Multimodal Method in Sloshing Analysis Analytical Mechanics Concept

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    Multimodal Method in Sloshing Analysis:Analytical Mechanics Concept

    byAlexander Timokha

    CeSOS/AMOS, NTNU, Trondheim,

    NORWAY

    &

    Institute of Mathematics,

    National Academy of Sciences of Ukraine,UKRAINE

    Trondheim, 28. May, 2013

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    Multimodal Method in Sloshing Analysis:Analytical Mechanics Concept

    Etymology comes from

    which is the most cited paper on sloshing of the last two decades

    CONCE

    PT

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    Multimodal Method in Sloshing Analysis:

    Analytical Mechanics Concept

    The concept originally appeared in XIX century but generalized in 2000-2013 by

    the author together withProf. Odd M. Faltinsen

    Liquid Sloshing Dynamicsistreated as aconservative mechanical system with infinite degrees of freedomso that

    the Lagrange formalism can adopt thegeneralized coordinates andvelocities

    responsible for the global liquid modes instead of working with typically-

    accepted hydrodynamic characteristics (velocity field, pressure, etc.)

    CONCE

    PT

    Historical aspects & Ideas: Linear & Nonlinear

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    IDEAS come from aircraft and spacecraft applications:

    when the task consists of describing

    the coupled dynamics of

    a body with cavities filled by a liquidN.E. Joukowski (1885) paper

    `On the motion of a rigid body with cavities

    filled by a homogeneous fluid

    Joukowski theorem for a completely filled tank:

    `The rigid body-ideal irrotational incompressible fluid mechanical

    system can modelled as a rigid body with aspecifically-modifiedinertia

    tensor

    Considering the fluid as frozen is a wrong way (boiled and fresheggs!!!).

    The velocity field is described by the so-called Stokes-Joukowski

    potentials.

    H

    ISTORY&

    IDEAS

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    by the liquid:

    ideal, incompressible,

    irrotational flow

    Translatory velocity:

    Instant angular velocity:1 2 2( ) ( ( ), ( ), ( ))Ov t t t t

    4 5 6( ) ( ( ), ( ), ( ))t t t t

    The liquid velocity potential

    0( ) ( )( , , , ) ( , , ), ( , , )Ox y v t tz t x z r x y z y r

    the Stokes-Joukowski potential

    FULLY FILLED TANK

    H

    ISTORY&

    IDEAS

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    Having known the time-independentStokes-

    Joukowski potentials makes it possible to find the

    fluid flow for any time instant so that

    the velocity field the pressure,

    the resulting hydrodynamic force and moments,etc.

    are explicit functions of the six input generalized

    coordinates

    What about liquid sloshing (free surface)?

    H

    ISTORY&

    IDEAS

    LINEAR SLOSHING

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    LINEAR SLOSHING,

    50-60s of XX century

    Liquid:

    ideal

    incompressible irrotational flow

    1 2 2( ) ( ( ), ( ), ( ))Ov t t t t

    4 5 6( ) ( ( ), ( ), ( ))t t t t

    0( , , , ) ( )

    ( , , )

    ( , , ) ( , , )

    ( , ,( )) 0

    ( ) ( ) NO

    N

    N

    NN

    N

    r x y z x x y z t R t

    x y

    yv t z

    x

    t

    z t t y

    sloshing modesinterpreted as generalized coordinates

    (infinite set!!!)

    Free surface

    generalized velocities

    H

    ISTORY&

    IDEAS

    Joukowski solution

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    As long as we know

    the time-independent Stokes-Joukowski potentials(Neumann problem in the unperturbed liquid domain)

    the natural sloshing modes (the spectral boundary problemin the unperturbed liquid domain)then

    the free-surface elevations

    the hydrodynamic forces and moments (provided by the

    corresponding Lukovsky formulas)

    are functions of the input and the generalized coordinates

    where the latters are the solution of the linear oscillator

    problem:

    and the hydrodynamic coefficients are integrals over

    and

    0( , , )x y z

    ( , , )N

    x y z

    60( 3)2 1 2

    41 5 2 4

    ( ) ( ) , 1,2,...k mm m

    m mkm m

    k

    m

    mg g m

    ( , , )N x y z

    0( , , )x y z

    H

    ISTORY&

    IDEAS

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    ( )

    free surface ( ): , , , 0

    subject to volume conservation

    (

    0

    )N

    Q t

    t Z x y z

    dQ

    t

    NONLINEAR MULTIMODAL METHOD:new life in 00s

    Liquid:

