Internati
o
nal
Journal of P
o
wer Elect
roni
cs an
d
Drive
S
y
ste
m
(I
JPE
D
S)
V
o
l.
7, N
o
. 1
,
Mar
c
h
20
16
,
pp
. 23
5
~
24
5
I
S
SN
: 208
8-8
6
9
4
2
35
Jo
urn
a
l
h
o
me
pa
ge
: h
ttp
://iaesjo
u
r
na
l.com/
o
n
lin
e/ind
e
x.ph
p
/
IJPEDS
Augmen
ted Dif
f
user f
o
r Hori
zontal
Axi
s
M
a
rine Current
Turbine
A.H
.
A
.
Elb
a
tr
an
*,***
, O.B
.
Ya
ak
ob
**
, Yasser
M. Ahme
d
*,****
, Firdaus
B. Abdullah
*
*Faculty
of
Mechanical Engin
eer
ing, Univ
ersiti Teknologi Malay
s
ia, 81310, Skudai, Johor
, Malay
s
ia
**Marine
Techn
o
log
y
Cen
t
er
, U
n
iversiti Teknologi Malay
s
ia, 81
310, Skudai, Joh
o
r, Malay
s
ia
***Faculty
of Engineer
ing,
Ar
ab
Academ
y
for
Science
and
Techn
o
log
y
and
Maritime Transport, A
l
exandr
ia, Eg
y
p
t
****Dept. o
f
Naval Arch
itictur
e
and Marin
e
Engineering
,
Faculty
of Engin
eerin
g,
Alexandria Univ
ersity
, Alex
andria,
Eg
y
p
t
Article Info
A
B
STRAC
T
Article histo
r
y:
Received Nov 30, 2015
Rev
i
sed
Jan 23, 201
6
Accepted
Feb 12, 2016
The pot
ent
i
al
of
renewab
l
e
ener
g
y
s
ourc
e
s
is
en
orm
ous
as
the
y
can m
a
ke
a
major contr
i
bution to th
e futur
e
of energ
y
needs. The o
c
ean
has a gr
eat
potenti
al
to b
e
c
o
m
e
a pra
c
ti
ca
l
a
nd pred
ict
a
bl
e
energ
y
s
ourc
e
c
o
m
p
ared to
other en
erg
y
res
ources
s
u
ch as
s
o
lar,
wind,
and
nuclear. It off
e
rs different
sources of energy which can be
utili
zed nam
e
l
y
wave, tid
al, offs
hore wind,
thermal, and tid
a
lcurr
e
nt. Amon
g thes
e sources, marine tidal current has
m
a
jor advan
t
ag
e
s
such as high
er
power
av
ail
a
bi
l
i
t
y
and
pred
ict
a
bilit
y.
The
m
a
in objectiv
e of this research work
is to desig
n
and develop a horizontal
axis m
a
rine
cur
r
ent
turbine
(H
AMCT) that
suitabl
e for
oper
a
ting with
in
M
a
la
y
s
ian o
c
e
a
n
, which has
lo
w s
p
eed curren
t
(0.5 – 1 m
/
s
a
v
erage)
. A
prototy
p
e of au
gmented diffuser
4-bladed HAMCT apply
i
ng NACA 0014
was proposed in the current stud
y
.
The turbin
e model has 0.666 m diameter,
and it was designed to produce as mu
ch as power from flowing water
current. Model was constructed
and te
sted at
Marine Technolog
y
Center
(MTC) in thre
e
conditions
, nam
e
l
y
, fr
ee
tow tes
ting, du
cted
tow testing
,
and
ducted diffuser
tow testing in order to pr
edi
c
t the
power and effic
i
enc
y
of the
turbine s
y
s
t
em
.
The res
u
l
t
s
s
howed that
the
appli
cat
ion of
duct was
significant to
co
ncentr
ate the flow
and diffuser
arrang
ement w
a
s effectiv
e
when it was pl
ac
ed behind of
the
rotor in th
is con
d
ition of
low water curr
en
t
s
p
eed.
The
m
a
xi
m
u
m
efficien
c
y
Cp obta
i
ned
in
t
h
e curr
ent
s
y
s
t
e
m
was
0.58.
Keyword:
Au
gm
ent
e
d di
f
f
use
r
HAM
CT
Power
Power coe
ffici
ent
Copyright ©
201
6 Institut
e
o
f
Ad
vanced
Engin
eer
ing and S
c
i
e
nce.
All rights re
se
rve
d
.
Co
rresp
ond
i
ng
Autho
r
:
Al
y
Hassa
n
A
b
dal
l
a
El
bat
r
a
n
,
Depa
rtm
e
nt
of Aeronautics, Autom
o
tive
and Ocean
E
ngi
nee
r
ing
Faculty of Mec
h
anical E
n
gine
ering
Un
i
v
ersiti Tekn
o
l
o
g
i
Malaysia (UTM)
8
131
0 UTM, Sk
ud
ai
Jo
hor
Bah
r
u
,
Jo
hor
, Malaysia
H
/
p
:
0
060
197
04
095
2.
Em
a
il: Haaaly2@m
a
il.live.utm
.
my
1.
INTRODUCTION
Tid
a
l cu
rren
t
po
wer is on
e of th
e m
o
st i
m
p
o
r
tan
t
clean power res
o
urce in t
h
e worl
d espec
i
ally
micro
applications.
Major adva
ntages of this ene
r
gy are the
nat
u
re
of t
h
e c
u
r
r
e
nt
fl
o
w
, w
h
i
c
h can
be p
r
edi
c
t
e
d an
d
t
h
e gre
a
t
den
s
i
t
y
of wat
e
r
fl
ui
d [
1
]
.
M
o
re
o
v
e
r
, t
h
e
densi
t
y
o
f
ene
r
gy
p
r
od
u
ced by
wat
e
r fl
ow i
s
a
p
p
r
o
x
i
m
at
ely
a t
housa
n
d t
i
m
e
s
m
o
re t
h
an t
h
at
by
wi
n
d
en
ergy
. T
h
ere
f
o
r
e, t
i
d
al
curre
nt
energy
i
s
con
s
i
d
ere
d
t
o
be a hi
g
h
l
y
av
ailab
l
e en
erg
y
source and
as yet n
o
t
fu
ll
y u
tilized
.
