The wake field - basic information for propeller design

3 SEP. 9k

ARCHEF

SYMPOSIUM ON

"HYDRODYNAMIC5 OF SHIP AND OFFSHORE PROPUL5ION SYSTEMS"

HØVIK OUTSIDE OSLO, MARCH 20.-25.,1977

"THE WAKE FIELD- BA5C INFORMATION FOR PROPELLER DESIGN"

By

Klaus J. Meyne

THEODOR ZEISE, Ships' Propellers, Hamburg

SPONSOR: DET NORSKE VERITAS

Ref.:PAPER 16/2 - SE5SION 2

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THE WAKE FIELD - BASIC INFORMATION FOR PROPELLER DESIGN by Klaus J. Meyne, THEODOR ZEISE, Hamburg

ABSTRACT

It is very important to be able to make as accurate as

possible a prediction of the behaviour of the propeller

while the ship and propeller are still in the design stage.

The basic information, both for the design of the propeller

itself and for calculating the hydrodynamic forces and moments that will act on the propeller in the wake field, is provided by the wake field.

Comparative calculations for the wake fields of three ships have been carried out both on the model scale and on the estimated full scales these involved analyses of the wake fields and the calculation of the fluctuating forces and moments acting on the propeller.

An account is then given of the development of three different wake field families by the systematic variation of a reference

wake field. Comparative calculations have been performed

to investigate the effect of the wake peak at the 12 o'clock

2-i . INTRODUCTION

A thorough understanding of the vibration behaviour is of decisive importance in the design of a modern ship. The shipowners are constantly specifying the use of ever-higher powers, while at the same time they have a clear preference on economic grounds for single-screw ships. Therefore the

design o-F the propeller assumes increasing importance because the propeller working in the wake field is one of the sources of vibration.

The exciting forces and moments produced by the propulsion machinery and the propellers have also increased as the

installed power has risen. Since in many cases the ratio of machinery power to the mass of the ship has incrdased, it has become of fundamental importance that there should be a thorough understanding of the vibration behaviour.

It is therefore now more essential than ever to be able

to make predictions regarding the behaviour of the propeller

in the wake field with the greatest possible accuracy while the ship and the propeller are still in the design stage. To solve these problems the design engineer has available a variety o-F calculation methods, backed by his own experience. O-F major assistance in this work are suitable computer programs, since

the results are available quickly, and it is possible to

perform systematic parametric studies. Analyses and calculations of the wake field are used in the first place to enable the

propeller that is being designed to be adapted as closely as

possible to the wake field. Then calculations are per-Forred

to enable the behaviour of this propeller, together with the hydrodynamic forces and moments that are produced in the wake

field, to be analysed.

In the main the experience of the design engineer consists

of having applied these calculations to a large number of ships of various types, and then to have studied their full-scale

-

3-2. 1HE WAKE FIELD AND THE DESIGN PARAMETERS

It should first be noted that propellers interact very

differently with a given wake field, depending on their design

loading coefficient (thrust loading coefficient

TH Since,

however, in nearly every case the propeller revolutions will

be specified by the shipbuilder and the engine maker, the

loading coefficient is not a design parameter. The remaining design parameters then are:

Diameter. For efficiency reasons the propeller diameter

can be varied only within narrow limits. Nevertheless some variation is possible in order to enable the propeller

to work in a desirable wake region or to avoid an undesirable

region. In comparison with the behaviour of the propeller

in an homogeneous field (open water test) in most of the

wake fields of single screw vessels a certain reduction o-F

the propeller diameter will be without considerable influence on the efficiency. There may, however, be a favourable

influence with regard to cavitation and vibration behaviour.

Number o-F blades. So far as hydrodynamic aspects are concerned, a knowledge o-F the magnitude of the harmonic components of

the wake field is the most important factor affecting the

propeller design. It is, however, also necessary to take into account the vibration characteristics o-F the hull and o-F structures adjacent to the propeller, as well as data

relating to the propulsion machinery (such as the number of

cylinders).

Radial pitch distribution. The selection of the pitch

distribution is decisive for the loading distribution, and

hence for all the characteristics of the propeller. By varying

the different loading distributions it is possible,with the aid of a computer, to obtain an optimum distribution for a

Radial skew distribution. A suitable choice of the skew

distribution of the propeller can influence the selection

of the wake regions in which it will work.

Radial variation of the blade section, camber, and blade

thickness will influence the cavitation characteristics.

3. CALCULATIONS

3.1 WAKE FIELD ANALYSES

A harmonic analysis is performed to determine the behaviour o-F a propeller in a wake -Field. The wake harmonics o-F the wake fields investigated are determined up to the 6th Order

over the radius of the propeller.

In order to obtain another criterion for the non-uniformity

of a wake field, a suggestion that originated from the HSVA /1/ was adopted, and a value (x) was calculated for all the

wake fields investigated in the -Following manner.

If at radius x the local in-Flow velocity in the plane of

the propeller is y, and the velocity of the model or the ship isv, then the dimensionless average value for the inflow

velocity at a radius will be

¿ It -1 Vm (x) =

-4

21

I o

From /1/ the average deviation from this average velocity at a

radius will then be

2 U 21 o d. V)

Vm

V.n

d.p

-5-A comparison with the harmonic components of the wake field

concerned shows that the introduction of _{(x) in this form} provides no significant new information. Viewed as a

character-istic o-F the inhomogeneity of a wake field it is very similar to the ist harmonic component.

