Ocean Engineering Model Test at Harbin Engineering · PDF fileignored for the FPSO preliminary design because of ... Test the pitch,roll,heave and acceleration response of the ship

June 2015

Liping Sun

Ocean Engineering Model Test at Harbin Engineering University

1. Introduction to DERC

2. Deepwater Offshore Basin in the World

3. Platform Motion Model Test

4. Riser Model Test

Outline

The Deepwater Engineering Research Center (DERC)

was established at HEU in the end of 2005.

In 2006 DERC got funding from Chinese Education

Ministry and Foreign Expert Bureau to build “Base on

Science and Technology of Deepwater Engineering ”

An active team of 15 foreign members and 15

internal members has been established.

Domestic members are from HEU whose major in

various NA&ME such as hydrodynamics, structure ,

CFD and so on.

Deepwater Engineering Research Center

Academic Master

Foreign Team Members

Motion response of floating structures

Nonlinear water wave theory

Rod DynamicsSome team members

Prof. William C. Webster

USA

Domestic faculty members keep contacts with overseas members through a variety of ways.

Establish relations of cooperation with MARINTEK、LabOceano、OTRC。

Establish relations of cooperation with Univ. and Classification Society such as Univ. of California , Berkeley, Univ. of Michigan, Texas A&M Univ., Osaka Univ.、BV、GL and so on。

International cooperation in scientific research project 。

International Exchange and Cooperation

International Conferences


2. Deepwater Offshore Basin in the

World


4. Riser Model Test

Outline

MARIN Basin in Netherlands

Built in 2000，main dimensions 45m× 36m ×10.5m, pit:5mX 30m

Simulate wind, wave and current; on the 10.5m depth there is six layers

pipe to simulate shear current

Carriage moves in both X and Y direction，max. speed 3.2 m/s

MARINTEK Basin( Norwegian Marine Technology Research Institute)

Main dimensions: 80m×50m×10mEnvironmental simulation

including wind, wave and

current;

Maximum current velocity

approx. 0.2 m/s at 5 m water

depth.

The carriage system speed up

to 5 m/s.

Multiflap wave maker:

Regular waves: Maximum wave height: 0.4 m.

Wave periods: 0.6 s and above

Double flap wave maker:

Regular waves. Maximum wave height: 0.9 m.

Wave periods: 0.8 s and above.

LabOceano Basin

in Brazil

Main Dimensions: 40mX30mX15m，Pit:5mX15mSimulate wind, wave and

current

Wave period：0.5 – 5.0 s；Max.regular wave height:0.5m；Max. wind velocity:12m/s

Main dimensions:150ft*100ft*19ft，Pit:55ftSimulate wind, wave

and current

OTRC Basin(Offshore Technology Research Center)

Shanghai Jiaotong Univ.Basin

Main dimensions:50mX40mX11.5m，Pit: 5mX40m。

Wind, current, wave simulation

X,Y carriage, max. velocity 3m/s

Wave :3-D multiflaps wavemaker

Maximum significant wave

height :0.3m

Current max. velocity:0.1m/s

Main dimensions:50mX30mX10m

50m x 30m x 10m Wind, current, wave simulation

X,Y carriage, max. velocity 3m/s

Wave :3-D multiflaps wavemaker

Regular, irregular waves in arbitrary

direction

Maximum wave height :0.3m

Current Velocity:0.1m/s ～0.5m/s

HEU Deepwater Basin

Towing Tank

110m × 7m × 3.5m

Model Length: 1.8 - 4.0m

2D & 3D Regular and

Irregular Waves

Max. Wave Height: 0.4m

Wave Periods : 0.4 - 4.0sec.

Max. carriage velocity:6.5m/s


2. Offshore Basin in the World


4. Riser Model Test

Outline

To demonstrate proof of concept

To verify design assumptions, factors and

allowances

Substantiate analytical technique

Problem difficult to handle analytically

To obtain empirical coefficients

To verify offshore operation

To validate the numerical model and design

analysis tools

To independently confirm the accuracy of

hydrodynamic performance of a particular design

The Purpose of Model Test

Size of model & facility -- depth limitation

Physical size of the basin requires mooring line

truncation. For a deepwater system of 3000m, the

deepest basin(15m) can only model the whole system

using a scale of about 1:200 which is far too small

Environment generation(e.g. current turbulence)

Instruments -- measurement accuracy

The number of test cases are limited

Scale distortion

catenary mooring & taut lines; risers & tendons

Model Tests Considerations

DEEPWATER MODEL TEST HYBRID APPROACH

LINE TRUNCATION CONSIDERATIONS

Numerical Simulation and Model Test Study of FPSO and CALM System

Verify the experiment schemesBy doing coupling analysis in time

domain under same load condition

to compare the results between the

model system and original system.

FPSO model test scheme（1：90） CALM system test scheme（1：40）

Model Test Scheme Design

Top tension of mooring line vs displacement Horizontal tension of mooring line vs displacement

The static characteristics of calm mooring

system before and after truncation are

equivalent.