W
a
t
e
r turb
i
n
es
u
s
ed
for tid
al curren
t g
e
n
e
ratio
ns were
ori
g
i
n
al
l
y
de
v
e
l
ope
d
fo
r
wi
nd
f
o
rce
ge
ne
rat
i
ons
[
2
]
.
T
h
e t
y
pes
o
f
e
m
pl
oy
ed t
i
d
al
cur
r
e
n
t
p
o
w
e
r
can
be
ch
aracterized
by th
eir ro
tatio
nal ax
is orien
t
at
io
n
with
resp
ect to
th
e
water
flo
w
d
i
rection
.
Hen
c
e, th
ere are two
Evaluation Warning : The document was created with Spire.PDF for Python.
I
S
SN
:
2
088
-86
94
I
J
PED
S
Vo
l. 7,
No
.
1,
Mar
c
h
2
016
: 2
3
5
–
24
5
23
6
m
a
i
n
t
echnol
o
g
i
e
s fo
r t
h
e en
ergy
ext
r
act
i
o
n
from
m
a
ri
ne cur
r
ent
s
. They
are h
o
ri
zo
nt
al
fl
o
w
t
u
r
b
i
n
es (
H
A
T
)
and c
r
oss fl
ow
t
u
r
b
i
n
es.
H
o
ri
zont
al
fl
ow t
u
rbi
n
es ha
ve a
x
es paral
l
e
l
t
o
t
h
e fl
ui
d.B
a
se
d
on t
h
e com
p
ari
s
o
n
bet
w
ee
n t
h
e t
h
ree m
e
t
hods, i
t
was
not
i
ced
t
h
at
H
A
M
C
T
of
fere
d t
h
e
hi
ghe
st
p
o
t
e
nt
i
a
l
i
n
ge
ne
rat
e
d
po
we
r
fr
om
water
cu
r
r
ent [3
, 4]
.
Malaysia is a
country that is
surrounde
d
by ocean, thus it need
s to devel
op the
tidal curre
nt
tech
no
log
y
fo
r d
e
v
e
lop
i
ng
the en
erg
y
sect
or [5
,
6
]
. Malaysia h
a
s m
a
in
prob
lem
s
wh
ich are low
v
e
lo
city o
f
cur
r
ent
a
nd l
o
w wat
e
r
de
pt
h
a
ppea
r
s. T
h
e
o
p
t
i
m
u
m
curre
n
t
speed for ide
a
l
m
a
rine turbi
n
e operati
on is
at leas
t
2
m
/
s [7
]. Ho
wev
e
r, th
e av
erag
ely cu
rren
t v
e
lo
city in
m
a
ny
l
o
cat
i
on i
n
M
a
l
a
y
s
i
a
i
s
onl
y
1
m
/
s [8]
.
M
o
re
ove
r,
o
p
e
n
t
u
rb
in
es
ex
tract en
erg
y
fro
m
th
e flu
i
d
b
y
redu
cing
t
h
e flow
v
e
locity with little o
r
no
p
r
essure
redu
ctio
n
as the fl
uid
pa
sses through t
h
e turbi
n
e
rot
o
r. T
h
e st
ream
l
i
n
es m
u
st th
erefore ex
p
a
nd
to m
a
in
tain
con
tin
u
ity
an
d
they can
not ex
p
a
n
d
ind
e
fin
itely [9
]. Hence th
ere is a th
eo
retical li
m
i
t
to
th
e p
e
rcen
tag
e
of k
i
n
e
tic en
erg
y
t
h
at
can
be
ext
r
act
ed
fr
om
t
h
e fl
ui
d.
Thi
s
l
i
m
i
t
has bee
n
s
h
o
w
n
by
B
e
t
z
t
o
be
5
9
.
3
%
[1
0]
f
o
r
a si
ngl
e
act
uat
o
r
di
sk
. A n
u
m
b
er of c
o
m
p
rom
i
ses and m
odi
fi
cat
i
ons are re
q
u
i
r
e
d
fo
r t
u
r
b
i
n
e desi
gn i
n
o
r
de
r t
o
excee
d
B
e
t
z
li
mit [1
1
]
. Hence, Kirk
e [9
] in
creased
th
e
po
wer co
efficien
t
m
o
re th
an
B
e
tz li
mit
b
y
u
tilizin
g
do
ub
le actu
a
to
r
d
i
sk wh
ich prov
ed th
at t
h
e correspo
n
d
i
ng
li
mit is 6
4
%
fo
r th
is case. Furth
e
rm
o
r
eVenn
e
ll [11
]
,
Venn
el
l [12
]
an
d Venn
ell [13
]
ex
ceed
e
d
the Betz li
m
i
t b
y
u
tilizin
g
farm
s of turb
i
n
es i
n
ch
ann
e
l
The si
m
p
l
e
st
m
e
t
hod t
o
en
h
a
ncet
he
HAM
C
T
effi
ci
ency
i
s
t
o
encl
o
s
e i
t
i
n
t
o
a
duct
o
r
nozzl
e.
Usi
n
g
duct
o
r
s
h
r
o
ud
ar
ou
n
d
t
u
r
b
i
n
e en
han
ces the flow
velocit
y
ar
oun
d th
e
ru
nn
er.
In th
is
case, th
e v
e
l
o
city is
higher com
p
ared t
o
a
fre
e rotor. T
h
is e
nha
ncem
ent
in
creases th
e to
tal
h
a
rn
essed
po
wer fro
m
tid
al Cu
rren
t
R
i
ver or o
p
en sea.
F
u
rt
herm
ore,
t
h
i
s
i
d
ea ha
s
bee
n
pr
op
ose
d
f
o
r
deca
des
i
n
t
h
e wi
n
d
t
u
r
b
i
n
e
t
e
c
h
n
o
l
o
g
i
es
bu
t
it is not successful c
o
mm
erci
ally [4], [14].
Scherillo
et al.,
[15] ac
hieve
d
7.5% inc
r
ease i
n
the HAT e
ffici
ency
base
d o
n
di
f
f
us
er exi
t
area. Th
ei
r st
udy
was c
a
rri
ed
out
by
n
u
m
e
ri
cal
and expe
ri
m
e
nt
al
i
nvest
i
g
at
i
o
ns. L
u
q
u
et
et al. [
1
6
]
op
timized
th
e d
e
sig
n
o
f
th
e
du
ct an
d
the r
o
t
o
r
of
cu
rr
en
t tu
rb
in
e to
enh
a
n
ce th
e f
l
ow
r
a
te th
rough
t
h
e t
u
r
b
i
n
e
by
usi
n
g t
h
e R
A
NS
num
eri
cal
m
e
t
hod;
t
h
ey
achi
e
ve
d a hi
g
h
er
p
o
we
r coe
ffi
ci
ent
o
f
0.