    ideal

    incompressible irrotational flow

    1 2 2( ) ( ( ), ( ), ( ))Ov t t t t

    4 5 6( ) ( ( ), ( ), ( ))t t t t

    0( , , , ) ( , , ,{ ( )} ( )) ( , , )N NON

    N t R tx y z t r x y z x y zv

    The free surface elevations, the hydrodynamic forces and moments

    also remain functions of the six inputandinfinite setof the free-

    surfacegeneralized coordinates

    Generalized velocities

    Generalized coordinatesH

    ISTORY&

    IDEAS

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    THERE ARE

    APPLIEDMATHEMATICAL &

    PHYSICAL

    PROBLEMSTO BE SOLVED

    TO IMPLEMENT

    THE NONLINEAR

    MULTIMODALMETHOD

    H

    ISTORY&

    IDEAS

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    The nonlinear multimodal method

    1. The method is ofanalytical nature.

    What are analytical limitations?2. The Euler-Lagrange equation for

    liquid sloshing dynamics

    3. Physical and mathematical argumentsfor choosing the generalized

    coordinates

    4. How does it work?

    Themultimodalmethod

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    A. For any instant must be defined

    in the time-varied liquid domain

    and satisfy the tank surface conditionB. Derivation of the Euler-Lagrange

    equations with respect to the

    generalized coordinates and velocities

    ( , , )N x y z

    ( )Q t

    hand-made

    product for each

    tank shape

    e.g., the

    Bateman-Luke

    variational

    principle

    MATH

    EMATICALL

    IMITATIONS

    Bateman-Luke

    variational principle

    derives the Euler-

    Largange equation

    The following problems must be solvedanalytically:

    Assuming A (we know analytical modes):

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    (Kinematic Eq.): , changingd

    ;d

    N N K NK K K KK

    A AA F

    tN

    (Dynamic Eq.):

    1 2 31 2 changing1 ... 02K KLK K L

    K KLN N N N N

    A A l l l F NF F

    where

    * *( ) ( )

    1 * 2 * 3 *( ) ( ) ( )

    d ; d ,

    d ; d ; d

    N N N NK N N K Q t Q t

    N N NQ t Q t Q t

    A Q A Q

    l x Q l y Q l z Q

    EULE

    R-LAGRANG

    EEQUATION

    Application needs a finite-dimensional form in application,

    so how to use the Euler-Lagrange equation, e.g., for

    Steady-state and transient response? Wave elevations? Forces and moments? Coupling? Realistic clean tanks? Dissipation? Internal structures effect?

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    Problems to be solvedanalytically:

    A. For any instant must be defined

    in the time-varied liquid domain

    and satisfy the tank surface conditionB. Derivation of the Euler-Lagrange

    equations with respect to the

    generalized coordinates and velocities

    C. Reduction of the infinite-dimensionalEuler-Lagrange equations to a finite-

    dimensional form

    D. Accounting for specific phenomena

    neglected by the physical model

    (damping, inner structures, wall/roof

    impact, perforated bulkhead, and so on)

    ( , , )N x y z

    ( )Q t

    hand-made

    product for each

    tank shape

    e.g., the

    Bateman-Luke

    variational

    principle

    Normally,

    asymptotic

    approaches

    results of the last

    decade

    PH

    YSICALAGR

    UMENTS

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    HOW does it work?

    Lets considerdevils examples for:

    1. For 2D flows2. For 3D rectangular tanks with upright

    walls

    3. For complex tank shapesHowdoesit

    work?

    What should be solved?

    Choosing the leading and negligible

    generalized coordinates Modifying the modal equation due to

    damping, specific phenomena and internal

    structures

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    When forcing the lowest natural sloshing frequency:Finite liquid depth (liquid depth/tank length>0.2)

    A small forcing magnitude Moiseevs asymptotics

    Increasing forcing magnitude, or the critical depth

    ratio (h/l=0.3368) secondary resonances andadaptive asymptotics

    Intermediate and small depths (liquid depth/tanklength < 0.2)

    Multiple secondary resonance

    Boussinesq ordering

    Internal structures (e.g., bulkheads)

    Small forcing amplitude quasilinear theory

    Increasing forcing amplitude secondary resonance

    Nonlinearity implies an energy transfer from the lowest,primary excited, to a set of higher modes. The lattermodes can be resonantly excited due to the so-calledsecondary resonances.