3.2 CALCULATION OF THE LIFT COEFFICIENT ANO THE ANGLE OF _ATTACK The hydrodynamic forces and moments excited on the propeller

by the wake field are calculated at 50 _{intervals of the propeller} blade position by means of a quasi-static method /2/. The _method employed takes into account on the one hand the Goldstein

factors and the curvature corrections /3/ o-F the design theory for the optimum propeller, and on the other hand the

character-istics of the propeller blade sections as determined by the two-dimensional aerofoil theory.

In the case of the program that we have been using for _many years now it is possible to introduce the three-dimensional wake field. If only the axial field is available, _{a constant}

inclined in-Flow can be assumed for the tangential components of the wake -Field. This has been done in the _{case o-F all the} investigations reported in this paper.

The ogram calculates the local lift coefficients

0L' the loca)

angles of attack°

, and also the local cavitation numbers

for radii 0.3 R to 0.9 R at 5° intervals of _{the propeller blade} position which are, however, not discussed in this paper.

The results give an indication of the suitability of _{the radial}

pitch or loading distributions that have been _{selected [lift} coefficients _{and enable an estimate to be made of the local} danger of cavitation occurring _{on the pressure side of the blade}

[negative angles of attack) especially where several designs alternatives are being considered.

So far no calculations have been performed with a view to estimating the form, magnitude, and nature of the cavitation on the suction side. There seems no doubt, however, that a

consideration of the lift coefficients and the angles of attack in both the radial and the circumferential directions would enable a qualitative comparison to be made of the cavitation

that may occur on the suction side.

For comparison purposes the calculated lift coefficients and angles of attack are given for the upper blade positions CaD0 to either side of the 12 o'clock position) in all the examples given n this paper. An attempt will also be made to estimate

the pressure variations on the hull induced by the propeller, since a relationship exists between the lift coefficient and the bound circulation.

In addition, following a suggestion made by Dr. Weitendorf, it is the intention in the future to determine the radial

distribution of the bound circulation for the upper blade

positions in the wake field about the 12 o'clock position. It is hoped that this may enable one component o-F the pressure variations to be calculated.

3.3 CALCULATION DF THE HYDRODYNAMIC FORCES AND MOMENTS, THE

THRUST EXCOENTRICITY, THE STRESS DISTRIBUTION, AND THE BLADE DEFLECTIONS

As described in the preceding Section 3.2, the computer program will calculate all the individual forces and moments acting on

the propeller in the wake field. This enables the total forces

andntiments acting on the propeller shaft, corresponding tn the number o-F blades, to be determined, as well as the thrust

eccentricity.

In addition the program will calculate the radial stress distribution on the pressure and suction sides of the blade, and also the radial deformation o-F the propeller blade. All the

results are shown in tables or on diagrams in the following

In -Future a comparative survey of the propeller blade de-Flections

produced in the wake field will also be provided, as suggested

in an article by Schwanecke /4/.

4. COMPARISONS OF THREE PROPELLERS IN THE MODEL WAKE ANO

IN 1HE ESTIMATED FULL-SCALE WAKE

All the calculations referred to in the preceding Section 3 have been carried out for three ships, both in the nominal model wake field and in the estimated full-scale wake field.

Figs. i to 3 show a comparison o-F the two wake fields.

The Author gratefully acknowledges the courtesy of Messrs. Blohm + Voss, Hamburg, for making this information available.

Ships 1 and 2 are high-speed single-screw container ships,

(delivered in 1975 and 1959 respectively), while ship 3 is a

bulk carrier (delivered 1975). The most important criterion is the vibration behaviour, and in this respect ships 1 and 3

had very low vibration levels, whereas ship 2 suffered severe

vibration in one area of the afterbody which measurements clearly showed to be due to pressure variations _{on the shell} plating. The amplitudes measured on the shaft of this ship provided to be negligible.

Figs. 4 to B show a comparison o-F the first B harmonic orders of the wake field on the model scale and the estimated full scale for these three ships. In the case of ship i there was

agreement as to both order o-F magnitude and trend for nearly

all the harmonic components of both fields. Differences occurred in the case of ship 2, however, as regards both trend and order

o-F magnitude, and in the case of ship 3 the differences were

appreciable.

Ship i is fitted with a six-bladed propeller, while that on

ship 2 is five-bladed (see table 1). There was little amplitudes

in the shaft forces and moments on either ship. From a study o-F

the corresponding orders of the wake field this is _{also to be}

anticipated in view of their magnitude and the correlation

-B-Ship 3 is fitted with a four'-bladed propeller'. The low vibration levels achieved on the actual ship suggest that possibly the wake field has not been correctly converted, since there are deviations for almost all the harmonic

components. Conversion of the wake field for ship 3 is also

inevitably more difficult, since the hull form is fuller

than that of ships i and 2.

There is little point in comparing and judging two wake fields on either the model scale or the estimated full scale solely from a visual inspection (see, for example, Figs. i to 3J.

On this basis it might appear that the differences in the

wake field of ship i were larger than in ship 3.

Figs. 7 and B show the radial distribution of the average velocity value ô (x), as defined in Section 3.1, for the

three wake fields on the model scale and estimated full scale. There is a marked similarity with the values for the ist

harmonic components, and these figures provide no new information.

