Computational Analysis of Added Resistance in Short …€¦ · Computational Analysis of Added Resistance in Short Waves ... Kim and Kim (2011): Rankine panel method in time domain,

Computational Analysis of Added

Resistance in Short Waves

2013 International Research Exchange Meeting of Ship and Ocean Engineering in Osaka

20-21 December, Osaka, Japan

Yonghwan Kim, Kyung-Kyu Yang and Min-Guk Seo

Seoul National University

Department of Naval Architecture & Ocean Engineering

Background

2

Need for analysis of added resistance in short wave due to increase of

ship length

Investigate the effect of different bow shape to added resistance

Energy Efficiency Design Index (EEDI) Restrict greenhouse gas emissions

Added Resistance

Strip RPM CFD

Experiment Numerical Methods

State of the Art

3

Experiments Journee (1992): Wigley hull

Fujii and Takahashi (1975), Nakamura and Naito (1977): S175 containership

Kuroda et al. (2012): Different bow shapes above the waterline

Sadat-Hosseini et al. (2013): KVLCC2

Kashiwagi (2013): Modified Wigley hull, Unsteady wave analysis

Potential Flow Maruo (1960), Newman (1967), Salvesen(1978), Faltinsen et al. (1980)

Joncquez et al. (2008): Rankine panel method in time domain

Kashiwagi et al. (2009): Enhanced unified theory, correction in short waves

Kim and Kim (2011): Rankine panel method in time domain, irregular waves

Seo et al. (2013): Comparative study for computation methods

CFD – Added Resistance Orihara and Miyata (2003): RANS, FVM, overlapping grid

Hu and Kashiwagi (2007): CIP, Cartesian grid, immersed boundary

Visonneau et al., (2010): Unstructured hexahedral grid, mesh deformation

Sadat-Hosseini et al. (2013): RANS, overset, block structured, Level-set

Rankine Panel Method

4

( )T R x

2 0 in fluid domain Governing Equation

2

2( ) ( ) on 0d d

d d IU U zt z z

1( ) ( ) on 0

2

dd d IU g U U z

t t

6

1

onjd I

j j j B

j

n m Sn t n

1 2 3

4 5 6

( , , ) ( )( )

( , , ) ( )( ( ))

m m m n U

m m m n x U

Kinematic F.S.B.C.

Dynamic F.S.B.C.

Body B.C.

x

y

z

U

o

,A

FS

BS

( , , )z x y t Equation of Motion

Linearized Boundary Value Problem

FRes : Restoring force

FF.K. : Froude-Krylov force

FH.D. : Hydrodynamic force

. . . . .[ ]{ } { } { } { } ( , 1,2,...,6)jk k H D j F K j Res jM F F F k j

Added Resistance (RPM)

5

2

2 3 4 5 3 4 5 1

3 4 5

0 2

3 4 5

1 1( ) ( ( ))

2 2

1( ( ))

2

1

2

( )

B B

WL WL

WL

I d I d

S S

I d

F g y x ndL U y x n dLx

U y x ndLx

gz n ds nds

g y xt

1

2 1

1 1

2 2

B

B

B B

I d

I d

S

I d I d

I d

S

S S

U n dsx

U ndst t

U n ds U n dsx x

1 2,Rn n n Hn

2 2

5 6

2 2

4 5 4 6

2 2

4 6 5 6 4 5

( ) 0 01

2 ( ) 02

2 2 ( )

H

Near-field Method,

Direct Pressure Integration Method (Kim & Kim, 2011)

Cartesian-Grid Method

Fluid Flow Solver FVM + Fractional step

MC limiter

Cartesian grid

Free surface capturing

(THINC / WLIC)