The dynamic characteristics are similar.

Verify the truncation design of CALM mooring system

（1）The coupling of CALM motion to FPSO can be

ignored for the FPSO preliminary design because of

the far distance of two bodies.

（2） The coupling effect of FPSO and OOL(Oil

Offloading Line) must be considered in the analysis of

FPSO's response because the top tension of the OOL

and the mooring line of FPSO have the same order of

magnitude.

（3）The influence of the FHSR on the movement

and the force of the FPSO system is minimal. It’s

influences on FPSO can be ignored.

Results

（4）Under West Africa environment FPSO’s motion is

controlled by Squall . So it’s the ultimate condition for the

FPSO strength check.

（5）The OOL is strongly influenced by the CALM

because the pipeline weight and the drainage volume of

buoy have the same order of magnitude.

（6） Plane motion of shuttle tanker will increase the

motion amplitude of the CALM buoy. But for the ultimate

strength check there is no need to consider effect of the

shuttle tanker because oil external operation usually

done in mild environment.

Study on multi-body Interaction during transportation and installation

Study on multi-body interaction during lifting

Analysis of vertical relative motion and safety during lifting

Analysis of safety and relative motion between two bodies during in place

Test of multi-body Response

Test scale: 1:60

Lifting test In-Place test

• The experimental purpose is to verify the numerical analysis model of

multi floating bodies.

multi-body system including,

• SPAR tank

• crane ship

• upper module

In the stage of in-place operation

多浮体-运输船-201.rmvb

多浮体-运输船-201.rmvb

Some safe operation environmental

conditions are suggested.

The maximum significant wave height

is suggested to be less than 2.0m

both for the lifting and in-place

operation。

Study on the Global Performance and Model Test of Crane and

Pipelaying Vessel

• Study on Seakeeping Performance in Operation Condition

• Hydrodynamic Analysis consider Coupling between Pipe and Ship

in Pipelaying Condition

• Stability Ananlysis

• Hydrodynamic Model Test of the Vessel

• Catenary Pipeline Load Analysis

Development of Large Crane and Pipelaying Vessel

for 3000m Waterdepth

1、Max. Wind and Wave 2、Wind and Swell 3、Standby Condition

Wind Velocity：16m/s； Wind Velocity：8m/s； Wind Velocity ：26m/s；

Wave height：Hs=2.5m Wave height：Hs=2.0m Wave height：Hs=8.2m

Wave period：Tp=6.0~9.0s

Wave period：Tp=10.0~12.0s

Wave period：Tp=11~15s

Current Velocity：2.0 knot Current Velocity：2.0 knot Current Velocity：3.0 knot

Jonswap Spectrum Jonswap Spectrum Jonswap Spectrum

Environmental Conditions

model for shallow water

model for deepwater

Test scale: 1:50

Test the pitch,roll,heave and acceleration

response of the ship under dynamic positioning

condition.

Wave direction 180 degrees,

the self-propelled condition

Wave direction 165 degrees, 50%

pipelaying, shallow water condition

Motion Test in Operation Condition

1）In the beam condition the heave is significant . So it should be avoided

to lay pipe in this condition.

2）During pipelaying the roll motion is less in deepwater than in shallow

water.

3） During pipelaying the pitch and heave amplitude are biggest in 150

degrees wave direction. But there is no big difference both in deepwater

and in shallow water.

4）The vertical acceleration of the stinger bottom changes most. Followed

by the position connected with ship. The smallest position is at the

midship.

Overall scheme of DP for a

deepwater Semi

Capability analysis of DP system

Control system design of DP system

Simulation of DP control system

Developed a dynamic positioning

simulation system of semi drilling

platform

Dynamic Positioning Study of a Deepwater Semisubmersible

SEMI model test on DP control system

The purpose is to verify the DP control system can make sure the surge、sway and yaw of the SEMI to satisfy the DP3 requirements under wind，wave and current conditions when the thrusters work normally or two thrusters failed.

load ParameterStandby Condition Operation Condition

SEMI 981 model SEMI 981 model

Wave

SpectrumISSC

Spectrum

ISSC

Spectrum

ISSC

Spectrum

ISSC

Spectrum

Hs(m) 6 0.12 6 0.12

Tp(s) 11.2 1.58 11.2 1.58

Ts(s) 9.5 1.34 9.5 1.34

WindVelocity

（m/min）25.7 3.67 23.2 3.28

CurrentVelocity

（m/s）1.03 0.146 0.93 0.132

模型试验的海洋环境条件

Load Conditions

SurgeSway Yaw

Test Results

Thrust Curve

Model Test of FPSO in Enping Field

Do model test for two different shape FPSOs to compare the influences on damping, motion and mooring line response and to provide suggestions for the design。

No. Environment condition

Wind

speed

（m/s）

waveCurrent

（m/s）Hs

（m）

Tp

（s）

1 Full load500years wave，wind,wave,current in the

same direction5.94 0.24 1.96 0.299

2 Full load500years wave，wind,wave in the 0

direction ,current in 45 direction5.94 0.24 1.96 0.299

3 Full load500years wave，wind,wave in the 0


4 Full loadMonsoon, 500years, wind,wave,current in

the same direction3.23 0.14 1.67 0.192

5 Full loadMonsoon, 500years, wind,wave in the 0


6 Ballast500years wave，wind,wave,current in the

same direction5.94 0.24 1.96 0.299

7 Ballast500years wave，wind,wave in the 0


8 Ballast500years wave，wind,wave in the 0


9 BallastMonsoon, 1 in 500years, wind,wave in the 0


Test Results

There is visible green water under both ballast and full load conditions.

