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National Taiwan Ocean University MSVLAB Department of Harbor and River Engineering. Null-field boundary integral equation approach for hydrodynamic scattering by multiple circular and elliptical cylinders. Jai-Wei Lee and Jeng-Tzong Chen. Date: Jan. 13, 2010 Time: 11:50~12:10 - PowerPoint PPT Presentation
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The 8th Asian Computational Fluid Dynamics Conference Hong Kong, 10-14 January, 2010 2010/01/13 Page 1 Null-field boundary integral equation approach for hydrodynamic scattering by multiple circular and elliptical cylinders Date: Jan. 13, 2010 Time: 11:50~12:10 Place: Lectrue Theater F National Taiwan Ocean University MSVLAB Department of Harbor and River Engineering Jai-Wei Lee and Jeng-Tzong Chen H ong K ong 2010 8
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Page 1: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 1

Null-field boundary integral equation approach for

hydrodynamic scattering by multiple circular and elliptical cylinders

Date: Jan. 13, 2010Time: 11:50~12:10 Place: Lectrue Theater F

National Taiwan Ocean UniversityMSVLABDepartment of Harbor and River Engineering

Jai-Wei Lee and Jeng-Tzong Chen

Hong Kong 2010

8

Page 2: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 2

Outline

• Introduction of NTOU/MSV group• Motivation and problem statement• Method of solution• Illustrative examples• Conclusions

Page 3: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 3

Outline

• Introduction of NTOU/MSV group• Motivation and problem statement• Method of solution• Illustrative examples• Conclusions

Page 4: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 4

The 8th ACFD Conference in HK, 2010.1. 10~14

Keelung

NTOU

HKUST

Page 5: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 5

NTOU/MSV Group members (2010)

1983

1962 1955 19751962 19711959 19761972

1988198719861987198519851978

Page 6: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 6

NTOU/MSV visitors

陳俊賢(J S Chen, UCLA)

程宏達(Alex H.-D. Cheng, USA)

Jeong-Guon Ih (KAIST, Korea)

姚振漢(Yao Z H, China)

( 黃晉 , China)

(M.Tanaka, Japan)

陳清祥(C. S. Chen, USA)

祝家麟(J. L. Zhu, China) 陳 鞏

(USA, Texas A M)

吳鼎文(T. W. Wu, USA)

杜慶華(Q. H. Du,China)

吳漢津(H C Wu, Iowa, USA)

余德浩 中國科學院

美國 中國

日本南韓

Page 7: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 7

Outline

• Introduction of NTOU/MSV group• Motivation and problem statement• Method of solution• Illustrative examples• Conclusions

Page 8: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

2010/01/13 Page 8The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 2010

Introduction of water wave problem(single cylinder)

Analytical solution

circular elliptical MacCamy and Fuchs (1954) Goda and Yoshimura (1972)

Page 9: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

2010/01/13 Page 9The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 2010

Introduction of water wave problem(multiple cylinders)

Analytical solutions are not available

Linton and Evans (1990)Spring and Monkmeyer (1974)

Present methodBoundary type

Meshless method

(Null-field BIEM)

Chatjigeorgio and Mavrakos (2009)

Multipole expansion

74

2b

1

2

3

x

y

incAOR (2009)

Semi-analytical methods

Page 10: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

2010/01/13 Page 10The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 2010

Introduction of water wave problem(multiple cylinders)

To the authors’ best knowledge

OK

Multipole expansion

Multipole expansion ?(Null-field BIEM) OK

Page 11: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 11

Problem statement (3D)

