Sizing and Sensitivity Analysis of Aerobot for Planetary Exploration.doc

8/12/2019 Sizing and Sensitivity Analysis of Aerobot for Planetary Exploration.doc

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AbstractAerobot provides an aerial platform to collect in-situ data.Such a platform combines long-range mobility with opportunity to take

in situ and high spatial resolution remote sensing measurements on

regional to global scales. Russians VEGAS mission demonstrated the

application of aerobot for planetary eploration. !umerical simulations

using "#$ are carried out for the fluid flow around the aerobot with the

atmospheric condition from the estimation of flyable region over Venus.

Aspect ratios of the aerobot are ranged over % to & which are obtained

from the si'ing calculation through the iteration process. "ommercially

available package #luent was used to analy'e the flow around the body

and compute the drag components that are generated at different

velocities. #rom the numerical simulations and sensitivity analyses( it was

found that the drag components and balloon internal temperature are

strongly governed by the aspect ratio as well as the Reynolds number.

)he simulation results are presented in terms of skin friction drag co-

efficient( pressure drag co-efficient and total drag co-efficient variationsin terms of aspect ratio as well as Reynolds number. Sensitivity ofAerobot internal temperatures are carried out with different aspect ratios

and surface coatings by balancing the inflow and outflow of the radiant

energy.

*eywords: Aerobot( Venus( VEGA( +)A ,+ighter-)han-Airlatform

INTRODUCTION

Lighter-Than-Air (LTA) platform is sometimes knon asAero!ot" Aero!ot is one of the !est platforms for e#plorationon planets an$ moons ith an atmosphere% like &en's% ars%

or at'rn*s moon Titan" In +,. the o/iet la'n0he$ to pro!es

&ega + an$ &ega 1 into the atmosphere of &en's an$$emonstrate$ the feasi!ilit2 of the aero!ot for &en's

e#ploration3 Infa0t% in 'sing the aero!ot for planetar2

e#ploration% one of the most $iffi0'lt tasks is to insert them

into operation an$ 0ontrol it" Aero!ot enters the &en'sian

atmosphere ith the help of an 4aeroshell4% a heat shiel$ in the

shape of a flattene$ 0one" After atmospheri0 entr2% a para0h'te

ill e#tra0t the !alloon assem!l2 from the aeroshell% hi0h

falls aa2" The !alloon assem!l2 then $eplo2s an$ inflates"

5alloons ha/e !een long re0ogni6e$ as 'ni7'e% lo-0ost

s0ientifi0 platforms $'e to their relati/el2 lo 0ost an$ lo

poer 0ons'mption" In$ee$% the s'00essf'l &enera-&ega

8ro9e0t $emonstrate$ te0hni0al feasi!ilit2 of $eplo2ing a

+ ; Asst" 8rof% Dept" of Aerona'ti0al an$ A'tomo!ile


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The e#ploration of &en's near the s'rfa0e an$ the top of the

atmosphere ma2 pro/i$e the a$$itional information a!o't the

origin an$ e/ol'tion of &en's an$ it is also ne0essar2 to

'n$erstan$ the $2nami0al% 0hemi0al an$ geologi0 pro0ess on

other planets"

Tho'gh the &en's an$


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CONCLUION

Comp'tation of $rag for0e o/er the s'rfa0e of the en/elope at

$ifferent /elo0ities as ell as aspe0t ratios an$ the fl'i$ floaro'n$ en/elope 'sing n'meri0al sim'lation are 0arrie$ o't"

Jrom the n'meri0al sim'lations% it as o!ser/e$ that the skin-

fri0tion $rag% press're $rag an$ total $rag 0o-effi0ient are

strongl2 go/erne$ !2 the aspe0t ratio as ell as Re2nol$s

n'm!er"

R

Sizing and Sensitivity Analysis of Aerobot for Planetary Exploration.doc

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