Some experiments on two-dimensional hydrofoils in polymer solutions

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3 JUU 1975

ÁICH1E

Some Experiments on Two-Dimensional Hydrofoils in Polymer Solutions

Hiroshi Kawada and Tetsuo Tagori

-Presented at annual meeting of Japan Society of Mechanical Engineers on fluid mechanics and fluid machinery at 28 Aug. 1973, and No.1 Meeting of Japan Towing Tank Committee at

9 Apr. 1973.

Summary

It was obtained by T. Kowalski that., at the propeller open tests in polymer solutions, the torque increased and the thrust and efficiencyreduced. And the reduction of revoku-tion of blade wheel currentmeter was experienced at many laboratories in polymer solutions. To investigate this phenomen the measurements of pressure distribution on

hydrofoils in polymer solutions and flow observations carried out in circulating water channel. And the lift and form drag were obtained from the results of pressure distribution

measurements.

Hydrofoil

Hydrofoils used in experiments, had following particulars.

Secion

: NACA 0012, NACA 66-012

Chord length: 400 mm Span : 1,000 mm

Material : metacrylic resin

Turbulence stimulation:, stud at 100 inn from leading edge

Polymer

Polyacrylarnide(Separan AP-30) was used in o, 50, lOO, 150, 200, 300, 400

i

Lab.

y.

ScheepsbouwkunJe

Technische Hogeschool

Deift

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t.

2

Apparatus

Fig. i shows the apparatus in circulating

_{water channel.}

The hydrofoil was installed vertically and

_{the fence was used}

to deduce the free surface effects.

_{The electro-magnetic type}

currectmeter(electro-magnetic type log for actual ships)

was

installed ahead of hydrofoil to adjust flow velocity,

and

removed in measuring time.

_{At flow observations, the tracer}

was air bubble blowed by compressor, amad mid part of span

of hydrofoil was lighted through the siLit.

Results

Figs. 2'.'7 show the pressure distrïbution.

Figs. 8 and 9 show the lift àoeffiient.

Figs. 10 and 11. show the lift coefficient and drag

coefficient excluding friction.

Figs. 12 and 13 show the results o

flow observations.

(Each plate in these Figs. was composedy connection of local

photographs.).

Fig. 14 shows the attack angle that the separation

_occúrs

near the leading edge, detected by flow øbservation.

These results are summarised as follows.

The pressure of stagnation point ireases in

polymer

solutions.

The pressure distribution of hydroil varies in

polymer

solutions, even in small attack

ang.

The lift coefficient decreases and tthe form drag

_coef

fi-cient increases in polymer so1utior.

In polymer solutions, the separatiari near the leading

edge occurs at smaller attack angle than fresh

_water,

and it seems that longitudinal vorces fol.1'ows this

separation, at the concentration 'or

150. ppm

The attack angle that the separatim-i occurs near the

leading edge, increases slightly in dilute solutions,

and reduces as increasing polymer

_ncentration.

The effect of...sidewt1l apears at the larger

attack

angle th&n about 78 egrees in

iis experiment.

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0. b I o o

n.

o O

50 Ioo

A 300

À

400. i

o

.- /

7o ,I 4.00

t-Jlo4(-/

)#

Maioreter Fence E o o o. s. s.

/

V

/

NACA

data'

- - - _smooth NACA 0012, V=0.990

_rn/s

Hyofoil 1töt.

tbe.

rL1CaMIera. t I ofloM

/

,__-oi

_'

-I

1.0

AA

A

attj.

_{-- ...}

ug

Fig. 8 _{Lift coefficient;}

L

H®I

standard roughness Flow

4i.tion

, t t - et

Elecim mqiict:

Currentineter f I Floyd I b diyge.tio

I.

Fig. 1 _Apparatus

ç

CL 0.5

rrm

00 +io

A 3oo

£400

ri-ò... 1 NACA data -- smooth - - .. standard, roughness I _I

___._

20

0 1G ... 20

attack angle (deg.)

Fig. 9 Lift coefficient,

NACA 66-Ol2, V=0.990 rn/s

'I

e

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r

r .

e o

a

so

y ¡go -I..o

__-o-øo

Fig. 2 Pressure distribution, NACA

0012, =0°,V=O.990m/s -r

4-j

f,

t

o Op».

X ¡50 ppa»

.300ppôn

,,v .NACA 0012, ct=8°, V=O.990 in/s o O

x IO

I

300

I'

Fig. 6 Pressure distribution, i' F'..

rv2

Fig. 3 Pressure distribution; NACA 0012, c=0 _{V=0 .990 rn/s} pp,' Ö _Q 300

X 400

o

V=0.990. in/s -X__ _o s p-aç___

Fig. 5 Pressure distribution,

NACA 0012, ct=12°,

F'?"

V1,

R

r

o

₀

_D.6S

_L2X(o

150 o.o'

09c0

NACA 66f-012, OE=6°, Fig. Pressure distribution,

-. V=0.990 in/s

:NACA 66-o12, a=iO°

Pressure distribution, Fig. 4

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0.0 E n I0 o

rr

0

so X 100

t150

6 20o

V 300

o400

¿ 1

o

I

Fig. 10 _{Lift coefficient and form}

drag coefficjent,.NACA

_0012,.

v=Ò.990 rn/s L

15

xxi

oö _2,Oo _3ôo _4oa

conòentration (ppm)

Fig. 14 _{Attack angle that separation}

occurs near the leading

edge NACA 0012 V=0

V

Lo

Maximum value of attack angle that separation 1)

occurs near theleading edge.

g

¿ Minimum value of _{attack angl.e that separation} occurs near the leading edge.

Fig. 1L Lift _{coefficient and} form drag coefficient, NACA 66i-012, V=0.99a'm/s