    What does it mean in terms of leading

    generalized coordinates?

    2Dinrectangulartank

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    When forcing the lowest natural frequency:Finite liquid depth (liquid depth/tank length>0.2)

    A small forcing magnitude Moiseevs asymptotics

    Increasing forcing magnitude, or the critical depth ratio

    (h/l=0.3368) secondary resonances and adaptiveasymptotics

    Intermediate and small depths (liquid depth/tanklength < 0.2)

    Multiple secondary resonance

    Boussinesq ordering

    Internal structures (e.g., bulkheads)

    Small forcing amplitude quasilinear theory

    Increasing forcing amplitude secondary resonance

    Nonlinearity implies an energy transfer from the lowest,primary excited, to a set of higher modes. The latter modescan be resonantly excited due to the so-called secondaryresonances.

    What does it mean in terms of leading

    generalized coordinates?

    2Dinrectangulartank

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    Example 1: The Moiseev-type multimodal theory

    The modal solution

    Moiseev proved for the steady-state (periodic) sloshing due toexcitation of the lowest frequency when there are no secondary

    resonances

    01

    1

    12

    ( , , ) ( , ) ( , ),

    ( , ) ( ) ( , 0),

    cosh ( )cos ( )

    cosh( )

    O n nn

    n nn

    n

    y z t v r y z R y z

    z y t t y

    n z hn y

    nh

    1/3 2/3

    1 1

    4

    3

    2

    2 2

    3

    3

    ( ), ( ),

    ( ); ( ), 4

    / / ( ); ( ) 1,

    n n

    R O R O

    R O R O n

    l l O O

    Example1:

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    2

    1 1 2 3

    22

    2 2

    1 1 1 2 1 2 1 1 1 1 2 1

    22 2 1 1 1

    2 2

    3 3 1 2 1 1 2 1 1 1 1

    4 5

    2

    3 1 2 3 4 2 35

    1( ) ( ) ( ) ,

    ( ) 0,

    (

    )

    .

    (

    ) ( )

    d d d

    d d

    q

    K t

    q q tq Kq

    Modal equations

    2 , 4,.( ..,)iii i

    iK Nt

    24 4

    ( )( ) ( ) ( )

    i ii

    gP S

    l l

    tK t t t

    Forcing term:

    Example1:

    Coefficients are analytically found as functions ofthe liquid depth to the tank breadth ratio

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    Tran

    sients:

    Experiments

    Theorywithdifferent

    initialscenarios

    Steady-state waves with the horizontal/angular harmonicforcing,

    the dominant amplitude parameter:

    (frequency , nondimensional amplitude ),

    / 0.3368...h l / 0.3368...h l

    Example1:

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    When forcing the lowest natural frequency:Finite liquid depth (liquid depth/tank length>0.2)

    A small forcing magnitude Moiseevs asymptotics

    Increasing forcing magnitude, or the critical depth

    ratio (h/l=0.3368) secondary resonances andadaptive asymptotics

    Intermediate and small depths (liquid depth/tanklength < 0.2)

    Multiple secondary resonance

    Boussinesq ordering

    Internal structures (e.g., bulkheads)

    Small forcing amplitude quasilinear theory

    Increasing forcing amplitude secondary resonance

    Nonlinearity implies an energy transfer from the lowest,primary excited, to a set of higher modes. The latter modescan be resonantly excited due to the so-called secondaryresonances.

    What does it mean in terms of leading

    generalized coordinates?

    Example2:

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    Example2:

    Exam

    ple2:

    Adaptivemodalsystemsfor

    criticaldepthand

    increasing

    forcin

    gamplitude

    Nonlinear multiple frequency effects excite higher natural frequencies

    Increased importance with decreasing depth and increasing forcingamplitude

    Reason for decreasing depth importance is that when the

    liquid depth goes to zero

    Implies that more then one mode is dominant

    nn

    Diff d i f h li d di d

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    Different ordering of the generalized coordinates due to

    secondary resonances with a finite liquid depth

    Example2:

    Rectangular tank, 1x1m, nearly critical

    depth, h/l = 0.35

    Subharmonicregimes are

    predicted

    I i th f i lit d d ti f f i t h/l 0 4

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    Increasing the forcing amplitude and accounting for roof impact, h/l=0.4

    Example2:

    0.01

    0.1

    impact neglected impact accounted forFlow 3D

    CFD: Symbols and represent numerical results by the viscous

    CFD-code FLOW-3D obtained for fresh water with different internal

    parameters of the code: for alpha=0.5, epsdj=0.01 and foralpha=1.0, epsdj=0.01.