7
5
wi
t
h
o
p
tim
u
m
d
e
sign
o
f
th
e
du
ct an
d th
e
ro
to
r.
The press
u
re drop
available
to
a ducted t
u
rbine
de
pends on the s
h
ape of t
h
e duct
and t
h
e fl
ow
th
ro
ugh
an
d aro
und
it.
If th
e
d
u
c
t is d
e
sign
ed
as a
d
i
ffu
s
er it will draw
m
o
re flu
i
d thro
ugh
it an
d wi
ll also
increase t
h
e available press
u
re drop across t
h
e turbi
n
e
by
r
ecove
ri
n
g
s
o
m
e
of t
h
e vel
o
ci
t
y
head d
o
w
n
s
t
r
eam
as press
u
re
he
ad, t
h
e t
u
rbi
n
e
t
h
en bec
o
m
e
s
“di
f
f
u
se
r- a
u
g
m
ent
e
d”[
17]
.
C
onsi
d
era
b
l
e
wo
rk
has bee
n
do
ne o
n
d
i
f
f
u
s
er
-
a
ug
m
e
n
t
ed
w
i
nd
t
u
rbin
e d
e
sign
,
bu
t th
e co
ncep
t
has no
t so
far
been
system
atic
ally ap
p
lied
t
o
water
tu
rb
in
es. Howev
e
r th
e
d
i
ffuser co
n
c
ep
t
h
a
s lesser m
u
ch
pu
b
lish
e
d in
t
h
e literatu
re
fo
r
cu
rren
t
water t
u
rb
in
e.
Kirke [9] showed t
h
at the
theoretical m
a
xim
u
m powe
r
coefficient fo
r a
di
ff
use
r-a
u
g
m
e
nt
ed t
u
r
b
i
n
e
ba
sed o
n
tu
rb
in
e area is 1
.
9
6
tim
es h
i
g
h
e
r th
an
th
e Betz li
mit. Th
is
i
s
possi
bl
e
bec
a
use fl
o
w
i
s
dr
awn i
n
fr
om
a
great
e
r
area upstream
than that inte
r
cept
e
d
by
t
h
e
sam
e
si
zed t
u
r
b
i
n
e i
n
o
p
e
n
fl
ow
. O
n
t
h
e
ot
her
ha
nd
, Da
vi
d et
al
.
[18] proved
numerically that the di
ff
user
conf
igu
r
ation
pr
odu
ced
3
.
1
ti
m
e
s
m
o
re p
o
wer t
h
an
th
e t
u
rb
in
e with
no
di
f
f
u
ser
.
F
u
rt
herm
ore, B
u
y
u
n
g
et
al
. [
19]
a
n
d
C
h
e
n
et
al
. [1
7]
c
o
n
d
u
ct
ed e
x
pe
ri
m
e
nt
all
y
a test
on
h
o
rizon
t
al-ax
i
s wind
tu
rb
in
e with
an
d wi
t
h
o
u
t
a fl
an
ge
d di
f
f
u
ser
,
t
h
e
i
r results s
h
owed t
h
at the
flange
d
di
ff
use
r
ca
n si
gni
fi
cant
l
y
i
n
c
r
ease t
h
e
p
o
w
er
out
put
,
t
o
r
q
ue
out
put
,
an
d
r
o
t
o
r
r
o
t
a
t
i
o
n
a
l
spee
d
of t
h
e wi
n
d
t
u
r
b
i
n
e. P
o
nt
a [2
0]
rep
r
ese
n
t
e
d di
f
f
use
r-a
u
g
m
e
nt
ed fl
oat
i
ng
hy
d
r
o
-
t
u
rbi
n
es t
o
i
m
prov
e t
h
e t
echni
ca
l
an
d
econom
i
c perform
a
nce. Sha
h
savari
fard
et al.,
[
1
4]
desi
gn
ed a
n
d
t
e
st
ed
expe
ri
m
e
nt
al
ly i
n
t
h
e
wat
e
r t
u
n
n
el
facility at th
e
Un
i
v
ersity of Man
itob
a
a 1
9
.8 cm
d
i
a
m
eter HAT
with
two
sh
rou
d
s
. Th
e
p
e
ak
power
enha
ncem
ent
of 9
1
% o
v
er t
h
e
uns
hr
o
ude
d t
u
rbi
n
e was
obt
a
i
ned wi
t
h
t
h
e s
t
rai
ght
wal
l
di
f
f
use
r
. El
bat
r
an
et
al
.
[2
1]
de
pl
oy
e
d
di
ff
use
r
a
ugm
ent
e
d c
h
a
nnel
ar
ou
n
d
c
r
oss
fl
o
w
/
B
a
nki
t
u
r
b
i
n
es.
Th
is l
o
w curren
t
ch
aracteristi
c is th
e m
a
in
co
n
s
i
d
erat
i
o
n
o
f
t
h
e c
u
rre
nt
st
udy
.
He
nce
,
m
odi
fi
cat
i
ons
o
f
th
e ex
isting m
a
rin
e
cu
rrent tu
rb
in
es
are
neede
d
t
o
overcom
e
low c
u
rre
nt
s
p
eed
i
n
M
a
l
a
y
s
i
a
n oce
a
n
[6]
.
Thu
s
, th
is stud
y is
m
a
in
ly f
o
cusing
on
d
e
v
e
lop
i
ng
o
cean
en
erg
y
d
e
v
i
ce for h
a
rn
essin
g
an
d
u
tilizatio
n
of
M
a
l
a
y
s
i
a
n oce
a
n c
u
r
r
ent
c
h
a
r
act
eri
s
t
i
c
. A
du
ct
di
ff
use
r
has
been
p
r
op
ose
d
expe
ri
m
e
nt
al
ly t
o
e
nha
nce t
h
e
fl
o
w
velocity through turbine
r
unne
r
, whic
h
is suit
able
fo
r utilizing at Malaysian
Ocean
of l
o
w spee
d c
u
rre
n
t.
2.
R
E
SEARC
H M
ETHOD
2.
