Fluid transients and FSI

Arris Tijsseling

TU Eindhoven

The Netherlands

water hammer:

c ≈ 1000 m/s

V

Δ = ΔP c V

P {

}+P

large force on valve: 2 Δ2

P πR

Manuel, 1968Wijdieks, 1983

2P ≈ 20 barV ≈ 1 m/s

Joukowsky

pipe bridge

Almeida & Koelle, 1992

waterhammer forces on pipe bridge (FSI)

waterhammerinitiated 5 km downstream

FSITijsseling & Lavooij, JFS 1990

news paper

Almeida & Koelle, 1992

FSIPoisson coupling

radial motion of the pipe wall

hoop

RP

e

pipe cross sectionpipe radius

wall thickness

R

e

FSIjunction coupling

axial motion of the pipe wall

axial end2

RP

e

free closed pipe end zV u &

FSI test problem

L = 20 m, R = 0.4 m, e1/R = 0.04, e2/R = 0.02

thick section

Tijsseling, PVP-2009

calculated pressure at PT forinstantaneous valve closure

0 0.02 0.04 0.061.5 10

6

0

1.5 106

time (s)

pre

ssu

re (

Pa)

noise?

calculated axial pipe stress at PT forinstantaneous valve closure

0 0.02 0.04 0.065 10

7

0

5 107

time (s)

axia

l st

ress

(P

a)

pipe-wall

acoustics

Skalak’s wave-front problem

highpressure

Skalak, 1956

Skalak’s solution (wave front)

wave front dispersion (dimensionless)

30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 2 4 60.4

0.2

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

dimensionless distance from wave front

dim

ensi

onle

ss w

ave h

eig

ht

Joukowsky

Tijsseling et al, JSV 2008

Rock-bored tunnels

Hachem and Schleiss,JFS 2011

Underground hydraulic networks

Stephens et al,JHE 2011

Laboratory set-up (Vogelaar, TU Eindhoven)

Clerkenwell Tunnel flood - LondonJanuary 2015

Network Rail sends Thames Water

'multi-million pound bill'

• Network Rail has issued Thames Water

with a "multi-million pound bill" after leaks

and a burst water main led to more than

1,000 trains being cancelled.

• "We believe this problem was first

identified as far back as 2007, and the

problems with water on the track have been

caused by a lack of maintenance on their

part."

• Thames Water identified a burst water main

on Friday evening and found a further four

leaks that are yet to be fixed.

• Specialist teams are also carrying out

assessments of the pipe and checking roads

nearby for additional leaks.