    Experiments: The influence of viscosity: , fresh water; , reginol-

    oil; , glycerol-water 63%, , glycerol-water 85%

    h f i h l l f

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    When forcing the lowest natural frequency:Finite liquid depth (liquid depth/tank length>0.2)

    A small forcing magnitude Moiseevs asymptotics

    Increasing forcing magnitude, or the critical depth ratio

    (h/l=0.3368) secondary resonances and adaptiveasymptotics

    Intermediate and small depths (liquid depth/tanklength < 0.2)

    Multiple secondary resonance

    Boussinesq ordering

    Internal structures (e.g., bulkheads)

    Small forcing amplitude quasilinear theory

    Increasing forcing amplitude secondary resonance

    Nonlinearity implies an energy transfer from the lowest,primary excited, to a set of higher modes. The latter modescan be resonantly excited due to the so-called secondaryresonances.

    What does it mean in terms of leading

    generalized coordinates?

    Example3:

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    Intermediate and small depths normally cause amplification of higher

    modes and a series of local wave breaking & overturning

    Example3:

    A B i t d i b

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    As a consequence, a Boussinesq-type ordering can be

    proven being applicable to with1/4( / ) ( ), 1

    i iO h l O i R

    Transients:

    The measured and calculated wave elevations near the wall for

    horizontal forcing . The solid and dashed

    lines correspond to experiments and the Boussinesq-type

    multimodal method, respectively.

    / 0.173, 0.028h l

    Example3:

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    Example3:

    Steady-state due to harmonic forcing = experiments

    Chester & Bones

    Theory by ChesterMultumodal theory

    / 0.083333h l

    0.001254 0.002583

    Agreement is almost ideal when no wave breaking occurs and,

    therefore, damping does not matter.

    Multi-peak response curves anddamping are important whendealing with secondary resonances.

    Associated damping becomes important with

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    Associated damping becomes important with

    Decreasing depth and increasing forcing amplitude

    Roof impact

    Internal structuresNormally, viscous boundary layer effect is less

    important

    Damping terms can be incorporated into the modalequations following the strategy in Chapter 6 ofSloshing book.

    An open problem is damping due to the local free-surface phenomena:

    Overturning and impact on underlying fluid

    Breaking waves in the middle of the tank

    Examplesvs.damping

    Wh f i th l t t l f

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    When forcing the lowest natural frequency:Finite liquid depth (liquid depth/tank length>0.2)

    A small forcing magnitude Moiseevs asymptotics

    Increasing forcing magnitude, or the critical depth ratio

    (h/l=0.3368) secondary resonances and adaptiveasymptotics

    Intermediate and small depths (liquid depth/tanklength < 0.2)

    Multiple secondary resonance

    Boussinesq orderingInternal structures (e.g., bulkheads)

    Small forcing amplitude quasilinear theory

    Increasing forcing amplitude secondary resonance

    Nonlinearity implies an energy transfer from the lowest,primary excited, to a set of higher modes. The latter modescan be resonantly excited due to the so-called secondaryresonances.

    What does it mean in terms of leading

    generalized coordinates?

    Example4:

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    Example4:

    Examp

    le4:Middle

    screen

    The middle-screen causes: (a) migration of the resonances and super-

    multipeak response curves; (b) damping; (c) disappearance of the

    primary resonance with increasing the solidity ratios

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    Planar waves waves keeps symmetry with respect to the

    excitation plane: occur far from the primary resonance. Swirling exactly at the primary resonance Irregular (chaotic) waves. Weak chaos? For the rectangular shape, a diagonal-type (squares-like) waves

    waves with an angle to the excitation plane

    Three-dimensional: nearly steady-state wave response

    3Dslosh

    ing

    M i t d l t f b t k

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    Moiseev-type modal system for square base tank

    3Dslosh

    ing

    2 2 2 1 51 1, 0 1 1 1 2 1 2 2 1 1 1 1 3 2 1 1, 0 1,0 5

    1 1

    2 26 1 1 1 7 1 8 1 1 9 1 1 10 1 1 11 1 1 1 12 1 1

    ( ) ( )