1. Desi
gn Co
ncepts
o
f
D
i
ffuser-A
u
g
mented
HA
MC
T
The desi
gn co
ncept
o
f
di
f
f
us
er augm
ent
e
d HAM
C
T
has
b
een de
vel
o
ped
and c
onsi
d
ere
d
t
o
be
m
o
re
suitable for Malaysian Ocean characteristics
.
HAMCT de
si
gn
principle is alm
o
st the sa
me basis as the wind
tu
rb
in
e tech
no
l
o
g
y
. Th
is can lead
to m
a
n
y
ad
v
a
n
t
ag
es
b
ecau
s
e
wind
turb
in
e is a
well-d
e
v
e
lop
e
d techn
o
lo
g
y
.
Neve
rt
hel
e
ss
, i
n
or
der
t
o
desi
gn
a ‘
w
i
n
d t
u
r
b
i
n
e
’
as m
a
ri
n
e
cur
r
e
n
t
t
u
rbi
n
e, se
ve
ral
co
nsi
d
e
r
at
i
o
n
s
m
u
st
be
t
a
ken t
o
m
a
ke
sure
t
h
e
de
vel
o
pm
ent
i
s
sui
t
a
b
l
e fo
r m
a
ri
ne c
h
arct
ri
st
i
c
s.
M
odi
fi
cat
i
onss
h
o
u
l
d
be
car
ri
ed
out
t
o
mak
e
su
re the tech
no
log
y
app
lied
can
withstan
d
th
e m
a
ri
ne en
vi
r
onm
en
t
.
The co
nce
p
t
desi
g
n
o
f
H
A
M
C
T
i
n
Evaluation Warning : The document was created with Spire.PDF for Python.
I
J
PED
S
I
S
SN
:
208
8-8
6
9
4
Au
gme
n
t
e
d
Di
f
f
user f
o
r
Hori
z
ont
al
Axi
s
M
a
r
i
ne C
u
r
r
ent
Tu
rbi
n
e
(
A
.H
.A.
El
bat
r
an)
23
7
t
h
i
s
st
u
d
y
(
F
i
g
ures
1
an
d
2
)
has
bee
n
deve
l
ope
d t
o
ca
pt
u
r
e as m
u
ch
as
ene
r
gy
f
o
r M
a
l
a
y
s
i
a
n Ocea
n.
Th
e
desi
g
n
m
o
st
l
y
ap
pl
i
e
d
p
r
evi
ous
HAM
C
T
desi
g
n
c
o
ncep
t
can
be
use
d
f
o
r
ha
rne
ssi
n
g
M
a
l
a
y
s
i
a
n c
u
r
r
ent
energy.
Fi
gu
re 1.
Di
f
f
u
ser-
Au
gm
ent
e
d
c
once
p
t
fo
r M
a
l
a
y
s
i
a
n
oce
a
n HAM
C
T
This desi
gn is
attached at the seabed wit
h
gra
v
ity
base struct
ure.
During
th
e op
eration
,
th
e fix
e
d
g
r
av
ity b
a
se stru
ct
u
r
e an
d
the fix
e
d
cab
l
e will su
pp
or
t th
e tu
rb
in
e
for h
a
rn
essing
energ
y
fro
m
th
e water
cu
rren
t. Th
e fi
x
cab
l
e will also
act as a m
o
oring
system
fo
r th
e fl
o
a
tin
g stru
ct
u
r
e. Th
e desig
n
also
allows the
cy
l
i
ndri
cal
d
u
c
t
t
o
bec
o
m
e
rem
ovabl
e. T
h
e
t
u
r
b
i
n
e
rot
o
r c
onsi
s
t
s
o
f
d
u
ct
ed
di
ff
use
r
,
rot
o
r
h
o
l
d
e
r
,
rot
o
r, a
n
d
co
n-alik
e hub
. Th
e ho
ld
er is u
s
ed
to
in
cl
ud
e th
e ro
tor,in ad
d
ition
t
h
e
electric cab
le can
b
e
p
l
aced
insid
e
th
e
hol
der
.
Fi
gu
re 2.
Tu
r
b
i
n
e desi
g
n
c
o
nc
ept
Th
e ro
tor d
e
si
g
n
is th
e m
o
sti
m
p
o
r
tan
t
p
a
rt in
th
is HAMCT for lo
w sp
eed
water cu
rrent. Th
ere is
a
need
of s
p
ecial intention for
the ro
t
o
r d
e
sign
b
ecau
s
e it is
wo
rk
ed
in
fluctu
atio
n
of curren
t sp
eed
and th
e
current appears in m
u
lti dir
ections. The rot
o
r
desi
gn should also
able
t
o
withstand t
h
e
ocean current l
o
adi
n
g
on t
h
e bl
a
d
es.
The
desi
g
n
s fe
at
ure a
ppl
i
e
d a
r
e fi
xe
d
pi
t
c
h
4 sy
m
m
e
t
r
i
c
blades r
o
t
o
r,
whi
c
h are easi
e
r f
o
r t
h
e
con
s
t
r
uct
p
r
oc
ess.
N
u
m
b
er
of
bl
a
d
es a
p
pl
i
e
d i
s
rel
a
ted to
t
h
e torq
u
e
ch
aracteristic, tip
-sp
e
ed
ratio
,
weigh
t
,
an
d pow
er. Fou
r
b
l
ad
es
w
e
r
e
ch
osen b
a
sed
on
w
i
nd
tu
rb
in
e tech
no
log
y
which
stud
ied
in
referen
ce [22
]
.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
S
SN
:
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088
-86
94
I
J
PED
S
Vo
l. 7,
No
.
1,
Mar
c
h
2
016
: 2
3
5
–
24
5
23
8
2.
2. Desi
gn
Pr
ocedure
s
B
a
sed o
n
t
h
e
conce
p
t
de
si
g
n
devel
ope
d, t
h
e det
a
i
l
s
desi
g
n
was m
a
de.
The d
e
t
a
i
l
s
desi
gne
d o
f
t
h
e
cur
r
ent
sy
st
em
consi
s
t
s
o
f
bl
ades desi
gn
, d
u
ct
desi
g
n
an
d
di
ff
user
desi
g
n
. The m
a
i
n
conce
r
n i
n
t
h
e bl
ades
d
e
sign
is th
e lift an
d
d
r
ag
ch
aracteristics, since it is
stro
ng
l
y
rel
a
t
e
d t
o
t
h
e t
o
rq
ue t
h
at
wi
l
l
be pr
od
uce
d
by
t
h
e
tu
rb
in
e.
