Initial Version of Missile-SIM for Performance evaluation

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litzj

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Unread post07 Sep 2018, 13:29

https://jaesan-aero.blogspot.com/2018/0 ... m-for.html

I want to get some feed back or useful information related to my simulation

Recently, I have worked some Python code for Missile-Rocket-Projectile Simulation having 2DOF.

Because I could only simulate lift/drag characteristics of the missile body as shown in Fig. 5, my simulation is relatively simple. Full 6DOF simulation work have been developed for Matlab code when the full 6DOF data, inertia, center of gravity, moment coefficient, is available, however, in most cases, it is not available.

Most of my article in the past was relied on estimation of hunch or prediction from common sense, however, I realized better tool for estimation is required. Although, modification of past Matlab code is easier way, study of python code is also enjoyable.

As a future plan, I perform CFD for supersonic reference cases via ANSA + StarCCM while improvement for this code will be done. below CFD figure is example.

After completion, analysis for Missile/SCRAMJET/Cruise Missile is on plan

1. Implemented
- Atmospheric / Gravity condition change via Altitude
- Calculation of Altitude, Speed, Range from Input Trajectory
- Consideration of multi-pulse or stage rocket
- Usage of Aerodynamic data for Mach/AoA

2. Planned or WIP
- Range optimization for missile? - recommendation of paper/report
- 3DoF/6DoF expansion - not planned (precise data for Inertia, CG is not available)
- Good reference case for certain missile shape - recommendation of paper/report
Attachments
Fig1.JPG
code sample
Fig2.JPG
Input trajectory
Fig3.JPG
Output sample
Fig4.jpg
Fig5.jpg
Fig6.jpg
Fig7.jpg
Fig8.jpg
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sprstdlyscottsmn

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Unread post07 Sep 2018, 14:04

As some who has a 6DOF simulation for missiles based on hunches and guessing, I appreciate the challenge.
"Spurts"

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litzj

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Unread post22 Sep 2018, 07:33

sprstdlyscottsmn wrote:As some who has a 6DOF simulation for missiles based on hunches and guessing, I appreciate the challenge.


Simulation itself can be configured for 6DOF, but achieving precise coefficient is too hard for 6DOF
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litzj

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Unread post22 Sep 2018, 07:34

https://jaesan-aero.blogspot.com/2018/0 ... e-sim.html

Recent update : validation for CFD setting for generic missile shape.

Unfortunately, I cannot achieve very precise aerodynamic coefficient due to limitation of CFD computing source

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litzj

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Unread post13 Oct 2018, 10:39

Full detail of the Article is here.

https://jaesan-aero.blogspot.com/2018/1 ... art-1.html

As the first study object, AIM-120C is chosen, and the objective of the study is sensitivity analysis for range performance and its optimization. Range of study includes "Rocket parameter", "Launch condition", and "Multi-stage version of CUDA".

This Part 1 will show sensitivity analysis of rocket parameter for AIM-120C baseline missile; Part 2 is optimization of rocket parameters and launch condition for longer range; Part 3 is proposal of AIM-120 sized dual-stage CUDA missile with optimized configuration.

Part 1 : Sensitivity Analysis of AIM-120C

As shown in Fig. 1-1, baseline of AIM-120C is modeled; some part of the data like propellant weight, and burn time are referenced from previous estimation work. Target parameters of the sensitivity are propellant weight, burn-time, ISP, Drag(CD), Lift(CL), and usage of dual-pulse.

Reference launch condition is set as M1.3 at 30000ft, and I assumed missile go straight without altitude change. Range is calculated when speed of the missile is re-decreased as M1.3 (The missile should pursue target having at least M1.3 speed).

As a summary of Sensitivity (M1.3, 30kft)

(1) 1.2 km Range↑, M 0.1 Speed↑ via 1.0 kg↑of Propellant (in given total weight)

(2) 0.67 km Range↑, almost zero Speed change via 1.0 s↑of Burn time (smaller mass-flow)

(3) 0.2 km Range↑, M 0.01 Speed↑ via 1.0 s↑of ISP

(4) 0.65 km Range↑, almost zero Speed change via 1.0 % Drag reduction

(5) almost zero Range, almost zero Speed change via 1.0 % Lift↑(negligible)

(6) 0.4 km Range↑, M 0.02 Speed↓ via 1.0 s increase of Dual pulse interval


Change of Lift is almost negligible for both range and peak speed performance. Higher lift configuration having more, longer, or larger fins is related to maneuverability and stability.
It is natural that increase of some parameters (Propellant, and ISP) are directly proportional to the range and speed increase.

Longer Burn-time and Drag reduction can increase range without change of speed performance.
(Tendency can be changed at different reference condition)

It could be interesting result that increase of Pulse interval can extend range while small decrease of peak speed.

In given hardware specification (weight, propellant, ISP, lift, and drag), longer burn-time and pulse interval are recommended to extend the range of the AIM-120C class missile.

Improvement via optimization will be performed at Part 2; Result of this sensitivity is applied while study for trajectory and launch condition will be conducted

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litzj

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Unread post21 Oct 2018, 08:48

I just published update of AIM-120C study using Missile-SIM

https://jaesan-aero.blogspot.com/2018/1 ... art-2.html

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marsavian

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Unread post21 Oct 2018, 09:44

A major part of the AIM-120D range increase is a climb trajectory similar to that used by the AIM-54. F-22 /Typhoon also like to fire AMRAAMs from high altitude (e.g. 45 to 65 kft) to get them to go further although 160km from 50 kft does sound a bit high from your model for the AIM-120C. There was a DCS validation study done on the C-5 and this model gets 38km range from low altitude where you get 24km and you get 65km at 30kft whereas it gets that range at 10km(32.8kft) altitude which implies your range correlation to altitude is too steep. The AIM-120C-5 does not just only do 24 km range at low altitude and as much as 160km range at high altitude and Mach (more like 90-100km) so somewhere you are not calculating right.

https://www.google.com/url?sa=t&source= ... KYZY4IS11U
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litzj

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Unread post07 Nov 2018, 12:21

marsavian wrote:A major part of the AIM-120D range increase is a climb trajectory similar to that used by the AIM-54. F-22 /Typhoon also like to fire AMRAAMs from high altitude (e.g. 45 to 65 kft) to get them to go further although 160km from 50 kft does sound a bit high from your model for the AIM-120C. There was a DCS validation study done on the C-5 and this model gets 38km range from low altitude where you get 24km and you get 65km at 30kft whereas it gets that range at 10km(32.8kft) altitude which implies your range correlation to altitude is too steep. The AIM-120C-5 does not just only do 24 km range at low altitude and as much as 160km range at high altitude and Mach (more like 90-100km) so somewhere you are not calculating right.

https://www.google.com/url?sa=t&source= ... KYZY4IS11U


You are very sharp; I found there was error related to altitude unit change (from feet to meter)

I will fix the result
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marsavian

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Unread post08 Nov 2018, 19:57

Cool, it's an interesting and relevant topic.
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litzj

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Unread post09 Nov 2018, 13:44

https://jaesan-aero.blogspot.com/2018/1 ... dance.html

Now, I added guidance part for this simulation (Also plot during calculation)

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ps. Also for fix of altitude bug : https://jaesan-aero.blogspot.com/2018/1 ... art-2.html
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sprstdlyscottsmn

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Unread post09 Nov 2018, 14:17

Fantastic work!
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