Ae odynamics Design and CFD Simula ion o a
Compac Ca Using OpenFOAM: A Case S udy om
Buca amanga, Colombia
ADRIAN VARGAS-LIZARAZO1,3, JORGE LUIS CHACÓN-VELASCO2,3
1Uni e sidad Indus ial de San ande , Mechanical Enginee ing school, osca 2191106@co eo.uis.edu.co
2Uni e sidad Indus ial de San ande , Mechanical Enginee ing school, [email p o ec ed]
3G upo de In es igación en Ene gía y Medio Ambien e – GIEMA, Buca amanga, Colombia
In oduc ion
Global e o s o mi iga e clima e change, ein o ced by
he Pa is Ag eemen , has p omp ed coun ies such as
Colombia o pu sue subs an ial educ ions in g eenhouse
gas (GHG) emissions. The anspo a ion sec o is one
o he main con ibu o s o hese emissions [1], pa icu-
la ly in u ban en i onmen s such as Buca amanga, which
is cha ac e ized by a wa m clima e and high-densi y mo-
bili y, whe e he ansi ion owa d elec ic and hyb id e-
hicles is i al. Howe e , in such ehicles, ae odynamic
d ag can cons i u e o e 50% o o al ene gy consump-
ion a c uising speeds [2], unde sco ing he necessi y o
enhance hei ae odynamic beha io o imp o e hei e -
iciency. This s udy p esen s he ae odynamic design and
and planned simula ion o a wo-passenge compac ehi-
cle using OpenFOAM as he main CFD ool. The wo k low
in ol es he use o CAD modeling and meshing s a e-
gies, wi h an ini ial baseline al eady p epa ed. The nex
s ages will inco po a e RANS-based simula ions wi h he
k–w SST model and la e ex end o a RANS–LES hyb id
app oach o cap u e wake u bulence. These simula ions
a e expec ed o be execu ed on high-pe o mance compu -
ing (HPC) esou ces o handle la ge meshes and educe
u na ound imes.
Go e ning Equa ions &
Tu bulence Modeling
To simula e he ai low a ound he ehicle, he mo ion
o he luid is go e ned by he Na ie –S okes equa ions
o incomp essible low. These include he conse a ion o
mass (con inui y) and momen um, which desc ibe how e-
loci y, p essu e, and iscosi y in e ac . In u bulen lows,
addi ional e ms a ise ha mus be modeled using u bu-
lence closu es. In his s udy, he k–w SST model will be
used o esol e bounda y laye s accu a ely.
Incomp esible RANS Equa ions
•Con inui y: Ensu es mass conse a ion in he low.
∇ · (¯
u) = 0(1)
•Momen um: Balances ine ia, p essu e, and
iscous o ces.
∂¯
u
∂ +∇ · (¯
u
¯
u)=−1
ρ(∇p)+ν∇2¯
u+1
ρ∇ · τR(2)
•Tu bulence model: k–ωSST, sol es wo
addi ional equa ions o modeling he u bulence,
namely, he u bulen kine ic ene gy and he speci ic
a e o dissipa ion.
∇ k+∇ · (¯
uk) = τR:∇¯
u
−β∗kω +∇ ·
ν+ν
σk
∇k
(3)
∂ω
∂ +∇ · (uω) = α
ν
τR:∇¯
u−βω2
+∇ ·
ν+ν
σω
∇ω
+2(1−F1)σω2
ω∇k· ∇ω
(4)
Kolmogo o scales
Figu e 1: Kolmogo o ’s Scales o u bulence.
Me hodology
The ae odynamic analysis o he compac ehicle is s uc-
u ed in h ee main phases. A he cu en s age, he
concep ual design and he i s compu a ional mesh ha e
been comple ed. These esul s p o ide he ounda ion o
subsequen simula ions. The ollowing sec ions summa-
ize he p og ess achie ed and he planned s eps ha will
ex end he s udy.
Phase 1: CAD design o he ehicle and ini ial
s eady-s a e RANS (k-w SST, y+=1).
Du ing he p elimina y phase, he ehicle’s concep ual de-
sign was de eloped in CAD so wa e, wi h emphasis on
minimizing he on al a ea and achie ing smoo h geo-
me ic ansi ions sui able o u ban en i onmen s.
Figu e 2: CAD model o he compac elec ic o hyb id
ehicle.
A i s compu a ional mesh was gene a ed, including lo-
cal e inemen s a ound he ehicle body and in he wake
egion. The nea -wall esolu ion was ensu ed wi h y+ 1,
allowing di ec cap u e o he iscous sublaye wi hou
wall unc ions. These ac ions es ablish he baseline o
accu a e e alua ion o ae odynamic coe icien s in he up-
coming simula ions.
Phase 2: Pa ame ic s udy
The nex s age will explo e how ehicle speed (40–70
km/h), g ound clea ance (250–300 mm), and accesso y
angles a ec ae odynamic beha io . The s udy will ocus
on d ag and li coe icien s, as well as su ace p essu e
dis ibu ions, o iden i y oppo uni ies o design imp o e-
men s.
Phase 3: Hyb id RANS-LESS (DESS
Finally, a Delayed De ached Eddy Simula ion (DDES) ap-
p oach will be applied. This hyb id model combines RANS
nea walls wi h LES in sepa a ed egions, allowing he es-
olu ion o la ge u bulen s uc u es in he wake wi hou
equi ing imp ac ically ine meshes.
P elimina y Resul s
So a , he p ojec has p oduced he CAD design o he e-
hicle and a i s compu a ional mesh. The mesh includes
e inemen s a ound he body and in he wake, wi h nea -
wall esolu ion adjus ed o y+ = 1. These p elimina y
esul s con i m he easibili y o he modeling app oach
and es ablish he ounda ion o subsequen ae odynamic
analyses. The upcoming s ages will build upon his base-
line o deli e quan i a i e ae odynamic coe icien s and
low ield cha ac e iza ions.
Figu e 3: Bounda y laye mesh e inemen a ound he e-
hicle.
Fo he mesh gene a ion, a domain wi h mo e han 3.3
million cells and 10 million aces was c ea ed, ensu ing
local e inemen s a ound he body and wake and nea -
wall esolu ion wi h y+ = 1. Mesh quali y was e i ied
wi h accep able alues (Table 2), con i ming i s sui abili y
o CFD analyses. Tes uns using 28 p ocesso s equi ed
app oxima ely 20 minu es o ela i ely sho simula ions
(mesh gene a ion), highligh ing he compu a ional in en-
si y o he p oblem.
Table 1: Mesh S a is ics.
Table 2: Mesh Quali y Summa y.
Acknowledgmen s
The au ho s acknowledge he suppo om MinCiencias
(p ojec 82713) o unding, and he Uni e sidad Indus ial
de San ande , especially he SC3 Labo a o y, o p o iding
he compu a ional esou ces o he simula ions.
Re e ences
[1] J. Thema and M. C. R. Ga cia, La ansición ene gé ica en
Colombia.
[2] P. Gonzales, “La ae odinámica en los coches eléc icos,”
Hacke Ca . Accessed: Ap . 29, 2025. [Online]. A ailable:
h ps://hacke ca .com/
po -que-la-ae odinamica-es-cla e-pa a-el- u u o-del-coche-elec ico/
[3] M. Leschzine , S a is ical u bulence modelling o luid
dynamics, demys i ied: an in oduc o y ex o g adua e
enginee ing s uden s. London; Hackensack, NJ: Impe ial
College P ess, 2016.
CARLA 2025, Sep embe 22-26, Kings on, Jamaica