Th
e
m
o
st effectiv
e p
a
ram
e
ter for HAMCT is t
h
e lift force
whilst dra
g
forc
e can
be c
onsi
d
ere
d
a
s
waste force that sh
ou
ld
b
e
kep
t
as lo
w as po
ssib
l
e.
Based
o
n
th
e literature stu
d
y
, it was fou
n
d
th
at, the
m
o
st
id
eal b
l
ad
es sectio
n
s
fo
r t
u
rbin
e b
l
ad
es in
th
e d
e
v
e
lop
m
e
n
t stag
e is th
e sy
mmetric NACA airfo
il sectio
n
s
.
Thus, t
h
e lift (Cl) and dra
g
c
o
effici
ent
(C
d)
fo
r se
ri
es o
f
NAC
A sy
m
m
et
ri
c sect
i
ons
ha
ve
been
st
u
d
i
e
d
usi
n
g
DES
I
G
N
F
O
I
L
soft
ware
[
23]
,
as
sh
o
w
n
in Figu
re (3
).
It was noticed
that the selected
di
f
f
ere
n
t
N
A
C
A ai
rf
oi
l
sect
i
ons
have
near
l
y
t
h
e sam
e
m
a
xi
m
u
m
C
l
,
but
NAC
A 0
0
12
reco
r
d
ede
d
t
h
e hi
ghest
val
u
e of l
i
f
t
coe
ffi
c
i
ent
.
It
al
so
has
m
a
xim
u
m
dr
ag coefficient. Hence,
NAC
A
0012 i
s
the m
o
st pre
f
era
b
le section that can
be
ut
ilized for the t
u
rbine
bl
ades
according t
o
the lift
force resu
lts, esp
ecially it als
o
h
a
s a ligh
t
er
wigh
t. Howe
v
e
r, th
e
h
i
gh
est valu
e o
f
t
h
e dra
g
force ca
n di
minish
this adva
nda
ge
.Based on t
h
e
expecte
d
l
o
ads
from
seaw
ater, NAC
A
0014
airfoil secti
o
n
was t
h
e m
o
st s
u
itable
optionbecause
it is thicker tha
n
NAC
A
0012. Although, t
h
e
0016 a
n
d 0020 has
thicke
r
bla
d
es a
n
d lowe
rCd at
higher a
ngles
of attack tha
n
0014
, but the
Malaysian ocean with low s
p
eed curre
nt ne
eds a turbine
with less
wei
g
ht
, t
hus
, cho
o
si
ng t
h
i
c
ke
r bl
ades (
0
01
6
or 0
0
2
0
) ca
n i
n
crease wei
g
h
t
of t
h
e ove
ral
l
desi
gn. F
o
r t
h
ese
reaso
n
N
A
C
A
00
1
4
was
c
h
os
en fo
r
t
h
e
bl
a
d
es
desi
gn
.
(a)
(b
)
Fi
gu
re 3.
and
for
v
a
ri
o
u
s
NACA symmetric airfo
il section
s
Evaluation Warning : The document was created with Spire.PDF for Python.
I
J
PED
S
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S
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:
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8-8
6
9
4
Au
gme
n
t
e
d
Di
f
f
user f
o
r
Hori
z
ont
al
Axi
s
M
a
r
i
ne C
u
r
r
ent
Tu
rbi
n
e
(
A
.H
.A.
El
bat
r
an)
23
9
Fi
gu
re 4
sh
o
w
s t
h
e det
a
i
l
s
of
t
h
e H
A
M
C
T augm
ent
e
d di
f
f
use
r
sy
st
em
, whi
c
h c
o
n
s
i
s
t
s
o
f
f
o
u
r
pa
rt
s:
in
let d
i
ffu
s
er
o
r
funn
el to
’cap
ture’ th
e
flo
w
in
t
o
d
e
si
g
n
e
d
turb
i
n
e,
th
e du
ct cylin
d
e
r to
un
iform an
d
con
s
ent
r
at
e t
h
e wat
e
r fl
o
w
t
h
r
o
ug
h t
h
e t
u
r
b
i
n
e a
nd t
h
e
o
u
t
l
e
t
di
ff
user t
o
re
duce
wa
ke
of t
h
e m
ovi
n
g
fl
ui
d
passi
n
g
t
h
e t
u
r
b
i
n
e a
n
d t
h
e
t
u
rbi
n
e c
o
n
f
i
g
ur
at
i
on
whi
c
h c
o
nt
ai
ns
4
bl
ades
, st
at
i
c
h
u
b
,
m
ovi
ng
h
u
b
, a
n
d
rot
o
r
hol
der
.
T
h
e
ov
eral
l
di
m
e
nsi
ons
of
t
h
e
di
f
f
u
s
er a
ugm
ent
e
d
HAM
C
T
a
n
d i
t
s m
odel
can
be
seen
i
n
Ta
bl
e
1.
Fi
gu
re
4.
C
o
nc
ept
D
u
ct
sy
st
e
m
for t
h
e
p
r
o
p
o
se
d H
A
M
C
T
Tabl
e 1. Det
a
i
l
desi
gn
pa
ram
e
t
e
rs
Parts
Details
Model
Scale
I
n
let Diffuser
L
e
ngth
1.
433
m
Outer
Dia
m
eter
1.
400
m
Outlet Diffuser
L
e
ngth
1.
490
m
Outer
Dia
m
eter
1.
360
m
Duct Cy
linder
L
e
ngth
0.
700
m
Diam
eter 0.
917
m
Blades Diam
eter
0.
833
m
Actual Radius
0.
333
m
Hub
M
oving Hub Diam
eter
0.
087
m
M
oving Hub lengt
h
0.
087
m
Static Hub Legth
0.
12
0
2.
3. HA
M
C
T Mo
del
C
o
n
s
tr
uctio
n
The m
odel
const
r
uct
i
on
pr
oc
ess fo
r t
h
e au
g
m
ent
e
d di
ff
use
r
HAM
C
T
i
n
t
h
e cu
rre
nt
rese
arch
wo
rk
was
d
i
v
i
d
e
d
i
n
to
th
e
bu
ild
ing o
f
th
e t
u
rb
in
e
ro
t
o
r, cylin
d
e
r
d
u
c
t, and
t
h
e diffusers
du
cts.