Figs. 9 to 14 show the calculated lift coefficients and

angles of attack cX° for the upper blade position. It will be apparent from all these diagrams that the values at the 80° blade position are higher than at the 2800 blade position. This is because an assumed inclined inflow was employed in all the calculations (see Table i).

In the case of ship i there is extensive agreement between

the model and estimated full-scale results, although the increase and decrease about the 12 o'clock position is somewhat steeper

for the estimated full-scale wake field.

In the case of ship 2 there are large differences between the

calculated values for the two scales. If it is assumed that

the full-scale wake field of ship 2 has been correctly calculated

it is to be expected that there will be major differences be-tween the cavitation behaviour on the full scale and that

ob-tamed -From model scale investigations. As will be seen from Figs. 11 and 12, in the estimated full scale case the increase

and decrease takes place over a very short range of blade

positions, from 3400 to 20°, while on the model scale this

change occupies an angular rotation of the propeller that is almost three times as high. Although the change in loading on the propeller blade for the estimated full-scale wake field

takes place over a very small part of the propeller rotation,

in a region that is closest to the shell plating, a comparison

with Figs. 9 and 10 for ship 1 will not by itself provide an

explanation for the major pressure variations that occurred

only on ship 2.

In the case o-F ship 3, Figs.13 and 14 show a good correlation for blade positions adjacent to the 12 o'clock position.

Atme distance from this, to both port and starboard, there are however appreciable differences. So far as the question

of pressure -Fluctuations is concerned, these differences are not of any great importance, since they relate to blade

positions that are remote from the shell plating.On the other

hand the differences cannot be ignored if the cavitation be-haviour is being estimated or investigated.

In the Author's opinion, a comparison of the variations in the values of the angle of attack as shown in Figs. 9 to 14

demonstrates clearly that the propeller for ship 2 was designed

with reduced loading of the blade tips.

In addition, from a comparison of all these diagrams, it is

apparent that the efforts that are being made to obtain a

knowledge of the wake field on the full scale are very important.

Figs. 15 to 17 show a comparison of the radial stress distribution for all three ships and their wake fields to both scales.

In the case of ship 1 there is again good agreement for the

average value and for the double amplitude of the variation, while in the case o-F ships 2 and 3 there is agreement for the

10

-average values, but differences in the double amplitudes. At the design stage this result is, however, not of such

critical importance as that for the local lift coefficients

and local angles of attack.

Figs. 15 to 17 also show for all three ships the results o-F

the thrust and torque variations on the propeller and the

bearing -Force and bearing moment variations. Fig. 18 illustrates the mordinate system employed, and Fig. 19 gives the results o-F the thrust eccentricity.

As B<pected, good agreement is obtained for ship 1, which is also reflected in the KX and KYZ values proposed by Schwanecke. Here the amended de-Finition proposed by Kerlen /5/

is used for these factors, all forces being made dimensionless by the use of the average thrust, and all moments by the use

of the average torque. Schwanecke, on the other hand, does not

ue the average torque, but a moment consisting of the average

thrust multiplied by 0.15 0. This di-F-Ference explains, -For instance, why the K values according to Schwanecke's de-Finition would be larger -For ships 1 and 2, and smaller -For ship 3.

This, however, is o-F no importance for the comparison that is

being made here.

The agreement for ship 2 may also be regarded as good; only

in the case o-F the LQY component is the value in the estimated

full-scale wake field appreciably higher. There is agreement

therefore only in the KX values.

There is agreement for three of the components in the case

of ship 3. The values of the components FFX, LX, and QY are

higher in the estimated -Full-scale wake field. From these results the great importance of a knowledge o-F the full-scale wake field -For the propeller designer once again becomes

5. INVESTIGATION OF THE SYSTEMATIC VARIATION OF A WAKE FIELD Starting with the wake field shown in Fig. 1, a simplified wake field was produced (Fig. 20), and this was varied in three t'ays. The simplified wake field shown in Fig. 20 is referred to below as the reference wake field or the 80°

reference type. In it the velocity change commences at the 60° position.

The variations on this reference wake field were performed as shown in Fig. 21. The change in the velocities about the

o o

12 o clock position then commence at 20 or 40 , so that the

wake region becomes narrower, or at 800 and 1000, so that the

wake region becomes wider than for the reference field. In the case of wake fields Type A and B the average values

are maintained constant on each of the five radii. To enable

this to be achieved with changes in the wake peak, the local values at the 0 position were varied in Type A and at the

180° position in Type B. In the case of the Type C wake field,

on the other hand, the local values were maintained constant

at the O and 1800 position here the average values on the individual radii were therefore altered.

This investigation was commenced since naval architects frequently wish to know what form a wake field should take in order to

produce satisfactory results as regards propulsion, cavitation,

vibration, and pressureson the shell plating. An investigation

o-F this nature can certainly answer these questions only in part. The only reliable method of obtaining in4'ormation on the

cavi-tation behaviour is to perform systematic cavicavi-tation tests, as

is confirmed by the calculated values for the lift coefficients and angles of attack OC° reproduced below.