2 ( , ; ) 0, ( , ) ,T z t z D x x

( , ; ) ( ) ( ) ,i tT Tz t u f z e x x

cosh ( )( ) ,

cosh( )k z higAf z

kh

Governing equation

Linearized wave theory and method of separation variables

:h water depth constant

( , )x yx

Page 12: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 12

Reduction to 2D Problem

2 2( ) ( ) 0, ,Tk u D x x

( ) ( ) 0, ,TT

ut B

n

x

x x x

cos( ) sin( )( ) ,ik x yIu e x

( ) ( ) ( ),T I Ru u u x x x

Governing equation

( ) :Iu x

( ) :Ru x

Incident wave field

Radiation field

Boundary condition

2 2( ) ( ) 0, ,Rk u D x x

( ) ( ) 0, ,R It t B x x x

Governing equation

Boundary condition

Page 13: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 13

Outline

• Introduction of NTOU/MSV group• Motivation and problem statement• Method of solution• Illustrative examples• Conclusions

Page 14: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 14

Interior case Exterior case

cDD

Dx

x

x

x

cD

x

Degenerate (separable) formDegenerate (separable) form

2 ( ) ( , ) ( ) ( ) ( , ) ( ) ( ),B B

u T u dB U t dB D x s x s s s x s s x

( ) . . . ( , ) ( ) ( ) . . . ( , ) ( ) ( ),B B

u C PV T u dB R PV U t dB B x s x s s s x s s x

B0 ( , ) ( ) ( ) ( , ) ( ) ( ), c

B BT u dB U t dB D s x s s s x s s x

B

Boundary integral equation and null-field boundary integral equation

(1)0 ( )( , )2

( , )( , )

( )( )

i H krU

UTn

utn

s

s

s x

s xs x

ss

xB B

Page 15: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 15

Degenerate (separable) form of fundamental solution (2D)

1

1

1ln c

1ln c

( , ) lnos

s ,

,

o

m

m

m

m

R mU

R mR

m

m

Rr

R

s x

, , , ,R r s x x s( , )R s

( , ) x

( , ) x

CircleExtension

Ellipse

Page 16: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 16

Degenerate kernels

Modified Mathieu functions of the third kind

(1)0 ( )

( , )2

i H krU

s x r s x

Addition theorem (Morse and Feshbach’s book)

0 1

( , ) ( , )2 ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) , ,( ) ( )

( , )( , ) ( , )2 ( , ) ( , ) ( , )

( ) (

m mm m m m m me o

m mm m

m mm m me o

m m

Se q So qi Se q Je q He q So q Jo q Ho qM q M q

USe q So qi Se q Je q He q

M q M q

s sx s x x s x x s

s sx x s

s x

0 1

( , ) ( , ) ( , ) , ,) m m m

m m

So q Jo q Ho q

x x s x s

Normalized constants

Methods of Theoretical Physics, 1953, p.1421

Analytical study (norm)

Page 17: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 17

Contour plots of the closed-form fundamental solution and the degenerate kernel

0

0

( ) ( )(

, ,

( ) (,

, ,)

)

j j s

j j sj

j

F G

F GU

x

x

sx

xs

s

x

(1)0 ( )

( , )2

i H krU

r

s x

s x

Closed-form fundamental

solution

Degenerate kernel

Abs Re Im

( , ), ( , ) x x s sx s

0 1

( , ) ( , )2 ( , ) (

( , ) ( , )2 ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) , ,( ) ( )

, ) ( ,)

( , )

)( (

m mm m m m m

m mm m me o

m m

me om mm m

Se q So qi Se q Je q He q So q Jo q Ho

Se q So qi Se q Je q He qM q M q

M qU

qM q

s s

x s x x s x x s

s sx x s

s x

0 1

( , ) ( , ) ( , ) , ,) m m m

m m

So q Jo q Ho q

x x s x s

Page 18: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 18

Degenerate kernels

(elliptic coordinates)

(polar coordinates)

Page 19: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 19

Expansions of boundary densities and incident plane wave for circular boundaries

0 1

( ) cos( ) sin( ), ,n nn n

u g n h n B

s ss s

0 1

( ) cos( ) sin( ), ,n nn n

t p n q n B

s ss s

Boundary densities

0

( ) ( ) ( )cos( ( )),nI n n

n

u i J k n

x xxIncident plane wave

Fourier series

Polar coordinates

Page 20: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 20

Expansions of boundary densities and incident plane wave for elliptical boundaries