All th
e co
n
s
t
r
uctio
n
process wa
s done at Mari
ne
technol
ogy ce
nter (MTC), Unive
r
siti
Teknologi Malaysia
(UTM).The turbine
co
nsists of
4
blad
es run
n
e
r
,
static h
u
b
, m
o
vin
g
hu
b, an
d ro
tor
ho
l
d
er
. Blad
es and
static hu
b w
e
r
e
m
a
d
e
o
f
wo
o
d
, P
V
C
f
o
r
t
h
e m
ovi
ng
hu
b, t
w
o
beari
ng
and st
ai
nl
ess st
eel
shaft
a
s s
h
o
w
n i
n
Fi
g
u
r
e
5
.
C
y
l
i
nder
duct
w
a
s
con
s
t
r
uct
e
d
usi
ng
fi
be
r-
gl
ass
and t
h
e m
oul
d
was c
onst
r
uct
e
d u
s
i
n
g t
h
i
c
k
pl
y
w
o
o
d
wi
t
h
wo
o
d
f
o
r t
h
e
m
oul
d
st
ruct
u
r
e.
The
sam
e
approac
h
i
ng
was
d
o
n
e f
o
r
t
h
e
di
f
f
use
r
s
d
u
ct
.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
S
SN
:
2
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94
I
J
PED
S
Vo
l. 7,
No
.
1,
Mar
c
h
2
016
: 2
3
5
–
24
5
24
0
Fi
gu
re 5.
The
c
onst
r
uct
i
o
n p
r
o
cedu
r
es
2.
4. E
x
peri
me
ntal
Ap
par
a
tu
s
There a
r
e t
h
re
e t
y
pes of m
o
del
t
e
st
i
ng pr
o
pos
ed i
n
o
r
der
t
o
det
e
rm
i
n
e
t
h
e HAM
C
T
p
e
rf
orm
a
nces
whic
h are Free
Tow M
odel T
e
st, Ducte
d
T
o
w Model Test
and
Ducted
Diffuser T
o
w Model Test as shown i
n
Fi
gu
re
6. T
h
e
equi
pm
ent
for
t
h
i
s
m
odel
t
e
st
i
ng a
r
e t
o
wi
ng
Tan
k
,
u
nde
rwat
er
cam
era, l
a
pt
o
p
,
no
n-
c
ont
act
Tachom
eter, angle
ruler, G
- clam
p
and ruler t
o
get a
n
accurate
data for RPM, t
o
rque
a
n
d powe
r
, t
h
ese
equi
pm
ent
s
i
n
st
al
l
a
t
i
on are s
h
ow
n i
n
Fi
gu
re
7. T
h
e
res
u
l
t
s
of
p
o
we
r, t
o
r
q
ue a
n
d
ef
fi
ci
en
cy
were
det
e
r
m
i
n
ed at
di
ffe
re
nt
cu
rre
nt
s
p
eed
an
d
v
a
ry
i
n
g
y
a
wi
n
g
angl
es
.
Hence
,
t
h
e s
p
ee
ds
of
t
h
e wat
e
r c
u
r
r
e
n
t
s
f
o
r t
h
e
H
A
M
C
T
m
odel
can b
e
f
o
u
n
d
i
n
Ta
bl
e
2.
B
a
sed
on t
h
e
det
a
i
l
e
d
desi
gn
an
d c
o
n
s
t
r
uct
i
o
n
p
r
o
ced
ures
o
f
t
h
e
a
ugm
ent
e
d
di
ff
user
H
A
M
C
T
d
e
v
i
ce, it is essen
tial to
test it in
ter
m
o
f
p
e
rf
o
r
m
a
nce. The c
onst
r
uct
e
d m
odel
was t
h
e
n
t
e
st
ed f
o
r
p
e
rform
a
n
ce an
d fu
rt
h
e
r
power
pred
iction assessm
en
t.
Fig
u
re
8
illu
strates th
e cu
rren
t system
d
u
r
i
ng
measurem
ent and obse
rvation.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
J
PED
S
I
S
SN
:
208
8-8
6
9
4
Au
gme
n
t
e
d
Di
f
f
user f
o
r
Hori
z
ont
al
Axi
s
M
a
r
i
ne C
u
r
r
ent
Tu
rbi
n
e
(
A
.H
.A.
El
bat
r
an)
24
1
Fig
u
re
6
.
(A) Free tow m
o
d
e
l
test, (B)
Du
cted
to
w m
odel te
st (C)
D
u
cted
d
i
ffu
ser t
o
w
m
odel test
Fig
u
re
7
.
Model settin
g
at th
e to
wi
n
g
carriage
Tabl
e
2. C
o
r
r
e
s
po
n
d
e
n
ce
vel
o
ci
t
y
fo
r sy
st
e
m
m
odel
Test Case
Curren
t Veloci
ty
(
m
/s)
1 0.
42
2 0.
63
3 0.
84
4 1.
05
Evaluation Warning : The document was created with Spire.PDF for Python.
I
S
SN
:
2
088
-86
94
I
J
PED
S
Vo
l. 7,
No
.
1,
Mar
c
h
2
016
: 2
3
5
–
24
5
24
2
Fi
gu
re
8.
A
u
g
m
ent
e
d Di
ff
us
er
HAM
C
T
de
vi
ce t
h
ro
u
g
h
o
b
ser
v
at
i
o
ns
3.
RESULTS
A
N
D
DI
SS
CU
S
S
ION
Th
e m
a
in
g
o
a
l
o
f
t
h
e presen
t work
was i
n
vestig
a
ting the
perform
a
nce char
acteristics of
augm
ented
diffuse
r
system to increase the effec
tivenes
s of t
h
e tidal current
horizont
al
turbi
n
e efficiency whic
h used i
n
lo
w
v
e
l
o
city r
e
g
i
on
s. Th
is was d
o
n
e
thr
ough
m
easu
r
in
g
the p
e
r
f
or
m
a
n
ce p
r
o
p
e
r
ties o
f
t
u
rb
in
e
p
e
rf
or
man
ce.
