7/23/2019 Effects of Cab to Trailer body roof height

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VEHICLE BODY

ENGINEERINGSeminar on

‘Effects of cab to trailer body roofheight’ 

 Prakash E (2012602035)

 Muzzammil Sheriff M (2012602036) Madras Institute of Tehnolo!"

 #nna $ni%ersit"& 'hennai

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7/23/2019 Effects of Cab to Trailer body roof height

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The most important factor which

contributes to ehic!e"s #ra$ resistance is

the e%pose# area of the trai!er bo#& aboethe cab roof re!atie to the cab"s fronta!

area' This is a!so (nown as roof hei$ht

step'

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Inesti$ation into the forebo#& #ra$ of

a truc( in a win#tunne! is ma#e where the

trai!er hei$ht is arie# re!atie to a fi%e#

cab hei$ht'

The #ra$ coefficient for #ifferent trai!er

 bo#& to cab hei$ht ratios )t* is p!otte#

as shown in +i$' ,'

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7/23/2019 Effects of Cab to Trailer body roof height

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+or this particu!ar cab to trai!er combination

#imensions there is no noticeab!e chan$e in

the #ra$ coefficient ' of -'./ with anincrease in trai!er bo#& to cab hei$ht ratio

unti! about ,'01 after which the #ra$

coefficient commence# to rise in proportionto the increase in the trai!er bo#& to cab

hei$ht ratio up to a t ratio of ,'21 which is

e3uia!ent to the ma%imum bo#& hei$ht of4'0 m5 which correspon#s to ma%imum #ra$

coefficient of -'6.'

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7/23/2019 Effects of Cab to Trailer body roof height

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Hence increasin$ the trai!er bo#& step

hei$ht ratio from ,'0 to ,'2 increases the

step hei$ht from -'2. m to ,'4 m an# inturn raises the #ra$ coefficient from -'./

to -'6.'

The rise in #ra$ coefficient of -'0/ is

consi#erab!e an# therefore stream!inin$

the air f!ow between the cab an# trai!er

 bo#& roof is of $reat importance'

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RE+ERENCE

  ,' 7#ance Vehic!e techno!o$& b& Hein8

Heis!er'

0' +rei$ht best practices b& 7ECO9 Lt#'

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