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AbstractDrag and its coefficient can be calculated by means ofvirtual environmental simulation with the help of wind tunnel or through
computer software. The use of computer software makes it possible to be
in time and cost savings. Numerical methods for doing this can be the
fluid flow by a two dimensional or three-dimensional model of the vehicle
structure to be resolved. This paper has tried to use the ANSYS !" and
the e#uations governing fluid flow combined with standard model solved
by using the appropriate boundary conditions. The study results of the
aerodynamic analysis of the air flow$ pressure distribution and drag force
on the vehicle. !ew design modifications in the form of attachable
accessories have been suggested in order to reduce the drag coefficient.
These modifications have shown a drag reduction of %&.'() at a speed of
*+ km,h with the drag coefficient reduced to +.* from +.'$ therebyreducing the fuel consumption by about appro/imately %&.'()$ which
means$ there is a saving of '.%&0 of petrol for every full tank refill. These
observations are validated using wind tunnel testing on a %1'2 scaled
model using momentum deficit method.
3eywords: Automotive Aerodynamics4 Drag oefficient4 !uelonsumption4 Numerical Analysis4 Drag pressure4 5ind Tunnel
Techni#ues$ 6omentum Deficit 6ethod$ !orce 7alance 6ethod
INTRODUCTION
Tata Nano was envisioned in 2003 to become a peoplesca! t"at is a##odable b$ eve$bod$! mainl$ t"e cit$ dwelleso# India% &ince its deb't in 200(! t"e sales o# Tata Nano "ave)one down temendo'sl$% In t"e #ist *'ate o# 20+3! n'mbe
o# ve"icles sold in t"e mont"s o# ,an'a$! -eb'a$ and .ac"
wee +/0! +/0/ and +/01 'nits! espectivel$% "en it was
#ist conceived! a ta)et pice o# +00!000 'pees was
establis"ed b't it cept 'p to abo't +2!000 'pees in ve$
s"ot time d'e to a steep incease in pice o# aw mateials and
inp't costs% dded to t"is! t"e soain) #'el pices! its no
lon)e an easil$ a##odable ca% &t'dies "ave s"own t"at +/
pecenta)e o# t"e #'el in a ve"icle is 'sed to ovecome
mec"anical #iction in t"e en)ine! / pecenta)e o# t"e #'el is'sed to ovecome t"e ollin) esistance and da) is esponsible
#o t"e emainin) 0pecenta)e% ca wit" low da) #oce
enco'ntes lesse #iction t"an a ca wit" "i)"e da) #oce%
4ence! a smalle en)ine is e*'ied to dive s'c" a ca w"ic"
event'all$ lowes t"e #'el cons'mption% In t"is pape we
#oc'ssed on ed'cin) t"e oveall da) #oce on t"e ve"icle! and
5+ 6 sst% 7o#! Dept% o# eona'tical and 'tomobile 8n)) .ail:mani9andan%mmanipal%ed'!! 2!3! 6 &t'dents! .anipal Instit'te o#
Tec"nolo)$! .anipal Univesit$! ;anata9aect
ssociate! Indian Instit'te o# Tec"nolo)$! ?and"i Na)a! India%
t"eeb$ bin)in) down t"e #'el cons'mption! "ence ma9in)t"e Tata Nano a)ain a #avo'ite amon) t"e Indian masses%
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obtained #o eac" velocit$% T"eoetical val'es wee validated
b$ wind t'nnel test 'sin) pess'e tappin)s and pitot t'bes on
a +:+/ model o# t"e ve"icle%
ni9et ;'l9ani! & A &atis" and A &aavanan 829 nal$sed
t"e #low patten o# a convetible #o two desi)ns i%e% wit" oo#
closed and wit" oo# open% &edan models wee ceated 'sin)'todes9 Invento so#twae! mes" )eneation was done 'sin)
?ambit and #inall$ pocessed in -l'ent 'sin) 9
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I.7ROAI&TION
T"e vaio's desi)n modi#ications t"at wee anal$Fed ae as
below
i dam
n ai dam ed'ces t"e aiect'e dawn was t"at t"e ma>oit$ o#
t"e da) #oce on t"e ve"icle wo'ld be d'e to t"e wa9e e)ionbe"ind t"e ca and not mainl$ d'e to #ontal ai impact%
Rea spoile
Da) is ai p's"in) a)ainst t"e ve"icle as it moves% T"e #aste
t"e ve"icle moves! t"e moe da)! w"ic" e*'ies moe powe
and #'el to maintain t"e speed% spoiles p'pose is to
ed'ce da)% n$ added s'#ace in ai#low adds to t"e da)%4oweve! )ood spoile desi)ns can ed'ce t"e oveall da) o#
$o' ve"icle%
4ence! t"e p'pose o# an a'tomotive spoile is to dis'pt! o
spoil! t"e ai#low ove t"e ca to impove pe#omance% T"is
desi)n ed'ced t"e da) #oce to +%322N
Rea pot'sion
ea pot'sion was desi)ned as s"own in t"e #i)'e PQQQ
Rea sceen
T"e best desi)n modi#ication came in t"e #om o# a ea
sceen% T"e sceen was /mm in t"ic9ness and di##eent
distances #om t"e ca ea wee anal$Fed%
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T"e epected e##ect o# aeod$namic da) ed'cin) is ac"ieved
#o t"e sa9e o# vote t"at oi)inates between ve"icle models
ea wall and sceen t"e vote enables noectives and Investi)ationsX! w"ite pape!s'bmitted to NRC Decadal &'ve$ Inne 7lanets &'bpanel! ')'st20++%
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P ColoFFa! %,%! Wis"ips #o 7laneta$ 8ploation,N&KCR