Th
is is
d
e
scribed
thro
ugh
th
e
Equ
a
tio
n b
e
l
o
w:
PT
∗
ω
[
1
]
Whe
r
e P i
s
t
h
e out
put
po
we
r, T re
p
r
esent
s
t
h
e o
u
t
p
ut
t
o
r
que
,
ω
is th
e an
gu
lar velo
city. Mo
reo
v
er
t
o
r
que
i
s
gi
ven
by
:
T=
F
*
r
[
2
]
Whe
r
e
r i
s
bl
ad
e ra
di
us a
n
d
F
is liftin
g
forcewh
i
ch
rep
r
esen
ts in
Equ
a
tio
n [3]:
F
0
.
5
ρ
U
A
C
[
3
]
Whe
r
e
ρ
is water
d
e
n
s
ity, U
is
a free flow v
e
lo
citity,
A
is turbine
blades areaa
nd
C
is lift
coefficient.
En
hanci
ng t
h
e
fl
ow s
p
eed ca
n i
n
crease t
h
e
l
i
f
t
i
ng fo
rces a
s
wel
l
as pow
er ge
nerat
e
d
,
whi
c
h i
s
t
h
e
main
in
terest
of th
e Malaysia sites.
The power c
o
e
fficient (C
p)
of turb
in
es
was
u
s
ed
to
reflect th
e tu
rb
ine
perform
a
nce, as presente
d in
Equ
a
tio
n (4
):
∗
[
4
]
From
the
m
o
del testing conducted, t
h
ere are two m
a
jor characteristics ne
eded t
o
be
obs
erve
d whic
h
a
r
e
th
e in
cr
e
a
s
in
g
f
l
ow
ch
ar
ac
te
r
i
s
tic
s
a
n
d flo
w
con
c
e
n
t
r
ation
due t
o
yawing a
n
gle.
Inc
r
easing the
spe
e
d is
a
crucial factor in designing for Mala
ysian Ocean low s
p
ee
d curre
n
t appe
ar
ance
. Ducted diffuser ca
n increase
the flow
of the
curre
nt and can redi
rect the flow pe
rpe
n
d
i
cu
lar to
th
e ro
tor b
l
ad
e an
d ca
n increase the
flow at
the duct intake. Increasi
ng
flow c
h
aracte
r
istic theoretically can be ach
i
e
ved usi
n
g d
u
ct
ed di
ff
use
r
whi
l
e
conce
n
t
r
at
i
n
g
f
l
ow
by
a
ppl
y
i
n
g
duct
e
d cy
l
i
n
der
su
rr
o
u
n
d
e
d
t
h
e
bl
ade t
u
r
b
i
n
e.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
J
PED
S
I
S
SN
:
208
8-8
6
9
4
Au
gme
n
t
e
d
Di
f
f
user f
o
r
Hori
z
ont
al
Axi
s
M
a
r
i
ne C
u
r
r
ent
Tu
rbi
n
e
(
A
.H
.A.
El
bat
r
an)
24
3
Fi
gu
res
9
sh
o
w
s t
h
e t
h
e
va
ri
at
i
ons
o
f
o
u
t
p
ut
po
we
r
at
different y a
w
ing a
n
gle in case
of
free tow and
d
u
c
ted
tow.
It
can
b
e
seen
cl
early th
at th
e ap
p
lication
of
ducted t
u
rbine a
r
e really
sign
ifican
t to
in
crease th
e
produce
d
power from
the cu
rre
nt syste
m
because the
duc
t able to in
cre
a
se flowing speed of the fl
uid and
conce
n
trate t
h
e
flow t
o
wa
rds t
h
e
blades
of the turbine
.
Mu
lti-d
i
rectional cu
rren
t
appro
a
ch
ing
th
e t
u
rb
in
e
can
b
e
p
r
ed
icted
fro
m
th
e ex
p
e
rim
e
n
t
s and
th
e
results is shown in Figure
(9). Th
e power increased
with th
e increm
ent of yawing an
gle until reache
d
to the
m
a
xim
u
m
val
u
e at
20°, a
f
t
e
r
t
h
at
t
h
e p
o
we
r
was su
d
d
e
n
l
y
dr
o
ppe
d.
In t
h
e ot
her
w
o
r
d
s,
t
h
e pre
s
ence
o
f
d
u
ct
were
not e
ffect
ing t
h
e
flow s
p
eed at
0°
y
a
wi
ng
an
gl
e,
h
o
w
ever
, at
a
b
out
20
°
de
gree
o
f
y
a
wi
ng
, t
h
ere
wast
he
opt
i
m
u
m
angl
e whi
c
h rec
o
r
d
e
d
t
h
e m
a
xim
u
m
powe
r
, a
nd i
t
was l
e
sser w
h
en i
t
reac
he
d at
30°
de
gree y
a
wi
n
g
angl
e. M
o
re
ov
er, t
h
e m
a
xim
u
m
power
out
put
o
f
9
0
W
i
n
case of
duc
t
e
d t
o
w at
2
0
°
y
a
wi
ng an
gl
e
but
t
h
e
si
gni
fi
ca
nt
p
o
w
er ca
n
be
ha
r
n
esse
d i
n
case
of
free
t
o
w i
s
78
w
at
1
0
° c
u
rre
nt
ap
p
r
oac
h
.C
o
n
seq
u
e
n
t
l
y
, i
t
was
believed that
duct wa
s a
n
effe
ctive spee
d-augm
entation de
vice
Fig
u
re
9
.
Po
tential o
f
h
a
rn
essi
n
g
en
erg
y
in
m
u
lti-d
i
rection
a
l
curren
t
appro
a
ch
es
The
free
to
w,
d
u
cted
to
w,
fo
rwa
r
d
di
ff
us
er a
n
d
aft
di
f
f
use
r
c
o
nfi
g
u
r
at
i
on case
s
w
e
re t
e
st
ed
at
diffe
re
nt vari
o
u
s cu
rre
nt s
p
ee
d. T
h
e
pe
rformance charact
eristics curves
of
tested cas
es
are shown in
Figures
1
0
and
11
.
I
t
was ob
serv
ed
that th
e ou
tpu
t
po
w
e
r
lead
s
to increase
with the increase
of
flow curre
nt s
p
e
e
d for
all tested cases as shown i
n
Figure 10. M
o
reover, th
e m
a
xi
m
u
m
power
out
put
rec
o
rde
d
f
o
r t
h
e aft
di
ff
user
case whic
h wa
s slightly around
250
W at a current s
p
ee
d 1
.
0
5
m
/
s. On t
h
e
ot
her
ha
nd
, t
h
e
po
wer
cur
v
e
indicated that forward diffuse
r case
was t
h
e seco
nd pe
rfe
ct
con
f
i
g
urat
i
o
n
whi
c
h reco
r
d
e
d
m
a
xim
u
m
power o
f
alm
o
st
190
W.