0 1

( ) ( , ) ( , ), ,n n n nn n

u g Se q h So q B

s ss s

0 1

1( ) ( , ) ( , ) , ,n n n nn n

t p Se q q So q BJ

s ss

s s 2cEigenfunction expansion (Mathieu functions)

0 1

( , ) ( , )( ) 8 ( ) ( , ) ( , ) ( ) ( , ) ( , ) ,

( ) ( )n nn n

I n n n ne on nn n

Se q So qu i Se q Je q i So q Jo q

M q M q

x x x xx

Boundary densities

Incident plane wave

Elliptic coordinates

Page 21: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 21

Keypoint for solving the problem with elliptical boundaries

0 ( , ) ( ) ( ) ( , ) ( ) ( )B BT u dB U t dB s x s s s x s s

( ) s sd s JB d

0 1

( , ) ( , )2 ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ,( ) ( )

( , )( , ) ( , )2 ( , ) ( , ) ( , )

( ) ( )

m mm m m m m me o

m mm m

m mm m me o

m m

Se q So qi Se q Je q He q So q Jo q Ho qM q M q

USe q So qi Se q Je q He q S

M q M q

s ss s s

s ss

s x

0 1

0 1

( , ) ( , ) ( , ) ,

( , ) ( , )2 ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ,( ) ( )

( , )(

1

12

m m mm m

m mm m m m m me o

m mm m

m

o q Jo q Ho q

Se q So qi Se q Je q He q So q Jo q Ho qM q M q

TS qi

J

Je

s

s

s s

s ss s s

s x

0 1

, ) ( , )( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ,( ) ( )

mm m m m m me o

m mm m

So qSe q Je q He q So q Jo q Ho qM q M q

s s

s s s

0 1

( ) ( , ) ( , ), ,n n n nn n

u g Se q h So q B

s ss s

0 1

( ) ( , ) ( , ) , ,1n n n n

n n

t p Se q q So qJ

B

s

s ss s

Orthogonal relations are reserved

Page 22: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 22

Adaptive observer systems and linear algebraic equations

{} { }[ ] [ ] ,U t T u=

Collocation point

Boundary contour integration

( , ) x xx

( , ) x xxdB

dB

x dB

dB

Page 23: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 23

Outline

• Introduction of NTOU/MSV group• Motivation and problem statement• Method of solution• Illustrative examples• Conclusions

Page 24: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 24

Illustrative examples

• Case 1: A single elliptical cylinder

• Case 2: Two parallel identical elliptical cylinders

• Case 3: One circular and one elliptical cylinders

Page 25: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 25

Case 1: A single elliptical cylinder

1 1

1

1

11

101.5

tanh

10

ba

b

h

a

1a1b

1

1

0 1

1

1 1

( , ) ( , )2( ) 4 ( ) ( , ) ( , )( ) ( , )

( , ) ( , )( ) ( , ) ( , ) ,

( ) ( , )

n n nR n ne

n n n

n n nn no

n n n

Se q Je qu i Se q He q

M q He q

So q Jo qi So q Ho q

M q Ho q

x x

x x

x

Page 26: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 26

Number of degree of freedom

Resultant forces of an elliptical cylinder

[3] Au M. C. and Brebbia C. A., “Diffraction of water waves for vertical cylinders using boundary elements”, Applied Mathematical Modelling, Vol. 7, (1983), pp 106-114.

n u ll-f ie ld B IE MB E M

Page 27: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 27

Number of degree of freedom

Resultant forces of an elliptical cylinder

[3] Au M. C. and Brebbia C. A., “Diffraction of water waves for vertical cylinders using boundary elements”, Applied Mathematical Modelling, Vol. 7, (1983), pp 106-114.