Mention should be made of the following: If the equations for the design of wake-adapted propellers, as given by Lerbs or

12

-given by Brehme and Nleyne /6/), were to be formally applied,

the radial pitch distribution would be the same for the Type A and B wake fields for all versions from 200 to 1000, since the average values at the corresponding radial points are

the same.

Fig. 22 shows the wake field for the 60° reference type. The ratio v/v _{is shown. Figs. 23 to 28 then show for}

corn-m

parison the "constructed" wake fields for Types A, B, and C.

A° version

was not produced for the Type A series, since

this would have negative velocity values at the 0 position.

As in Section 5 above, harmonic analyses were performed for

all the wake fields. Fig. 29 shows the first 6 harmonic

components for the A wake family, and Fig. 30 those for the

B family. No new information was derived from the investigations

on the Type C series.

From Figs. 29 and 30 it will be seen that the harmonic component A3 becomes zero for a field type larger than 1000 (probably

120 ), A becomes zero for a field type between 80 and 100 (probably 90°), A5 for a field type between 60° and 80° (probably 72°), and A6 for the field type 60°. This result

gives an indication as to the number of blades that should be

selected for a given wake field in order to keep the level

of excitations low. These results are independent of the

magnitude of the harmonic components, which are very different

in the two fields o-F Type A and B.

From an investigation of the average velocity value _ó(x),

as defined in Section 3, (see Fig. 31) it can be concluded that,

as compared with the 60° roference type, the 40° Type A, the

80° Type B, and the 1000 Type B are less satisfactory as regards homogeniety of inflow.

Calculations of the lift coefficients and the angles o-F

13

-largest maximum values and the steepest variation gradients

occur for the 400 type, and the lowest values for' the 1000 type.

In the case of the Type B family the maximum values of and

y0

all have the same magnitude, the differences being in the

gradients (see Figs. 32 to 39).

The above investigations were based on ship i and were performed

using the six-bladed propeller of ship 1. The cavitation results

for the 600 reference type are therefore in effect known.

Since no systematic tests have been undertaken it is difficult to comment. It may, however, be permissible to conclude that

the 80° Type A, and also the 80° Type B and 100° Type B would be

likely to exhibit relatively better cavitation behaviour. Fig. 40 shows the results of a calculation of the stresses at

0.3 R on the pressure side. The values of the ratio of the double amplitude of the stress to the average value of the stress, or of the stress maximum to the average value, show

o o

that the stress fluctuations in the 40 Type A, and the 80

Type B and the 100° Type B are higher than in the 60° reference

type.

Figs. 41 to 43 show the results of calculations of the shaft

forces and moments (average values in Fie. 41, double amplitudes

in Fig. 42). Fig 43 shows the thrust eccentricity and the

comparative values KX and KYZ. Since, as mentioned above, the

investigation was performed using the six-bladed propeller of

ship i for all types of wake, the optimum values were obtained,

as was to be expected, with the 600 reference type; this is particularly obvious with the KX and KYZ values.

This indicates that the "correct" choice of the number of blades

is of decisive importance as regards the adaptation o-F the

propeller to the wake and the excitations. This is very apparent

- 14 *

6. REFERENCES

/1/ Blaurock, J., Collatz, G.., Heinzel, S. and Helm, G.: Untersuchungen verschiedener Zwei schraubenanordnungen für Schiffe großer V6lligkeit. FUS Report 52/75.

/2/ Nleyne, K.: Statische und dynamische Beanspruchung

von Schi-Ffspropeller-Flügeln. STG, 1970.

/3/ Morgan, W.B., Silovic, V., and Denny, S.B. : Propeller Lifting Surface Corrections. SNAME, 1968..

/4/ Schwanecke, H.: Ober den EnergieVerlust eines

Schif-Fspropellers bei Längs- und Drehschwingungen

und bei Flügel-Biegeschwingungen. Schiff und Hafen, 1968.

/5/ Kerlen, H. : Über propellererregte Vibrationen auf

Schiffen. Hansa, 1970.

/6/ Brehme, H. und Meyne, K. : Zum Entwurf von Propellern hoher Leistung. STG, 1974.

Table 1:

_{Hain dota}

o

_z

_(PIB)m

_AE/A0

obque flow

Propell@r br

mm

-

-

-Ship

1 7000

tZ35

Q.5Q

.'T9

Ship 2

6100 5 0.931

0.80

1.2.114 10

Ship 3

7h00

O.26

0.L0

14.V70 10°

L

6

T

C8 P RPM m

-

kn

Sp 1

19L15 30,5 9,6 .522 25.3

T

35oo

9&5

Shtp 2

30,5 _{9,IL 0.6313} 25.3 T 3?zoo 12.O

Tu1e 2:

Mean wave figures

ol a'l woke fields

Wefectjve

ship

i

Q.11 'J1L45

ship

2 0333

ShIp 3

0.616 1+0° - TYPE 4 0.193 GO° - Btsts TYPE o. 193 800 - TYPE 4 0. 193 100° - TYPE A a. 13

20° - TYPE B

0.193 1Q°-- TYPE B 0.193 60° - BASISTYPE 0. 193 Ô0° - TYPE B ₀₁₉₃

100° TYPE

0.193 200_ TYPE C _0.135

LO° T''PE C

U.11f

60° BASSTYPE

0.193

80° TYPE C

0.Z21

i 80°

MODEL SCSLE

H9.1:

WkefieId of ship i

(Contoner ship)

00 1800

ESTtMATED FULL SCME

0.9

F1

00 06 I i _0.7

0.8-0.k Fig.Z:

WakefieId of shp2

(Contner ship)

0.9 0.5 0.6 0.7 0° 0.5 ₆ 07 I I 0.8 0.9 Fiq. 2 00 18 U

i

Uo

o.