    ( ) 0,

    ga a d a a a a d a a a a d a a P S L L

    d a b b d c d a b d c b d b a d a b b d b c

    2 2 2 2 41 0,1 1 1 1 2 1 2 2 1 1 1 1 3 2 1 0,1 0,1 4

    1 1

    2 26 1 1 1 7 1 8 1 1 9 1 1 10 1 1 11 1 1 1 12 1 1

    ( ) ( )

    ( ) 0,

    gb b d b b b b d b b b b d b b P S

    L L

    d b a a d c d a b d c a d a b d a b a d a c

    1,0 1 2,0 2 0,1 1 0,2 2 1,1 1 3,0 3 2,1 21 1,2 12 0,3 3; ; ; ; , ; ; ;a a b b c a c c b

    2 2

    2 2, 0 2 4 1 1 5 10;a a d a a d a

    2 2

    2 0,2 2 4 1 1 5 10;b b d b b d b

    21 1 1 1 2 1 1 3 1 1 1,1 1

    0,c d a b d b a d a b c

    2 2 2 1 53 3,0 3 1 1 2 2 1 3 2 1 4 1 1 5 1 2 3,0 3,0 5

    1 1

    ( ) 0,g

    a a a q a q a q a a q a a q a a P S

    L L

    2 2 2

    21 2,1 21 1 6 1 7 1 1 1 8 2 9 1 10 2 1 11 1 1 12 1 1 13 1 1 1 14 1 1 15 2 1( ) ( ) 0,c c a q c q a b b q a q a q a b q c a q a b q a b a q a c q a b

    2 2 2

    12 1,2 12 1 6 1 7 1 1 1 8 2 9 1 10 2 1 11 1 1 12 1 1 13 1 1 1 14 1 1 15 1 2( ) ( ) 0,c c b q c q a b a q b q b q b a q c b q b a q a b b q b c q a b

    2 2 2 2 43 0, 3 3 1 1 2 2 1 3 2 1 4 1 1 5 1 2 0, 3 0,3 4

    1 1

    ( ) 0.g

    b b b q b q b q b b q b b q b b P S

    L L

    Modal equations with nine degrees of freedom

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    For harmonic forcing, one can find analytically

    approximate steady-state solutions and study their stability

    (also analytically!!!). This makes it possible to classify the

    steady-state regimes and establish the frequency ranges

    where the regimes exist and stable.

    One can distinguish:3Dslosh

    ing

    the order (stable steady-state),

    the strong chaos (treated as nostable steady-state for leading generalized coordinates), the weak chaos (here, irregular for higher-

    order generalized coordinates)

    Classification for longitudinal forcing:

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    Classification for longitudinal forcing:

    planar, diagonal (squares)-type, swirling and chaos

    excitation amplitude = 0.0078L

    3Dslosh

    ing

    Classification for longitudinal forcing:

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    3Dslosh

    ing

    Classification for longitudinal forcing:

    planar, diagonal (squares)-type, swirling and chaos

    excitation amplitude = 0.0078L

    Classification for longitudinal forcing:

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    3Dslosh

    ing

    Classification for longitudinal forcing:

    planar, diagonal (squares)-type, swirling and chaos

    excitation amplitude = 0.0078L

    Classification for longitudinal forcing:

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    3Dslosh

    ing

    Classification for longitudinal forcing:

    planar, diagonal (squares)-type, swirling and chaos

    excitation amplitude = 0.0078L

    Classification for longitudinal forcing:

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    3Dslosh

    ing

    Classification for longitudinal forcing:

    planar, diagonal (squares)-type, swirling and chaos

    excitation amplitude = 0.0078L

    Classification for longitudinal forcing:

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    3Dslosh

    ing

    Classification for longitudinal forcing:

    planar, diagonal (squares)-type, swirling and chaos

    excitation amplitude = 0.0078L (relatively large!!!)

    Local phenomena for 3D, but the classification is Ok.

    Why? Why is the Moissev-type model still applicable?