n u ll-f ie ld B IE MB E M

Page 28: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 28

Case 2: Two parallel identical elliptical cylinders

1 2

1 2

10.25

21.5

a ab bdh

Page 29: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 29

Resultant forces of two parallel identical elliptical cylinders

Page 30: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 30

Case 3: One circular and one elliptical cylinders

1

1

2

10.250.5

21.5

abadh

Page 31: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 31

Resultant forces of two cylinders containing one circular and one elliptical cylinder

Page 32: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 32

Outline

• Introduction of NTOU/MSV group• Motivation and problem statement• Method of solution• Illustrative examples• Conclusions

Page 33: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 33

Conclusions

1. The higher accurate and faster convergence rate of the present method over the EBM is observed

2.Null-field BIEM in conjunction with adaptive observer system and the degenerate kernel can solve water wave problems containing circular and elliptical cylinders in a semi-analytical way.

3. This method also belongs to a meshless method since collocation points on the boundaries are only required.

Page 34: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 34

The endThanks for your kind attentions

http://msvlab.hre.ntou.edu.tw/Welcome to visit the web site of MSVLAB/NTOU

Page 35: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 35

Extension (circle to ellipse)Expand fundamental solution by using the degenerate kernel

0

0

( ) ( ), ,( , )

( ) ( ), ,

s

s

j jj

j jj

F GU

F G

x

x

x ss x

s x

x( , ) x x

x( , ) x x

s ( , )s s

s ( , )s s

Page 36: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 36

Degenerate kernels(polar coordinates)

Page 37: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 37

Four degenerate kernels(elliptic coordinates)

Page 38: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 38

Adaptive observer systems and linear algebraic equations

{} { }[ ] [ ] ,U t T u={} { }[ ] [ ] .L t M u=

Collocation point Collocation point

Boundary contour integration Boundary contour integration

Page 39: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 39

木櫃期刊雜誌技術報告博碩士論文論文資料MSC/NASTRAN

鐵櫃CTEX

軟體使用手冊圖書文具

國立台灣海洋大學力學聲響振動實驗室 (NTOU/MSV Lab)負責老師:陳正宗 終身特聘教授 ( 海洋大學河海工程學系 ) 地點:河工二館 HR2306 室  陳義麟 副教授 ( 高雄海洋科技大學造船學系 ) 聯絡電話: 886-2-24622192 ext.6177 or 6140 李為民 副教授 ( 中華技術學院機械系 ) URL : http://ind.ntou.edu.tw/~msvlab 呂學育 助理教授 ( 中華技術學院航空機械系 ) E-mail: [email protected] 陳桂鴻 副教授 ( 國立宜蘭大學土木系 ) Fax: 886-2-24632375  徐文信 助理教授 ( 屏東科技大學教學資源中心 ) 范佳銘 助理教授 ( 海洋大學河海工程學系 )

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期刊論文 期刊論文 期刊論文 期刊論文

Page 40: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 40

Elliptic coordinates and Mathieu function

?

2

2ckq

:

:

angular coordinateradial coordinate

2cMathieu function

Modified Mathieu function

( , ), 0,1 ,( )

( , ), 1, 2 ,m

m

Se q mA

So q m

( , ) ( , ), 0,1 ,( )

( , ) ( , ), 1, 2 ,m m m m

m m m m

Je q Ye q mB

Jo q Yo q m

( ) )) (( BAu x

Page 41: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 41

Resultant forces of a circular cylinder

Number of degree of freedom

Page 42: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 42

Degenerate (separable) form of fundamental solution (1D)

-10 10 20

2

4

6

8

10

Us,x

1 ( s),1 2( , )

12 (s ),2

Ux x s

s x x sx s x

ìïï - ³ïïï= - =íïï - >ïïïî

-10 10 20

-0.4

-0.2

0.2

0.4

Ts,xs

continuouscontinuous jumpjump1 ,2( , )

1 ,2

Tx s

s xs x

ìïï - >ïïï=íïï >ïïïî

Page 43: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 43

Elliptic coordinates and Mathieu function

?