Ft3

900

I 8U 18û°

M OD EL S CALE _{ESTMA1ED FULL SCALE}

F(: Wukf(e1

of ship 3

a O

ai

û. as a

ai

UO5

A3

s

A2

A14

A6

c7

/

ESTIMATED FULL SCE

-

MODEL St1E

02 0.1+ _{0.6 0} 1.0 01 0.L 0.6 0.8 1.0

x= nR

û, z Ui û.1

-0.05 U OE05

A3

Fig. 5

ESTI MATED FULL SCME MODEL SC1E

to

0.6 0.6

01 0.L 0.6 0. 1.0

ûî

x= nR

-0.1 U.0 O

A

₅ 1.0 01 FSTlt1PTED FULISCALE

-

NIODELSCM.E oil. 0.6 0.8

Fíq.6:

First six hrmonc components of both

_{wQkefields (ship 3)}

f .0 0.3 0.2

-0.1

-o 0.1

0.05-û

0.15

0.10

0.05

-1

X-

r/R

-t

I I I I i I I 0.2 0.3 0. 0.5 0. 0.7 0.8 0.9 1.0

0.20

-ESflMATED FULl SCtLE

MODEL SCPLE

-0.3 0.L 0.5 0.6 0.7 0.8 0.9 1.0

fl7:

_{Average d.viaticn from overaqeveIocitatthe radU of ship '1 Qnd2}

Fig.7 0.20 0.15

(x)

0.10

I

0.05

/

_{x= r/R}

0.30 0.zs 0.20 0.15 0.10 0.05 o

X= nR

I _I t t U.Z 0.3 O. 0.5 0.6 0'7 0.ß 0.9 1.0

Fi9. ô:

Averoge deviutionfrorn verae ve1ocit

Githerudiiof ship3

Fg.S

ESTMTED FUll SCE

0.5

0.140.3

-0.7

-0.1

-I o n 6 5 (f 3 z 80° 300° 370° 31400

blade

pas1ton j r i i LO° _{60° 80°} r i 31300 3200 _3L0° 20° LIJo _{60° 80°}

Fq. 9

UIt coefficients an anqes of attack ¡n mod et wakefield

(ship 1)

Q6R 0.7R 0.8R OIR 0.9 R 0.8 R 0.7 R 0.6 R

0.5

0.k0.3

0.2

-0.1

-O 280° 300° 3200 blade position 60° 80°

-i-.-3200 _3L0°

r

20° tfQ° 60°

Fg.1U.

Li ft coefli cents and ang\es of attock tn es\imaed full scale

waRefiet

(thipi)

F.1O

0.9R 0.9 R 0.6 R 0.7 R 0.6 R

2800

6j

o 300° 320° 3 klJ blade position 00 blode position 20° LO° 60° Fg.11 Û.8R 0.9R 800 i I I i f 280° 3QQ0 320° 3L0° 28° LO° 60° 800

1t

Lilt coefficients on anes olttock in modes wakefield

(ship 2)

0.6 R 0.9 R 0.7 R o.s R 5 3

i

U

0.5 0.3

0.2-0.1

-O 5 k 3 2

I

bi ode position 28Û 300° 320° 3L0° o° 20° LO° 600 800 6 blade position

-

I I 2800 3000 _370°

_30°

70

Qo 60 800

F it?:

1111 coefficients und ungles of attQck in esllmQted lull scue

wokfie1d (ship 2)

U6R 0.7 R 0.8 R 0,9R 8.9 R 8.8 R O.7R 0.6 R

0.3

0.1

-5 z

I

a Fig. 13 0.6 R 0.7 R bode position I i

'J

'I-G-)

C

C

_{bIoe position}

Z80° 3000 3200 3O°

Fig.:

Lift coefficients on

n1es of attack in ethmuted full scale

wake1iel

(st-ip 3)

0.9 R O. R O.IR 0.6R ZU° LU° 60° 800 3000 3200 _3L0° U°

6-O 5 L 3 z

zû

0(8 bTad posikion 300° 3?O° LU° 60° blade posilion 2O0 _300° 370° 3L0° 70° LU° O°

F\giL:

Lift coethcents and angles olcitack in estimated full scale

Wakefield (ship3)

07g

09R

0.9 R 0.6 R O. R

Radìul

siress

tsribuÌion a lace side

_tkp/cr2]

)

hode wakefield:

b)

siirnoed fu scolo wakeield

Propeller exciled force and monen fluctuolions

EsrnaÌed fu1 scale waefie1d <X 0.05; KYZO.17

flgi5:

Calculated results for shtp I

Ft g. 15 Mean 337 312 283 2L5 705 IGL 111f Maximum 521, 1f93 L55 LOO 3L7 Z7 19 Minimum 273 253 229