Solid Body Treatment Triangular surface mesh → Volume fraction

Level-set + Angle weighted pseudo-normal

Immersed boundary method

6

*

** *

1

1 **1

1

1 **

1

0

1

1

1 1

nn n

bn

nn

n

n

n

u uu u n dS

t

u uf dV

t

u up ndS

t

p ndS u ndSt

1

1

1/2

0

1 tanh2

i

i

i

ut

x xF x

x

1/2 1/2

1max 0,min 2 , ,2

2

/ / /i i

rr r

r q x q x

Added Resistance (CFD)

7

Time (sec)

Fx

(N)

5 10 15-2

0

2

4

6

8

10

12

Time (sec)

Fx

(N)

5 10 15 20 25 30 350

1

2

3

4

5

6

<Wigley III, Fn=0.3 >

R_calm

R_wave

R_added R_wave R_calm

Added Resistance in Short Wave

8

2 2

2

1

2

6 0 0

1 2sin ( ) 1 cos cos( )

2

sin

cos

cos sin

IL

UF g ndL

g

n

n

n x y

2

2

2 2

2 2 2 2

1 1

2 2 2 2 2

1 1 1

1(1 ) ( )

2

1( ) sin ( )sin sin ( )sin

Fujji & Takahashi (1975) NMRI (Tsujimoto et al. (2008), Kuroda et al. (2008))

( ) ( )

( ) ( ) (

d U I f

fI II

ed d

e

F g BB

B dl dlB

I kd I k d

I kd K kd I k

2

2

1

,) ( )

1 1 5 1 1 , max[10.0, 310 ( ) 68]

ee

e

U n U U n U f

kd K k d g

F C F C B

Faltinsen et al. (1980)

Fujii & Takahashi (1975),

NMRI’s method (Tsujimoto et al. (2008), Kuroda et al. (2008))

Cross-section equal to the waterplane area

Local steady flow velocity

Simulation Conditions

9

<Panel Model for Rankine Panel Method> <Grid Distribution for Cartesian Grid Method>

<Triangle Surface Meshes for

S175 Containership and KVLCC2>

Model L(m) B(m) D(m) CB

Series60 100.0 14.29 5.72 0.7

100.0 15.39 6.15 0.8

S175 175.0 25.4 9.5 0.561

KVLCC2 320.0 58.0 20.8 0.8098

Motion Response (S175 Containership)

10

<Vertical Motion Responses of S175, Fn=0.25>

<Heave> <Pitch>

(L/g)1/2

3/A

1 1.5 2 2.5 3 3.5 4

0

0.5

1

1.5

2

2.5

Exp. (H/=1/120, Fonseca, 2004)

Exp. (H/=1/40, Fonseca, 2004)

Rankine panel method

Cartesian grid method (H/=1/40)

(L/g)1/2

5/k

A1 1.5 2 2.5 3 3.5 4

0

0.5

1

1.5

2

2.5

Exp. (H/=1/120, Fonseca, 2004)

Exp. (H/=1/40, Fonseca, 2004)



Motion Response (KVLCC2)

11

< Vertical Motion Responses of KVLCC2, Fn=0.142>

<Heave> <Pitch>

(L/g)1/2

3/A

1 1.5 2 2.5 3 3.5 4

0

0.4

0.8

1.2

1.6

2

Exp. (H/L=0.01, Lee et al., 2013)



(L/g)1/2

5/k

A1 1.5 2 2.5 3 3.5 4

0

0.4

0.8

1.2

1.6

2

Exp. (H/L=0.01, Lee et al., 2013)



Grid Convergence Test (RPM)

12

L/x

R/

gA

2B

2/L

20 40 60 80 1000

1

2

3

4

5

6

/L = 0.3

/L = 0.5

/A: -2 -1.6 -1.2 -0.8 -0.4 0 0.4 0.8 1.2 1.6 2

< Grid Convergence Test of Added Resistance for KVLCC2, Fn=0.142>

<L/Δx = 37>

<L/Δx = 59>

<L/Δx = 95>

Wave Elevation and Pressure Distribution (RPM)

13

Wave Pressure Wave Pressure

<λ/L=0.4> <λ/L=1.2>

< KVLCC2, Fn=0.142>

Spatial variation of the physical quantities in short wavelength is more severe.