2

2ckq

:

:

angular coordinateradial coordinate

2cMathieu function

Modified Mathieu function

( , ), 0,1 ,( )

( , ), 1, 2 ,m

m

Se q mA

So q m

( , ) ( , ), 0,1 ,( )

( , ) ( , ), 1, 2 ,m m m m

m m m m

Je q Ye q mB

Jo q Yo q m

( ) )) (( BAu x

Page 44: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 44

Difference between the 33rd CTAM and present work

33rd CTAM Present work

Interior problemEigenproblems

Interior problemWater wave problems

Page 45: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 45

Resultant forces of an elliptical cylinder

[3] Au M. C. and Brebbia C. A., “Diffraction of water waves for vertical cylinders using boundary elements”, Applied Mathematical Modelling, Vol. 7, (1983), pp 106-114.

Page 46: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 46

Boundary densities

0 1

( ) cos( ) sin( ), ,n nn n

u g n h n B

s ss s

0 1

( ) cos( ) sin( ), ,n nn n

t p n q n B

s ss s

0 1

( ) ( , ) ( , ), ,n n n nn n

u g Se q h So q B

s ss s

0 1

1( ) ( , ) ( , ) , ,n n n nn n

t p Se q q So q BJ

s ss

s s

Expand boundary densities by using the Fourier series and eigenfunction expansion

2c

Circular boundaries

Elliptical boundaries

Page 47: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 47

Expansions of incident plane wave using the polar and the elliptic coordinates

0

( ) ( ) ( )cos( ( )),nI n n

n

u i J k n

x xx

0 1

( , ) ( , )( ) 8 ( ) ( , ) ( , ) ( ) ( , ) ( , ) ,

( ) ( )n nn n

I n n n ne on nn n

Se q So qu i Se q Je q i So q Jo q

M q M q

x x x xx

Circular boundaries

Elliptical boundaries

Page 48: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 48

Boundary densitiesExpand boundary densities by using the eigenfunction expansion

0 1

1( ) ( , ) ( , ) , ,n n n nn n

t p Se q q So q BJ

s ss

s s

0 1

( ) ( , ) ( , ), ,n n n nn n

u g Se q h So q B

s ss s

2 2

1.1

1.2

1.3

1.4

1.5

1.6Js

is a constants along the elliptical boundarys

11

c

s

2c

Page 49: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 49

Successful experiences in 2-D eigenproblems with circular boundaries

0 ( ) ( )( , ) ( , ( ) ( ))B BT d tUu B dB s sxsx ss s

Kuo et al. Int. J. Numer. Meth. Engng. 2000

Key point Degenerate kernel(Polar coordinates)

0 ( ) ( )( , ) ( , ( ) ( ))B B

M d tLu B dB s sxsx ss s

UT equation

LM equation

Spurious eigenvalues Spurious eigenvalues

Chen et al. Proc. R. Soc. Lond., Ser. A, 2002 & 2003

KernelReal-part

Imaginary-part

Complex-valued kernelUT or LM

Inner boundary

(Found and treated)

(Singular)

(Hypersingular)

Page 50: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 50

Elliptic coordinates and Mathieu function2

2ckq

:

:

angular coordinateradial coordinate

2cMathieu function

Modified Mathieu function

( , ), 0,1 ,( )

( , ), 1, 2 ,m

m

Se q mA

So q m

( , ) ( , ), 0,1 ,( )

( , ) ( , ), 1, 2 ,m m m m

m m m m

Je q Ye q mB

Jo q Yo q m

( ) )) (( BAu x

Page 51: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 51

Degenerate kernels

Modified Mathieu functions of the third kind

(1)0 ( )

( , )2

i H krU

s x r s x

Addition theorem (Morse and Feshbach’s book)

0 1

( , ) ( , )2 ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ,( ) ( )

( , )( , ) ( , )2 ( , ) ( , ) ( , )