17

IGL t30 Mean 3LL 319 290 751 710 117 5L1 508 ,9 t

32

Zi

Maximum Minimum 283 63 23 706 172

FFX

FFY

FFZ

QQX

QQY

OQ.Z

to to mö mfü Mean 168.39

-

1+.GL 257.7L 67.73 2120 Maximum 17753

16?6

-

g.8l

-

12.83 5.29 260.93 7ß.S 7587 Minimum L21 53.65 57.70 Mean _68.08

-

13.23 L83 257.71 66.79 77.69 2752 79.36

Maxi mum 170.85

-

11.70 5.62 59.Ik

Minimum 16[+.I

-

IL'30 3.95 755.33 57.SB IG.20

Model wake1ie:

1ÇX=û.09, KYZ.15

Padial stress disinbuf ion at lace side

{kp/cmzJ

)

Hoe1 wokete1d;

Propelter exciled force

rìdmornentftucuatl0nS

b)

Eslimaed

luH

scale wakefì&:

b)

Esimate full

scale wokef&d:

KXO.07, YZÙ.6l+

hg 16:

Colculed

_{resulls for}

_{htp 2}

Hg.16 Mean 31 276 Z40 19'7 ₁₅₉

Mairnum

t31

36

3L7 Z95 750 220 168 Mnmurrì ZL ZIO

i0

1L7 118 gg Mean 377 291

79

718 181 ISS 115 Maximum 635 L80 L31 370 315 21

tiZ

Mnrnum 237 16t 1317 117 85

FFX

FFY

FFZ

QQX

QQY

QOZ

to to to mio mo mo Mean 159.60 - 3.77 1.80 162.56 79.35 12.72 Moxmum 162.33 - 3.3 7.27 16.53 32.80 lLf.03

Mnmum

157.LO +Û8 123 60.89 75.36 Mean 156.80 - k.SO 3.59 62G7 Z9.L1 18.6

Mamum

162.62 - 0.21 5.3 163.37 62.9I 30.29 Minimum 15501 - 9.56 6 160.27

-

22

)

1ode wakef'

ÇÍ3Q6;

KYZ:Q.1O

Radial stress distribution atfnce side

kp/cmz]

Mode wakefield:

Estimated fu scale Wa.<e1&d:

Propeller excited torce and

mornen 1Ìucuations

)

Model wakeield

Fíg.17:

_{CalcuIGted resu1s for ship 3}

KX0.16; tKYZ 0.20

)

Ethmaed full

cle wake1ied: KXC.30;KYZ:U.1+3

Fig. 17 Nleart L50 LOE 3Cl 322 263 1914 119 Maximum 519 503 k56 L18 351 266 171 Minimum 323 7.82 2L1 206 163 118 71 Mean L?6 380 331+ 297 21+6

18

121 Maximum 683 67.3 561 507 1+21 17 201 Minimum 290 7.58 7.27 '199 163 126 82

FFX

FFY

FFZ

QQX QY QQZ

to

to

to mio mto mio

Mean 200.00

-

Oi+5 ICL.93 31.83 6i8

Maxrnum

211.91 - 0.60 0.75 1'10.29 39.11 17.1+9 Mintmum 191.01 -1.91

-0.03

160.75 ZZ.1

-

1.57 Mean 199.90

-.3ß

0.1+6 1GL.88 10332 8.89 Maximum 7.22.11+ -6.31+ 1.26 175.28 135.93 1526

Minimum

8L0

-995

-0.21 157.21 1.09 1+19 U.3R 0.LR. 0.5 R O.6R

08R

z

GZ

QZ

FZ

EF Z

Fig. IB:

CoordinQte system-denitions ollorces Qnd

moments on propeller

(right-bonded propeller)

FEY

/Y

UQY Fg. 1

0.7 R 0.15 R aiR

-Ship 1 C,,

w

$ 0.05 R

ey

thrust eccenÌrictty

N G)

ESTIMATED FU1 SCALE

MODEL SCALE

Ship 2

Ship 3

ey

I

q;

Fig l:

Comparison of colculated results olthtusteccen1ricit

for oil 3thips

Fig1

tú

-0.8

-0.6

01

-Fg.:

Basis WoIefie1d

7700 ISO 900 Fig. 20 1.OR O. R 0.6 R O.k R 02 R

00 _{20° LO°} 600 800 1000 _{IZO° iLO° 160°}

V

Vm 1.0 0.8

V

m 1

:.:

O

WAKEFIELD TYPE A

t t I

WAKEflELD TYPE B

1.0 x=02 R

WAKE flELD T'T'PE C

x=0.2 R t t I I x. 0.2k I f I I I 0° ZOD _{10° 60° 80° 100° 120° ILO° 160°} 1B0

Fi.?1:

_{Modication ol wake field}

at each radus are: I zir L;-

vfl

conSan V (10°) constant Vm V _(0°)

₌

_vrabet Vm

a each radius x are:

d.q constant Vm V _{(10°) vartabet} Vm V _(o°) c,onstck Vm

at each radius x are:

ir

zirJ - ct

vartabel o Vm V ₍₁₈₀₀₎ constant Vm V (fo) constant Vm 0 180° 90° too 0.8 V 0.6 0ì4 Ui o

18û°

Fg??

BQss wake 1ie1

WAKE FIELD

60° -BSIS11PE

00

OE2 g3 g

5

F g .23

Fg.23:

Woke fe1d L0°-Tpe A

90°

WAKE FIELD

L4O°,.... TYPEA

U0

180

WAKE FIELD

800

-

_TYPEA

Fg.7L

Woke field

BU°- ond 1UO°-Tpe A

r

BU°

WAKE FIELD

1000 -TYPEA

Fig 2L o.