Grid Convergence Test (CFD)

14

L/xbow

R/

gA

2B

2/L

60 120 180 240 3000

1

2

3

4

5

6

/L=0.5

L/xstern

=80

L/xstern

=160

< Grid Convergence Test of Added Resistance for KVLCC2, Fn=0.142>

<L/Δx = 128>

<L/Δx = 160>

<L/Δx = 280>

/L

R/

gA

2B

2/L

0 0.5 1 1.5 2 2.5

0

5

10

15

20

Exp. (Fn=0.207, Strom-Tejsen et al, 1973)



Short wave (Fujii & Takahashi (1975))

Short wave (Faltinsen et al. (1980))

Short wave (NMRI)

Added Resistance (1/4)

15

<Added Resistance of Series 60, CB=0.7, Fn=0.222 >

/L

R/

gA

2B

2/L

0 0.2 0.4 0.6 0.8 1-2

0

2

4

6

8

10

12






Short wave (NMRI)

/L

R/

gA

2B

2/L

0 0.5 1 1.5 2 2.5

0

4

8

12

16






Short wave (NMRI)


16

/L

R/

gA

2B

2/L

0 0.2 0.4 0.6 0.8 1-2

0

2

4

6

8

10

12






Short wave (NMRI)

<Added Resistance of Series 60, CB=0.8, Fn=0.15 >

/L

R/

gA

2B

2/L

0 0.5 1 1.5 2 2.5

0

5

10

15

20

Experiment (Fujii,1975)

Experiment (Nakamura,1977)





Short wave (NMRI)


17

/L

R/

gA

2B

2/L

0 0.2 0.4 0.6 0.8 1-2

0

2

4

6

8

10

12

Experiment (Fujii,1975)

Experiment (Nakamura,1977)





Short wave (NMRI)

<Added Resistance of S175 Containership, Fn=0.2>

/L

R/

gA

2B

2/L

0 0.2 0.4 0.6 0.8 10

2

4

6

8

10

Exp. (H/L=0.01, Lee et al., 2013)

Exp. (H/L=0.015, Lee et al., 2013)


Cartesian grid method (CFD, H/=1/40)



Short wave (NMRI)

/L

R/

gA

2B

2/L

0 0.5 1 1.5 2 2.5

0

3

6

9

12

15

Exp. (H/L=0.01, Lee et al., 2013)

Exp. (H/L=0.015, Lee et al., 2013)


Cartesian grid method (CFD, H/=1/40)



Short wave (NMRI)


18

<Added Resistance of KVLCC2, Fn=0.142>

Wave Contour and Water-Plane

19

<S175 Containership, Fn=0.2> <KVLCC2, Fn=0.142>

<Comparison of Water-Plane Sections>

RPM

CFD

RPM

CFD

Conclusions (1/2)

To predict the reliable added resistance, grid

convergence test should be conducted because the

added resistance is sensitive to the panel size or grid

spacing. Especially, a ship which has blunt bow shape

requires finer grid near the ship bow region.

According to grid convergence test of Rankine panel

method, more panels are required in short wave

condition than in long wave condition. Also, it is

recommended that panels are concentrated on bow

and stern because change of body shape at bow and

stern is much more severe than mid-ship region.

20

Conclusions (2/2)

According to results of added resistance in short wave

region, all computational methods gave good results

when the vessel has blunt body, while only Cartesian

grid method and short wave calculation method

proposed by NMRI provided good results when the

vessel has slender body. This implies that nonlinear

effects which are not included in potential based solver

importantly influence added resistance on a slender

body in short wavelength.

21

22

Thank you all very much!

Q & A

Documents

Computational Analysis of Added Resistance in Short …€¦ · Computational Analysis of Added Resistance in Short Waves ... Kim and Kim (2011): Rankine panel method in time domain,