( ) ( )

m mm m m m m me o

m mm m

m mm m me o

m m

Se q So qi Se q Je q He q So q Jo q Ho qM q M q

USe q So qi Se q Je q He q S

M q M q

s ss s s

s ss

s x

0 1

( , ) ( , ) ( , ) ,m m mm m

o q Jo q Ho q

s s

Orthogonal relations

Methods of Theoretical Physics, 1953, p.1421

Analytical study

(norm)

Page 52: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 52

Successful experiences in 2-D problems with circular boundaries

using the present approach)()()( sdBsx

B ),( xsK

),( xsK e

Fundamental solutionFundamental solution

Advantages of present approach:1. No principal value2. Well-posed model3. Exponential convergence4. Free of mesh generation

Degenerate kernelDegenerate kernel

xsxsKxsxsK

e

i

),,(),,(

),( xsK i

sx ln

The proposed approach will be extended to

deal with 2-D problem with elliptic boundaries

)()1(0 sxkH

(Laplace)(Helmholtz)

Page 53: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 53

Why spurious solution occurs

• FDM for ODE

• Real-part BEM & MRM (Simply-connected problem)

• Complex-valued BEM (Multiply-connected problem)

Page 54: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 54

Separation of variables in the elliptic coordinates

2 2 2 2( ) ( )cosh(2 ) cos(2 )( ) 2 ( ) 2

B k c A k c pB A

2 22 cos(2 ) 0,

42 cosh(2 ) 0

A q G c kqB q F

p

p

2 2 2 2

2 2 cosh(2 ) cos(2 02

u u k c u

2 2

22 22 2 2

1 0sinh ( ) sin ( )

u u k uc

2 2( , ) ( , ) 0u k u Elliptic coordinates 2 2( , ) ( , ) 0u x y k u x y Cartesian coordinates

( , ) ( ) ( )u A B separation of variables

Page 55: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 55

Addition theorem

n

innn

n erkJbkJ

rbkJakJ

)(

00

1|)|(|)|()1(

|)|(|)|(

sincoscossin)sin(

ra

b

1

2

Q

O

P

a

sxsx eee

= + sinsincoscos)cos(

Addition theorem

s

xsxsxsx

eeeeee )(

n

innn ebkJakJ

bakJbakJrkJ

)(

000

2|)|(|)|(

|))(|(|)|(|)|(

Subtraction theorem

rb

Page 56: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 56

Degenerate (separable) form of fundamental solution (2D)

1

1

1ln c

1ln c

( , ) lnos

s ,

,

o

m

m

m

m

R mU

R mR

m

m

Rr

R

s x

, , , ,R r s x x s

( , )R s

( , ) x

( , ) x

CircleExtension

Ellipse

0

0

( ) ( ), ,( , )

( ) ( ), ,

s

s

j jj

j jj

F GU

F G

x ss x

s x

Page 57: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 57

Degenerate cases in mathematics and mechanics

Page 58: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 58

Jump behavior across the boundary

2

0

2 2

(s,x) (s,x) cos

cos cos

cos

2 cos , x

i e

n n n n n n

m m m m

T T n Rd

kR J kR Y kR iJ kR n kR J kR Y kR iJ kR n

kR Y kR J kR Y kR J kR n

n B

2,m m m m m mW J kR Y kR Y kR J kR Y kR J kRkR

x BÎ WÈ

x c BÎ W È

cW

W

2 (x) (s, x) (s) (s) (s, x) (s) (s)i i

B Bu T u dB U t dBp = -ò ò

0 (s,x) (s) (s) (s,x) (s) (s)B

e

B

eT u dB U t dB= -ò ò

2

0

2 2

(s, x) (s,x) cos

cos cos

0, x

i e

n n n n n n

U U n Rd

R J kR Y kR iJ kR n R J kR Y kR iJ kR n

B

Page 59: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 59

Other applications

Electromagnetics

Acoustics1. Hermetic compressor

2. Small automotive muffler

1. Waveguides

TM mode (Dirichlet BC)

TE mode (Neumann BC)