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    The method was developed in

    2012, after the book issued

    Sphericaltanks

    3Dslosh

    ing

    ( and ) radius 0 1205 m ( and ) 0 2615 m ( and ) 0 4065

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    11secondary resonance by (01) a0 t /2 0 44. .9h

    (and ) radius 0.1205 m ( and) 0.2615 m ( and) 0.4065

    Classificationof3Dsloshing

    ( and ) radius 0 1205 m ( and ) 0 2615 m ( and ) 0 4065

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    (and ) radius 0.1205 m ( and) 0.2615 m ( and) 0.4065

    secondary resonance is far from the r e0.6 angh

    Classificationof3Dsloshing

    ( and ) radius 0 1205 m ( and ) 0 2615 m ( and ) 0 4065

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    (and ) radius 0.1205 m ( and) 0.2615 m ( and) 0.4065

    11secondary resonance by (22) a1 t /0 1 33. .0h

    Classificationof3Dsloshing

    Swirling wave patterns taken for these input parameters from

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    g p p p

    T.Hysing (1976) Det Norske Veritas, Hvik, Norway

    Specifically,

    splashing,steep wave patterns,

    local breaking.Classificationof3Dsloshing

    ( and ) radius 0 1205 m ( and ) 0 2615 m ( and ) 0 4065

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    (and ) radius 0.1205 m ( and) 0.2615 m ( and) 0.4065

    111.0 secondary resonance by (22) at / 1.033h

    Classificationof3Dsloshing

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    `planar splashing: ``...drops splashed from the tank wall and

    showered through the ullage...''but wave patterns remain planar

    for 1 splashing (planar & swirling type) is all the frequency rangeh

    Classificationof3Dsloshing

    Swirling always causes secondary resonances and

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    Swirling always causes secondary resonances and

    local phenomena when forcing amplitude increases,

    but classification remains correct. Again, why?

    This is explained by the concept of the weak chaos:Here, a clearly steady-state by a subset of [leading]

    generalized coordinates andirregular motions by other

    [infinite set] higher-order coordinates caused by higher

    resonances.

    Weakc

    haosinslosh

    ingproblem

    s

    The weak chaos concept for low-dimensional Hamiltonian

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    Weakc

    haosinslosh

    ingproblem

    s

    p

    (conservative) systems (see, e.g. Henning et al. (2013),

    Physica D, 253):

    ORDERWEAK CHAOS CHAOSLyapunov exponent: 0, but small >0, finite in domains of weak chaos trajectories (by higher-order generalized

    coordinates) slowly diffuse into thin chaotic layers and wander through a

    complicated network of higher order resonances

    For ouralmost-conservative mechanical system with an infinite set of

    generalized coordinates (g.c.), this implies:

    ORDER WEAK CHAOS CHAOSstable by all g.c. stable by dominant g.c., unstable by all g.c.

    but chaos in higher-order g.c.

    unless a strong damping occurs

    For 3D sloshing, the weak chaos is the reality well modelled by

    the multimodal method

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    Longitudinal resonant excitation with h/L=0.5 and

    for a square-base tank. Higher-order (secondary) resonances.

    0.00817 =

    Fromt

    heordertoweakchaosa

    nd,

    thereafter,strongchaosforswir

    lingwith

    increasingtheforcingamplitude

    Swirling(weakchaos)

    Swirling(weakchaos)

    stron

    gchaos

    stron

    gchaos

    order

    o

    rder

    order

    order

    Weakc

    haosinslosh

    ingproblem

    s

    Open problems within the framework of the

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    Open problems within the framework of the

    same paradigm, i.e., six degrees of freedomfor

    the rigid tank andgeneralized coordinatesfor

    the free surface motions:

    Openproblems:intensive

    1. Different internal structures.

    2. Accounting for damping due to wave

    breaking, overturning, etc.

    3. Complex tank shapes.

    4. Order weak chaos chaos.

    5. Importance of weak chaos for coupledmotions

    CFD are normally unapplicable on the long-time scale!

    Input has more than six

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    p

    (infinite) degreesof freedom:

    inflow-outflow & sloshing

    (damaged ship tank, waveenergy, etc.);

    elastic/hyperelastic tank

    walls (fish farms,

    membrane tanks, etc.);

    ship collapse

    Openproblems:extensive

    REFERENCES

    B k

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    Books:

    1. Faltinsen, O.M., Timokha A.N. (2009): Sloshing. Cambridge University Press. 608pp. (ISBN-13:

    9780521881111) Chinese Version of the book issued in 2012: P.R.C.:National Defense Industry Press. 783pp.