00 i

Sj

o« 1800

WAKE FIELD

200

-

_TYPES

FiS.

Wake f ied

ûnd LU°- Tpe B

i80

WALK E FIELD

LO° -TYPEB

Fiq5

9C°

1BÚ°

WAKE FIELD

80°- TYPEB

Ffgi:

Wake 1ied

tJ°- Qnd 100°-Type B

i U°

15

WAKE flELD

1800

WM<E FIELD

200 TYPC

Fig Z7:

Wake field

?U°- und LO°-Tjpe C

1800

WAKE FiEL1

LO°

-

TYPEC

Ftq27

U0 i ßO° Fíq.ZB:

Wake fe1

8U°-

iUU°-TpeC

WAKE FIELD

BO° - TYPE C

i8O

WAKE FIELD

1000

-

_{TYPE C}

Fg 1j. qU O

1.3

02

-U .1 û 0.1

- 1105-û 01 0.05 -A1

43

0.2 C.L 0.6 0.8

X==

r/

0o 80. 1000 0e

42

116 0.8

Fig. 2:

_{Fftst sx hQtmonic components O we e1d fQmtJ type A}

Fia. 79 1.0 L0 60* B0 00. 1f0* 60' )0o 1000 o0 loo0 00

-02

-0.1 O 01

-UI

-

0.05-A1 A3

A5

100° 80

_A

600 L0 s l0. 600 ao 80° 100 20 0. _1000 no ut,

.

so,-1.0 02

A

'0' 20' 600 80' 2

Fig.30:

_{First six hoímonc components owokeie1}

_furn1

_type

Fi. 0

1000 +0. 200 00 .1o. 60° 0.L OE6 0.8 10 0.05 O U 02 0.6 0.8

x==

r/

0.05

-3.0

3.15

-6(x)

Fiq.31: PNErQge vtoìon from average ve1oc

atthe radii of

the three wKe field Ìpes A, B, C

x

F..3l

WA<EFIEW TYPE B

WAFIELD TYPE C

I I I 01 0. 0.5 0.6 0.7 O.B 0.9 1.0 600 o0 i 000

WAKEFIELD TYPE A

100 80 600 20° i 000 §0° 60° LO° 230 ojo 0.05

-3.0 0.15 -013 010 3.05 0.0

g.? -0.6

-0.5

-Oil. 10 0.3

-01 01

-O I 2800 3000 3200 _3O°

o

Q G.) C Q

r'

- -

_320° 3000 Z 800 3l 0°

blade positon

Fig. 3Z

Fg 3Z:

Lift coefficients and ang'es

of attacK in wuke field

20°

LO0 TYPE t\

L0 600 800 LO° o 800 0.6 R 0.7R 0.8R 0.9 R 0.9 R 0.8 R 0.7 R 0.6 R 7 6 3

0.5 0.14. 0.3 0.2 0.1 6 2 0° 2800 300 320° 3200 3L0°

bInde position

Fig. 33

H.33

_{Lift coefficients ad angles}

of attack in wake fe1d

600 BASIS TYPE 200 I I f tUo LU° 60° 600 BO° 800 0.6 R 0.7R 0.8R 0.9 R 0.9 R U.S R 0.7 R 0.6 P.

0.5

-

0.3-

01-o-t

280° 3000 3200 3L0°

blade posfon

0° blade osttion Fq.3L

Fiq.3(4:

Lifl coefficients and ang'es

of atthck in wake fe1

TYPE A

£0 0.6 R 0.7 R 0.8 R o.g R 0.9 R

o p

0.7R 0.6 R 3000 3200 ₃₍₄₀ 00 200 LU° 600 80°

0.5

780° 3000 320°

30°

6 s 3 U blode pcsikion U0 blode posilion Fi g.

Ñg.35:

_{L1k coe11cìenis and angles}

ol uttock in woke field

1O° TYPE A

200 _LO° 60° 80 O.6R 0.7 R 0eR 0.9 R 0.9 R 0.8 R 0.6 R 200 O° 5fl0 2800 3000 _{320° 3L0°} 0°

U.S -Qtf

0.3

-01

0.1 o i U 2800

6-I I I 300° 320° 3L0°

bde position

F g. 3 Fíg.36:

_{Lift coefficìen'is and ang\es}

of attack n woke fieÌ.

200 TYPE B

J I I 20° LU° 600 0.SR 0.7 R 0.8 R .q R 0. R 0.8 R 0.7 R 0.6 R s 3 o B 100 _LO° 300° 320° 3L0° 2800 0°

oH

U.3

0.2

0.1

-U 6 14 3 7 780°

20°

3000 3730 31430 blade positìcn

Fg.37;

UIt coefficients and angles

of attack ¡n wake field

'+0° TYPE B

t I 730 1400 530 300° 320° 3140° n 70° 140° 60° 0.6 R 0.'1 R 0.8 R 0.g R 0. R 0.8 0.7 R 0.6 R

-j

L)

3L0°

bio de position

Fig.3

Fig.38:

Lift caefficìers ond angles

of attack n wa<e fe1d

300 1YPE

LO° _80° o.6R 0.7 R

0R

O.9R o.g 0.7 R 0.6 R 2800 3000 _{3 0°} 34O° 00 20° 60° OU o 300° 320°

O L)

a

O) 300° 3?tJ0 280° 300° 3200 3l4f 3L0°

blaóe posit ion

Fig. 39

F39: tjft coefficients an

angles

of attack inwake field

1OQ° TYPE B 200 _LU° 60° 80° 0.6 R 0.7 R U.S R 60° 0.9 R 0.9 R 0.8 R 0.7 R 0.6 R 800

Fi9.E0:

Stresses at 03R foce side

ratio doub'e arnp1itud/meon

stress and mxtrnum stress/meun

stTess

- caldutaed ¡n the

wake fietd lamihes A,,C

for the six-b1adpropeUer

ship I

ZOO-TYP E 'N

\\

'-

;-_

0

(6m-6mean mx Ornecn

N

Fq.LO

N

EF7ELO

_C

A1 I I LU°- 60°- 80°.-

100°-TYPE BS1TYPE TYPE TYPE

1.0-

0.9-

0.8-0.7

-

0.6-0.5

-0.L 0.3

-02

-0.1

-o

WAKEFiELD TYPE A

WAKEFiELD TYPE B

WAKEFIELD TYPE C

Fg.1'.

Suft forces und rnomens

(mean

values)

n the wake field famiUes A, B,C for

thsix-badea propeller

_{of srp1}

cnku1od

FigLi

TYPE

FFX

FFY

FFZ

_ÜX

_QQY

_QZ

to to to mto mto rnto

20° LU° _168.5

_-122

.5 757.9 75.0 20.L 600 _{1G7.3 -12.9}

_Li

_{757.L 72.3 70.0} 80° 168.1 12.8 3.9 _257.9 68.8 19.3 100° 168.0 -11.9 .7 757.8 62.8 18.6 200 _168.5

-3. 253.2 2L 17.8 LO° 168.2

- 8.L

.1 257.3 L8.L 18.8 600 _167.8

-

_12.9 L? 257.L 72.3 20.0 800 _{168.L - 17.7 258.1 97.1} 20,7 1000 _{1G8.6 -77.7} 3.9 258.k 121.3 _20.8 0°

_{- 5.8}

_{.5 258.5 33.0 2L.Z} LO° 168. 9.8 L.9 257.9 55.6 71.9 60° _16,8

-

12,9 L? 757. 77.3 70.0 80° 168.3 -15.1 3.L 258.0 _{8L1 17.7} 1000 _{168.3 -16.} 2.7 258.0 90.0 152

WAKEFIELD TYPE A

WAKEFiELD T'IPE B

WAKEFIELD TYPE C

Fíq. L:

_{Shalt forces pnd nornens(doube ampi itudes)}

-

_cucu1oted

ìnthewokefeIdfomWes 4,B,C ftr

th si-bWded propeller o shp1

Fig. L2

TYPE ¡FFX

FFY

AFFZ

QX MIQY AQZ

to to to into rnto nito

10° 140°

iL

5.33 6.37 ₃₅₇₇ 630 _{1.L5 0.58 0.72 .L6} 14.214 _1.09 80° .80 0.GL 1.21 L.73 6.05 5.79 1000 _{2.93 1.014} 1.32 2.814 6.71 ₇₁₉ 70° 21.53 533 1,9? 20.16 55.12 _11.83 LO° 10.38 3.98 3.66 7.79 31.56 _23.06 60° 1.14s 0.58 0.72 LL6 L?14 1.09 80° 6.142 0.65 1.97 6.0e v.85 .67 1000 _{5.19 1.70 2.85} 14.58 12.15 114.90 200 _{28.71 11.09 2,57} 26.86 73.09 15.75 14Qo 11 .87 kS? L.26 8.82 36.30 26.56 60° 1kB 0.58 0.72 L146 14214

f09

800 _{5.58 0.59 1.66 5.23 6.78 7.145} 100° 1406 1.28 1.96 3.56 920 10.1414

Fíq.3;

Trust

ccen1ricìÌIs ond K-v1ues

_co1cuute

in The wQke field families A, B,C for

the six-bladedpropeer fship1

F4L3

Wukeie1d type

Thrust eccenriciti

er/R

ez/R 0.17 38 0.03 03 005 0.03 0.07 _ _{TYPE A}

_0.31

_{O 03L O.12}

60-

STYPE

3.i2

0.Q3

O11

80°- TYPE A

U I0

0.032 0.115 100°- TYPE A 0.110 0.031 0.105 0.21 0.32 0.09 0.26 0.03 0.03 0.05 0.US 0.06

013

- TYPE B 0.050 0.030 U.BkU

O- BS1STYPE

0087 0.03? 0.081 600 _{TYPE B 0.126} 03+ 0.121 300

_-

_{TYPE B 0.167 0.035 0.163} 100°_ TYPE B 0106 0.035 0.703 0.27 0.L2 0.10 0.30 0.03 0.03 0.05 0.07 0.0k 0.10 20°

-

TYPE C 0.066 0.OLO 0.052

LU°

-

SiS TYPE 0.100 0.037 0.093 60°- TYPE C 0.126 U.03L 0.121

0° TYPE C Q.ILL 0.030

100°- TYPE C 0.153 0.025 0.151

K-vouS