Water wave1. Harbor resonance

Page 60: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 60

Literature review

Page 61: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 61

Literature review

1. Tai and Shaw 1974 (complex-valued BEM)

2. De Mey 1976, Hutchinson and Wong 1979 (real-part kernel)

3. Wong and Hutchinson (real-part direct BEM program)

4. Shaw 1979, Hutchinson 1988, Niwa et al. 1982 (real-part kernel)

5. Tai and Shaw 1974, Chen et al. Proc. Roy. Soc. Lon. Ser. A, 2001, 2003 (multiply-connected problem)

6. Chen et al. (dual formulation, domain partition, SVD updating technique, CHEEF method)

Mathematical analysis and numerical study for free vibration of plate using BEM-61

Page 62: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 62

The orthogonality of vector and function

1e

2e

3e

1,0,i j

if i je e

if i j

vectors

functions ( ) ( ) ( ) 0b

aw x A x B x dx ( )A x ( )B xand are orthogonal

1 2

2 3

3 1

e ee ee e

Mathieu function

Orthogonal relations (norm)

Page 63: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 63

Jacobian

LJ arc length

AJ (Area)

2 2sinh( ) cos( ) cosh( )sin( )

ds Jd

J c

2 22 2sinh( )cos( ) cosh( )sin( )

dA Jd d

J c c

Elliptic coordinatesPolar coordinates

2 2ds dx dy

dA dxdy

ds JdJ

dA Jd d

J

, ,x y , ,x y

cosh cos

sinh sin

x c

y c

cossin

xy

,x y ,x y

Page 64: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 64

Adaptive observer system

collocation pointcollocation point

0 , 01 , 1k , k2 , 2

Page 65: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 65

Linear algebraic equation

{}

0

1

2

N

tt

t t

t

ì üï ïï ïï ïï ïï ïï ïï ï=í ýï ïï ïï ïï ïï ïï ïï ïî þM

[ ]00 01 0

10 11 1

0 1

N

N

N N NN

é ùê úê úê ú= ê úê úê úê úë û

U U UU U U

U

U U U

LL

M M O ML

Column vector of Fourier coefficientsColumn vector of Fourier coefficients((NthNth routing circle) routing circle)

0B

1B

Index of collocation circleIndex of collocation circle

Index of routing circle Index of routing circle

2B

NB

[ ]{} { }[ ]t uU T=

Page 66: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 66

Literature review (Degenerate kernel )

Author ApplicationsSloan et al.(1975)

Prove that it is equivalent to iterated Petrov-Galerkin approximation

Kress(1989)

Prove that the integral equation combined with degenerate kernel has convergence of exponential order

Chen et al.(2005)

Applied it to solve engineering problems with circular boundaries

Chen et al.(2007)

Link Trefftz method and method of fundamental solutions

However, its applications in practical problems seem to have taken a back seat to other methods. ~ M. A. Golberg 1979

Degenerate kernel approximation

(Schaback)

Page 67: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 67

Hypersingular integralH.P.V.(Hadamard principal value)

1

433

2

002

00

0sin14

)()(

2-sin4

1-

,Nn

nN

ddLLq

Principle value version Series summability version

x

1 1

2 21 10

1 1 2. . . lim = 2 H PV dx dxx x

1D2D

NTOU/MSV D. H. Yu

Page 68: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 68

Other degenerate kernels-1

.,)(cos1ln21),;,(

,,)(cos1ln21),;,(

),(

1

1

RmRm

RU

RmRm

RRU

xsU

m

me

m

mi

0

)1(

0

)1(

,)),(cos()()(4

),;,(

,)),(cos()()(4

),;,(),(

mmmm

e

mmmm

i

RmkRJkHiRU

RmkRHkJiRUxsU

(2-D circular Laplace problem)

(2-D circular Helmholtz problem)

(2-D circular biHelmholtz problem)

32 2

2

222

32 2

2

22

1( , ) (1 ln ) ln [ (1 2ln ) ]cos( )2

1 1[ ]cos[ ( )],( 1) ( 1)