    (ISBN-13: 978-7-118-08608-3)

    2. Gavrilyuk, I.P., Lukovsky, I.A., Makarov, V.L., Timokha, A.N. (2006): Evolutional problems of the contained

    fluid. Kiev: Publishing House of the Institute of Mathematics of NASU. 233pp. (ISBN 966-02-3949-1)

    Selected papers in peer-reviewed journals:

    1. Faltinsen, O.M., Timokha, A.N. (2013): Multimodal analysis of weakly nonlinear sloshing in a spherical

    tank.Journal of Fluid Mechanics, 719, 129-164

    2. Faltinsen, O.M., Timokha, A.N. (2012):Analytically approximate natural sloshing modes for a spherical

    tank shape.Journal of Fluid Mechanics, 703, 391-401

    3. Faltinsen, O.M., Timokha, A.N. (2012): On sloshing modes in a circular tank.Journal of Fluid Mechanics,

    695, 467-477

    4. Gavrilyuk, I., Hermann, M., Lukovsky, I., Solodun, O., Timokha, A. (2012): Multimodal method for linear

    liquid sloshing in a rigid tapered conical tank.Engineering Computations, 29, No 2, 198-220

    5. Lukovsky, I.A., Ovchynnykov, D.V., Timokha, A.N. (2012): Asymptotic nonlinear multimodal method for

    liquid sloshing in an upright circular cylindrical tank. Part 1: Modal equations.Nonlinear Oscillations, 14,

    No 4, 512-525

    6. Lukovsky, I.A., Timokha, A.N. (2011): Combining Narimanov--Moiseev' and Lukovsky--Miles' schemes for

    nonlinear liquid sloshing.Journal of Numerical and Applied Mathematics, 105, No 2, 69-827. Faltinsen, O.M., Firoozkoohi, R., Timokha, A.N. (2011): Effect of central slotted screen with a high solidity

    ratio on the secondary resonance phenomenon for liquid sloshing in a rectangular tank.Physics of Fluids, 23,

    Issue 6, Art. No. 062106, 1-13

    8. Faltinsen, O.M., Firoozkoohi, R., Timokha, A.N. (2011): Analytical modeling of liquid sloshing in a two-

    dimensional rectangular tank with a slat screen.Journal of Engineering Mathematics, 70, 1-2, 93-109

    9. Faltinsen, O.M., Firoozkoohi, R., Timokha, A.N. (2011): Steady-state liquid sloshing in a rectangular tank

    with a slat-type screen in the middle: Quasilinear modal analysis and experiments. Physics of Fluids, 23, Issue

    http://www.cambridge.org/us/catalogue/catalogue.asp?isbn=9780521881111http://www.imath.kiev.ua/~tim/PAPERS/book2006.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/book2006.pdfhttp://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8834748http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8834748http://www.imath.kiev.ua/~tim/PAPERS/JFM2012b.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/JFM2012b.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/JFM2012b.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/JFM2012.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/EC_2012.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/EC_2012.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/NO_2011.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/NO_2011.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/JNAM_2011.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/JNAM_2011.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/POF2011+.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/POF2011+.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/JEM_2011.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/JEM_2011.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/JEM_2011.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/JEM_2011.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/POF2011+.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/POF2011+.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/JNAM_2011.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/JNAM_2011.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/NO_2011.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/NO_2011.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/EC_2012.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/EC_2012.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/JFM2012.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/JFM2012b.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/JFM2012b.pdfhttp://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8834748http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8834748http://www.imath.kiev.ua/~tim/PAPERS/book2006.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/book2006.pdfhttp://www.cambridge.org/us/catalogue/catalogue.asp?isbn=9780521881111http://www.imath.kiev.ua/~tim/PAPERS/POF2011-.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/POF2011-.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/POF2011-.pdfhttp://www.imath.kiev.ua/~tim/PAPERS/POF2011-.pdf
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    with a slat type screen in the middle: Quasilinear modal analysis and experiments.Physics of Fluids, 23, Issue

    4, Art. No. 042101, 1-19

    10. Faltinsen, O.M., Timokha, A.N. (2011):Natural sloshing frequencies and modes in a rectangular tank with a

    slat-type screen .Journal of Sound and Vibration, 330, 14901503

    11. Barnyak, M., Gavrilyuk, I., Hermann, M., Timokha, A. (2011):Analytical velocity potentials in cells with a

    rigid spherical wall.ZAMM, 91, No 1, 3845

    12. Faltinsen, O.M., Timokha, A.N. (2010): A multimodal method for liquid sloshing in a two-dimensionalcircular tank.Journal of Fluid Mechanics, 665, 457-479

    13. Hermann, M., Timokha, A. (2008): Modal modelling of the nonlinear resonant fluid sloshing in a rectangular

    tank II: Secondary resonance.Mathematical Models and Methods in Applied Sciences, 18, N 11, 1845-1867