The green water is much for the full load condition than ballast condition. When current and wave in different direction the green water is obvious at the midship.

By increasing the height of forecastle there is no green water anymore on the bow but there is no any change at the midship.

Model Test of SSCV H206

Series of model tests were carried out in HEU basin to get the motion response, air gap of SSCV H206 under different conditions.

Irregular Wave Conditions

15 wave probes were set on SSCV to get the air gaps of different

positions. Three load conditions:

Survival condition: HS=12m, Tp=13.7s, gamma=3.33;

Survival condition: HS=10.42m, Tp=11.18s, gamma=3.33;

Towing condition: HS=3m, Tp=9.83s, gamma=3.33

Video of SSCV in 45°wave direction

under survival conditionSlamming on SSCV in 45°wave direction

The response under survival conditions was severe, the air gap was 0cm, and

obvious slamming was found on the lower deck.


2. Offshore Basin in the World


4. Riser Model Test

Outline

Design and Analysis of FSHR

1. Global design of Free Standing

Hybrid Riser

2. Global Strength Analysis

3. Fatigue Analysis

4. Design of Buoyance Can

5. Sensitivity Parameters Analysis

Three kinds of VIV suppression devices are tested, uniform current from 0.2m/s～0.6m/s，interval 0.1m/s。

Vortex-induced vibration suppression device model test

Without suppression device, the biggest amplitude appeared under current velocity of 0.2 ~ 0.3 m/s ,which is the lock area, when the velocity is greater than 0.4 m/s, amplitude decreases.

With suppression device ，it was founded the double set of double helix work best ，a single set of double helix is the second，fiber is the last。

Experimental results

水池

圆柱体

连接板

水平导轨

滑车

垂向运动机构

横向电位器

加速度传感器

弹簧

滚珠轴承

■ Φ20×120cm

■ Φ11×120cm

■ Φ 5×120cm

圆柱体

水平导轨

连接板

顺流向电位器滑车

卡块

水池

垂向运动机构

滚珠轴承

测桥

固定架

Model test study on double degree of freedom VIV of cylinder

Cylinder motion trajectories results

Cylinder motion trajectories corresponding to different natural

vibration frequencies are completely different.

That is, they respectively appear to be “D” shape, “egg” shape,

“rain drop” shape and figure “8” shape.


When fx / fy is large, the cylinder

appears to have a “D”-shape

trajectory.

When the natural vibration

frequency ratio fx / fy is reduced

to the lowest value 0.474, at the

tip of the motion trajectory, i.e.,

the lower half of “8”-shape

trajectory, gradually appears.


with a decrease of fx / fy, the

original “egg”-shape

trajectory gradually changes.

At the tip of the motion

trajectory of the cylinder,

another tight loop appears

and grows, leading to the

beginnings of “8”-shape

trajectory forms.


The “rain drop” forms a tight loop at the tip. The tight loop at the upper end becomes larger and finally resulting in an oblique figure “8”-shape.

Different fx , fy and Ur are the main causes of the various changes in the form of the cylinder VIV trajectory.

Two cylinders VIV test

Test Matrix

ExpNo.

Spacing(spacing ratio)

Velocity (m/s)

0.2 0.3 0.4 0.5 0.6 0.7 0.8

160.5 cm

(L/D=5.5)√ √ √ √ √ √ √

254.2 cm

(L/D =4.9)√ √ √ √ √ √ √

339.3 cm

(L/D =3.6)√ √ √ √ √ √ √

432.5 cm

(L/D =3.0)√ √ √ √ √ √ √

arrangement Spacing (spacing ratio)

side by side arrangement

absolute value（cm） 51.6 46.6 42.4 38.3 33.5 29.0

spacing ratioT/D 4.7 4.2 3.9 3.5 3.0 2.6

Two cylinders in tandem arrangement

A new amplitude reaction format totally different from single cylinders VIV reaction was found.

Amplitude results

When the spacing ratio of two cylinders in tandem arrangement

is large enough, there is no influence between two cylinders.

Amplitude results

When the two cylinders’ spacing ratio is less than the critical value, the “dual-peaks” phenomenon appears with the cross flow vibration of the left and right cylinders.

Thank you for your attention

Documents

Ocean Engineering Model Test at Harbin Engineering · PDF fileignored for the FPSO preliminary design because of ... Test the pitch,roll,heave and acceleration response of the ship