( , ) ln1( , ) (1 ln ) ln [ (1 2ln ) ]cos( )2

1 1[ ]co( 1) ( 1)

I

m m

m mm

E

m m

m mm

U s x R R R R RR

m Rm m R m m R

U s x r rRU s x R R

R Rm m m m

s[ ( )],m R

(2-D circular biharmonic problem)

Page 69: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 69

Other degenerate kernels-2

0 1

( , ) ( , )2 ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ,( ) ( )

( , )( , ) ( , )2 ( , ) ( , ) ( , )

( ) ( )

m mm m m m m me o

m mm m

m mm m me o

m m

Se q So qi Se q Je q He q So q Jo q Ho qM q M q

USe q So qi Se q Je q He q S

M q M q

s ss s s

s ss

s x

0 1

( , ) ( , ) ( , ) ,m m mm m

o q Jo q Ho q

s s

11 0

11 0

1 ( )!cos ( ) (cos ) (cos ) ,( )!1( , )

1 ( )!cos ( ) (cos ) (cos ) ,( )!

nni m m

m n n nn m

nne m m

m n n nn m

n mU m P P RR n m R

U s xr n m RU m P P R

n m

,)],(cos[)()()(cos)(cos)!()!()12(

4),,;,,(

,)],(cos[)()()(cos)(cos)!()!()12(

4),,;,,(

),()2(

0 0

)2(

0 0

mkhkjPPmnmnnikU

mkhkjPPmnmnnikU

xsUnn

mn

mn

n

n

mm

e

nnm

nm

nn

n

mm

i

(3-D spherical Lalace problem)

(2-D elliptical Laplace problem)

,,sinsinsinh2coscoscosh22

ln21),;,(

,,sinsinsinh2coscoscosh22

ln21),;,(

),(

11

11

m

m

m

me

m

m

m

mi

mmmem

mmmem

aU

mmmem

mmmem

cUxsU

(3-D spherical Helmholtz problem)

(2-D elliptical Helmholtz problem)

Page 70: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 70

Other degenerate kernels-3

( )

1

( )

1

( )

1ln(2 ) cos ( ) cos( ) cos( ) , 0

1( , ) ln(2 ) cos ( ) cos( ) cos( ) , 0

1ln(2 ) cos ( ) cos( ) cos

s s

s s

s s

n nns s s s

n

n nns s s

n

n nns

c e n e n e nn

U s x c e n e n e nn

c e n e n en

1

( ) , 0s sn

n

1( )( )2

0 0

1 ( )!cos ( ) (cos( )) (cos( )) ,( )!1( , )

1 ( )!cos ( ) (co

cosh( ) cos( ) cosh( ) cos( )

cosh( ) s( )) (coscos( ) cosh( ) ( )cos( ) )( )!

sn

nm mm s n s n s

n m

m mm s n s n

s s

s s

n m m P P ec n m

U x sr n m m P P

c n m

1( )( )2

0 0

,sn

ns

n m

e

,,))1()1cos(()())2(cos()(121))(cos()(1ln)43(

)1(81),;,(

,,))1()1cos(()())2cos(()(121))(cos()(1ln)43(

)1(81),;,(

),(

0

1

0111

0

1

0111

11

RmmRmmRmRmG

RU

RmmR

mmR

mRm

RG

RUxsU

m

m

m

m

m

me

m

m

m

m

m

mi

(Circular Navier problem)

(Two circles(bipolar) Laplace problem)

(Two spheres(bispherical) Laplace problem)

Page 71: Date: Jan. 13, 2010 Time: 11:50~12:10  Place: Lectrue Theater F

The 8th Asian Computational Fluid Dynamics ConferenceHong Kong, 10-14 January, 20102010/01/13 Page 71

Orthogonal coordinate systems2D 3D

Cartesian Cartesian

Polar Sphere

EllipticOblate spheroidalProlate spheroidal

BipolarBispherical

Toroidal

Parabolic


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