    14. Gavrilyuk, I., Hermann, M., Lukovsky, I., Solodun, O., Timokha, A. (2008):Natural sloshing frequencies in

    rigid truncated conical tanks.Engineering Computations, 25, Issue 6, 518-540

    15. Faltinsen, O.M., Rognebakke, O.F., Timokha, A.N. (2007): Two-dimensional resonant piston-like sloshing in

    a moonpool.Journal of Fluid Mechanics, 575, 359-397 [Supplementary material]

    16. Gavrilyuk, I., Lukovsky, I., Trotsenko, Yu., Timokha, A. (2007): Sloshing in a vertical circular cylindrical

    tank with an annular baffle. Part 2. Nonliear resonant waves.Journal of Engineering Mathematics, 57, 57-78

    17. Gavrilyuk, I., Lukovsky, I., Trotsenko, Yu., Timokha, A. (2006): Sloshing in a vertical circular cylindrical

    tank with an annular baffle. Part 1. Linear fundamental solutions.Journal of Engineering Mathematics, 54,

    71-88

    18. Faltinsen, O.M., Rognebakke, O.F., Timokha, A.N. (2006): Resonant three-dimensional nonlinear sloshing in

    a square-base basin. Part 3. Base ratio perturbations.Journal of Fluid Mechanics, 551, 93-116

    19. Faltinsen, O.M., Rognebakke, O.F., Timokha, A.N. (2006): Transient and steady-state amplitudes of resonantthree-dimensional sloshing in a square base tank with a finite fluid depth.Physics of Fluids, 18, Art. No.

    012103, 1-14

    20. Gavrilyuk, I.P., Lukovsky, I.A., Timokha, A.N. (2005): Linear and nonlinear sloshing in a circular conical

    tank.Fluid Dynamics Research, 37, 399-429

    21. Hermann, M., Timokha, A. (2005): Modal modelling of the nonlinear resonant sloshing in a rectangular tank

    I: A single-dominant model.Mathematical Models and Methods in Applied Sciences, 15, N 9, 1431-1458

    22. Faltinsen, O.M., Rognebakke, O.F., Timokha, A.N. (2005): Classification of three-dimensional nonlinear

    sloshing in a square-base tank with finite depth.Journal of Fluids and Structures, 20, Issue 1, 81-103

    23. Faltinsen, O.M., Rognebakke, O.F., Timokha, A.N. (2005): Resonant three-dimensional nonlinear sloshing

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    in a square base basin. Part 2. Effect of higher modes.Journal of Fluid Mechanics, 523, 199-218

    24. Faltinsen, O.M., Rognebakke, O.F., Timokha, A.N. (2003): Resonant three-dimensional nonlinear sloshing

    in a square base basin.Journal of Fluid Mechanics, 487, 1-42

    25. Faltinsen, O.M., Timokha, A.N. (2002):Asymptotic modal approximation of nonlinear resonant sloshing in a

    rectangular tank with small fluid depth.Journal of Fluid Mechanics, 470, 319-357

    26. Lukovsky, I.A., Timokha, A.N. (2002): Modal modeling of nonlinear sloshing in tanks with non-verticalwalls. Non-conformal mapping technique.International Journal of Fluid Mechanics Research, 29, Issue 2,

    216-242

    27. Gavrilyuk, I., Lukovsky, I.A., Timokha, A.N. (2001): Sloshing in a circular conical tank.Hybrid Methods in

    Engineering, 3, Issue 4, 322-378

    28. Faltinsen, O.M., Timokha, A.N. (2001):Adaptive multimodal approach to nonlinear sloshing in a rectangular

    tank.Journal of Fluid Mechanics, 432, 167-200

    29. Lukovsky, I.A., Timokha, A.N. (2001):Asymptotic and variational methods in nonlinear problems on

    interaction of surface waves with acoustic field.J. Applied Mathematics and Mechanics. 65, Issue 3, 477-485

    30. Faltinsen, O.M., Rognebakke, O.F., Lukovsky, I.A., Timokha, A.N. (2000): Multidimensional modal

    analysis of nonlinear sloshing in a rectangular tank with finite water depth.Journal of Fluid Mechanics,

    407, 201-234

    31. Gavrilyuk, I., Lukovsky, I.A., Timokha, A.N. (2000): A multimodal approach to nonlinear sloshing in a

    circular cylindrical tank.Hybrid Methods in Engineering, 2, Issue 4, 463-483

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