Fliud-solid interactions

Week 1. Основы

W1-1. Связь механики жидкости и механики твердого тела

solid mechanic

fluid mechanic

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FLUID AND SOLID MECHANICS
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A FUNDAMENTAL ISSUE
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COUPLED FLUID AND SOLID MECHANICS
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FLUID-SOLID INTERACTIONS
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W1-2 Инструмент анализа размерностей

FLOW AROUND A SPHERE : DIMENSIONAL QUANTITIES
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FLOW AROUND A SPHERE : THE DIMENSIONLESS REYNOLDS NUMBER
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PHYSICAL LAWS
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EXAMPLE : DRAG ON A SPHERE
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MEANING OF DIMENSIONLESS PARAMETERS
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W1-3 Безразмерные числа

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FLUID ALONE
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SOLID ALONE
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STIFFNESS AND DENSITY
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DECOUPLED FLUID-SOLID INTERACTIONS
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W1-4 Размерный анализ взаимодействий

DIMENSIONLESS PARAMETERS
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FLUID AND SOLID
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A NEW DIMENSIONLESS QUANTITY
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THE MASS NUMBER
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THE REDUCED VELOCITY
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THE CAUCHY NUMBER
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CLASSIFYING PROBLEMS USING DIMENSIONLESS NUMBERS

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W1-5 Объединенные уравнения для жидкостей и твердых тел

EQUATIONS IN THE FLUID DOMAI
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EQUATIONS IN THE SOLID DOMAIN
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SINGLE MODE APPROXIMATION IN THE SOLID DOMAIN
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FLUID AND SOLID
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AT THE INTERFACE
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Kinematic condition
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Dynamic condition
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AT THE INTERFACE
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Fluid boundary
conditions
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Solid boundary conditions
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W1-6 Безразмерные уравнения сопряжения

DIMENSIONLESS QUANTITIES IN THE FLUID
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DIMENSIONLESS QUANTITIES IN THE SOLID
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DIMENSIONLESS TIME
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DIMENSIONLESS EQUATIONS AT THE INFERFACE

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Kinematic conditio

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Dynamic condition

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Fluid boundary
conditions
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Solid boundary
conditions
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Week 2. Твердое тело с неподвижной жидкостью

W2-1 Небольшие пониженные скорости

EFFECT OF THE REDUCED VELOCITY
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BOUNDARY CONDITIONS ON THE FLUID DOMAIN
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SMALL REDUCED VELOCITY
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GENERAL CASE

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COUPLING WITH A STILL FLUID

Fast

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Slow

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W2-2. Адаптированные безразмерные числа

NEW DIMENSIONLESS NUMBERS

Reynolds
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Froude
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Cauch
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Stokes
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Dynamic Froude
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Mass
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CHOICE OF DIMENSIONLESS NUMBERS

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DIMENSIONLESS VARIABLES
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FLUID AND SOLID
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Fluid boundary
conditions
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Solid boundary
conditions
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Boyndary conditions
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W2-3. Малое движение твердого тела

Displacement number
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EXPANSION OF ALL VARIABLES
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EQUATIONS AT THE ORDER ZERO IN D
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Hydrostatics !
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Kinematic condition
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Dynamic condition
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EQUATIONS AT THE INTERFACE
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f{M[-PI+1/St(nablU+nabl't'U)]n}phidS=Df

Pure interface
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Mphi_f[-PI+1/St(nablU+nabl't'U)]n_dS=D*f

P(X_+Dqphi)=P0(X+Dqphi)+Dp(X+Dqphi)+...
=P0(X_)+Dqphi_nablP0+Dp(X)+...

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TWO KINDS OF FORCES

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u= qd/dtphi _
Mfphi
[-pI+1/St(nablu+nabl't'u)]ndS-Mqf(nablPphi)(phin)dS=f

W2-4.Добавленная жесткость

SMALL REDUCED VELOCITY, SMALL MOTION
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Mfphi_[...]n_dS-Mqf(nablP0phi)(phin)dS=f


M - mass number
q - Modal displacement
P0 - static pressure
(nablP0phi)(phin)dS - modal shape
phin_ - Geometry

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FLUID-INDUCED STIFFNESS
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EXAMPLE : ICEBERGS AND ICE CUBES

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Linearized fluid dynamics
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Hydrostatics

W2-5. Добавленная масса

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FLUID AND SOLID
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FLUID LOADING : MOTION INDUCED STRESS

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Fluid boundary
conditions
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Boundary conditions
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STOKES NUMBER
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HIGH STOKES NUMBER
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Negligible viscous effects

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HIGH STOKES NUMBER : A SINGLE MODE SOLUTION
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ADDED MASS
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The fluid response is instantaneous
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The fluid force is an inertia force.

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Initial choice
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New choice
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Small reduced velocity
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Small amplitude
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Small viscosity
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W2-6.Вычисление добавленной массы

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Added mass
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A CYLINDER IMMERSED IN AN INFINITE FLUID DOMAIN
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Dimensionless
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Dimensional
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Apparent mass ~ double mass
(in that case !)

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KINETIC ENERGY OF THE FLUID
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DIRECTIONAL ADDED MASS
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W3 Вязкость и гравитационный эффект

W3.1 Добавленное демпфирование

FLUID AND SOLID
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Solid boundary
conditions
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Fluid boundary
conditions
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STOKES NUMBER
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LOW STOKES NUMBER
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Dominant viscous effects
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LOW STOKES NUMBER :
A SINGLE MODE SOLUTION
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interface

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ADDED DAMPING
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The fluid force is a damping force
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The fluid response is instantaneous
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ADDED DAMPING AND ADDED MASS
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Added mass effect
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Added damping effect
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