obtains the mechanical response of parachute under heavy rain environment.
Finally, the platform of Intel Xeon E5-1630 processor and 32G internal memory simulates this type umbrella under heavy rain environment
Working condition, simulated time 1.9s, and the time that calculates reaches about 124h.Result of calculation is analyzed.
Fig. 6 and Fig. 7 respectively raindrop field is dropped in profile and flow field velocity on canopy and dynamically changes, and can clearly find from figure
This method truly simulates the process that heavy rain is dropped on parachute.And Fig. 8 is the change procedure that single raindrop are dropped on canopy,
The process of more droplet it is broken into after truly reflecting raindrop drippage.It is apparent that canopy is moved by heavy rain from the contrast of Fig. 9
Carrying and produce impact, under heavy rain effect, the average dynamic load of parachute diminishes, and parachute falling speed will be caused to accelerate.
From the point of view of being embodied as effect, the present invention can analyze parachute performance under heavy rain, can be engineering design and research offer
Important reference frame.
The above, the only detailed description of the invention in the present invention, but protection scope of the present invention is not limited thereto, and any ripe
Know the people of this technology in the technical scope that disclosed herein, it will be appreciated that the conversion expected or replacement, all should contain in the present invention
Comprise within the scope of, therefore, protection scope of the present invention should be as the criterion with the protection domain of claims.
Claims (5)
1. parachute method for analyzing performance under a rainstorm weather, it is characterised in that the method includes step in detail below:
Step one: use Explicit Dynamical, it is thus achieved that the parachute grid of its fully unfolded position；
Step 2: set up single spherical raindrop SPH particle model, wherein, a diameter of actual measurement raindrop average quality of spherical raindrop
Weighted average diameter；
Step 3: according to actual measurement raindrop concentration, by array approach, set up raindrop field model；
Step 4: use hexahedron finite element grid, set up air flow field grid；
Step 5: parachute grid, raindrop field and air flow field grid are assembled, wherein, raindrop field is positioned at umbrella top and just goes up
Side；Setting speed entrance boundary bottom air flow field, velocity amplitude is parachute steady reduction of speed degree, and air flow field top is set to pressure
Outlet border, remaining wall of air flow field is zero recoil fraction；Raindrop field applies relative velocity, relative velocity be raindrop
Whole stabilized speed and the difference of parachute steady reduction of speed degree；
Step 6: be respectively adopted ALE method and SPH method and air flow field and raindrop field are calculated, air-canopy coupling
Couple with raindrop-canopy and all use Contact Algorithm based on penalty function to calculate；
Step 7: parachute performance is analyzed according to the result of calculation of step 6.
Parachute method for analyzing performance under a kind of rainstorm weather the most according to claim 1, it is characterised in that in step 5
Parachute grid, raindrop field and air flow field grid are assembled, particularly as follows: raindrop field particle is mutual with air flow field grid
Interting, parachute grid is the most interspersed with air flow field grid, and raindrop field is positioned at directly over umbrella top.
Parachute method for analyzing performance under a kind of rainstorm weather the most according to claim 1, it is characterised in that in step 2
Single spherical raindrop SPH particle model is set up based on pre-processing software LS-PREPOST.
Parachute method for analyzing performance under a kind of rainstorm weather the most according to claim 1, it is characterised in that in step 4
Air flow field grid is set up based on pre-processing software LS-PREPOST.
Parachute method for analyzing performance under a kind of rainstorm weather the most according to claim 3, it is characterised in that single spherical
Raindrop include 12 SPH particles.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107389261A (en) * | 2017-07-17 | 2017-11-24 | 中国民用航空飞行学院 | A kind of parachuting process raindrop load evaluation method outside the venue |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103559335A (en) * | 2013-10-16 | 2014-02-05 | 南京航空航天大学 | Parachuting simulation method based on fluid structure interaction |
| CN104504174A (en) * | 2014-11-28 | 2015-04-08 | 南京航空航天大学 | Self-adaptive mesh control method applicable to fluid-solid coupling numerical simulation in paradrop process |
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2016
- 2016-01-31 CN CN201610065068.7A patent/CN105740542B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103559335A (en) * | 2013-10-16 | 2014-02-05 | 南京航空航天大学 | Parachuting simulation method based on fluid structure interaction |
| CN104504174A (en) * | 2014-11-28 | 2015-04-08 | 南京航空航天大学 | Self-adaptive mesh control method applicable to fluid-solid coupling numerical simulation in paradrop process |
Non-Patent Citations (3)
| Title |
|---|
| 余莉 等: "降落伞充气过程的数值模拟", 《航空学报》 * |
| 林晓东 等: "基于SPH-FEM耦合算法的磨料水射流破岩数值模拟", 《振动与冲击》 * |
| 陈猛 等: "降落伞充气过程流固耦合方法的数值预测分析", 《南京航空航天大学学报》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107389261A (en) * | 2017-07-17 | 2017-11-24 | 中国民用航空飞行学院 | A kind of parachuting process raindrop load evaluation method outside the venue |
| CN107389261B (en) * | 2017-07-17 | 2019-10-29 | 中国民用航空飞行学院 | A kind of over-the-counter load evaluation method of parachuting process raindrop |
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