Thi
s
i
s
whi
l
e
t
h
e cases free
t
o
w an
d d
u
ct
e
d
ha
ve sh
ow
n
po
o
r
charact
e
r
i
s
t
i
c
s co
m
p
ared
wi
t
h
t
h
e
ot
her
t
w
o
casesw
h
i
c
h
t
h
e
m
a
xim
u
m
out
put
p
o
we
r
was
nea
r
l
y
16
6
W
i
n
t
h
e
cases
o
f
fre
e t
o
w a
n
d
duct
e
d
to
w.
An early assum
p
tion was that the forwa
r
d arrang
em
ent
can gives a large effect for the speed
in
crem
en
t. Howev
e
r, it tu
rns o
u
t
to
b
e
the aft arra
nge
m
e
nt
was m
o
re effect
i
v
e
rath
er than
th
e
fo
rward
arra
ngem
e
nt
. Thi
s
sh
oul
d be d
u
e t
o
t
h
e effect
of t
h
e cu
rre
nt backflow that affect th
e whol
e syste
m
, whilst aft
arra
ngem
e
nt
re
duci
n
g
wa
kes
of
t
h
e
fl
o
w
a
n
d
di
rect
i
n
g t
h
e
o
u
t
f
l
o
w sm
oot
hl
y
.
The power Coefficient “efficiency”, Cp, wa
s consi
d
er
a
b
ly higher for aft diffuser case for all curre
nt
sp
eed
stu
d
i
ed
in
th
is work
, as sh
own
in
Fi
gu
re 11
.
It is
in
t
e
restin
g
th
at the
m
i
n
i
m
u
m Cp
fo
r aft d
i
ffu
s
er test
was hi
g
h
e
r
t
h
a
n
t
h
e m
a
xim
u
m
C
p
for t
h
e ot
he
r cases, t
h
i
s
pro
v
e
d
t
h
at
t
h
e im
port
a
nce
of usi
ng t
h
e
d
i
ffu
ser
after th
e du
ct t
o
g
e
t sign
ifican
t power
e
x
t
r
a
c
t
i
on.
Fu
rt
he
r
m
ore, t
h
e m
a
xi
m
u
m
Cp obtained for
aft
diffuser case
was
0.
58 at
0.
84 m
/
s curre
nt
spee
d,
whi
c
h
were m
o
re t
h
an 1
.
3
,
1
.
6
an
d 1
.
7 t
i
m
es t
h
e
m
a
xim
u
m
Cp f
o
r
fo
rwa
r
d diff
us
er, d
u
cted
t
o
w
and free tow
re
spectively.
0
10
20
30
40
50
60
70
80
90
100
0
5
10
15
20
25
30
Free
Tow
Ducted
Tow
Power
(W)
Yawing
Angle
(degree)
Evaluation Warning : The document was created with Spire.PDF for Python.
I
S
SN
:
2
088
-86
94
I
J
PED
S
Vo
l. 7,
No
.
1,
Mar
c
h
2
016
: 2
3
5
–
24
5
24
4
Fig
u
re
10
. Th
e po
ten
tial of
h
a
rn
essi
ng
th
e
power at differe
n
t spee
d c
u
rrent
approachi
n
g
Figure
11. t
h
e
powe
r c
o
efficient at
di
ffe
rent current spee
d for
all
cases
4.
CO
NCL
USI
O
N
Th
e
o
b
j
ectiv
e o
f
th
is
wo
rk wh
ich
was t
o
d
e
si
g
n
a
horizon
tal ax
is marin
e
cu
rren
t tu
rb
i
n
e was
pu
rs
ued
.
i
t
wa
s st
udi
e
d
t
h
e
p
r
evi
ous
de
vel
o
ped
H
A
M
C
T
devi
ce,
t
h
e fl
o
w
co
nce
n
t
r
at
i
n
g de
vi
ces as
w
e
l
l
as
spee
d i
n
c
r
easi
n
g
d
e
vi
ces,
a
n
d t
o
st
udy
fr
o
m
wi
nd t
u
r
b
i
n
e t
ech
nol
ogy
.
The
desi
gn
o
f
H
A
M
C
T
has
bee
n
d
e
v
e
l
o
p
e
d
b
a
sed
o
n
t
h
e
literatu
re
st
u
d
i
ed
. It
con
s
ists o
f
4
b
l
ad
es ro
to
r
u
s
ing
NACA
00
14
d
e
sign
p
r
o
f
il
e
sur
r
o
u
n
d
e
d by
a
cy
l
i
nder di
f
f
use
r
wi
t
h
an at
t
achm
e
nt
of diffuse
r
to i
n
crease the s
p
eed flow.
A m
o
del was
b
u
ilt to
pred
ict th
e p
e
rfo
r
m
a
n
ce o
f
t
h
e d
e
si
gn
ed
t
u
rb
in
e and
to
st
u
d
y
th
e
effectiv
en
ess
of th
e
d
u
c
ted
wh
en
ap
p
lied
t
o
cu
rren
t
tu
rb
in
e.
It was fo
und
th
at wh
en
u
tilizin
g
aug
m
en
ted
-
d
i
ffu
s
er aro
und
ho
rizo
n
t
al cu
rrent
tu
rb
in
e, th
e
velo
city th
ro
ugh
th
e tu
rb
in
e an
d
aug
m
entation diffuser and the rotor was incre
a
s
e
d. T
h
e
m
a
xim
u
m
power
out
put
i
n
c
r
eased
fr
om
nearl
y
16
6
W
i
n
case o
f
f
r
ee
fl
ow t
o
sl
i
g
ht
l
y
above
2
49
W f
o
r
augm
ented-
di
ffuser, also the Coeffi
cie
n
t of
powe
r also increase
d
by
1.7 tim
e
s for this case. Di
ffuser
0
50
100
150
200
250
300
0.4
0
.6
0.8
1
1.2
Free
Tow
Ducted
Tow
Forward
Diffuser
Aft
Diffuser
Power
(W)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.4
0
.6
0.8
1
1.2
Free
Tow
Ducted
Tow
Forward
Diffuser
Aft
Diffuser
Current
Velocity
(m/s)
Power
Coefficient
(Cp)
Current
Vel
o
city
(m/s)
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