MESA

TTG 1 – Energy Efficiency Workshop, Sub Area 1.1 - Resistance

Brüsel, 5 March 2014

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MESA – SHIP RESISTANCE

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A motivation

Why to look into ship resistance?

• Emissions are directly coupled to energy consumption. • Up to 85% of all useful energy on board (exhaust and heat

losses already subtracted) is typically required to propel a ship and hence related to Hydrodynamics.

• Savings in this place will benefit the whole ship energy household.

• Each kW saved to propel a ship means less fuel consumption.

• … and each ton of fuel saved means 3.7ts of CO2 not emitted (+ other emissions).

• Drag/Resistance plays an important role.

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Resistance - Structure

• Two major contributions: – Pressure related – Viscosity related

• Often different “decomposition” in naval architecture context.

• Resistance should be reduced. • To do this, we must understand how resistance

components work, we need to be able to model and predict them and find ways to influence them.

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Resistance – Decomposition in MESA

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1 Ship Resistance

Calm water Categorie

1.1 Pressure related resistance (form) Tools/ Design

1.2 Viscous resistance (friction) Tools and (surface) technologies

Operational conditions

1.3 Added resistance in seaways Tools / Design

1.4 Aerodynamic resistance Tools / Design

Pressure / Form Resistance 1 Ship resistance 1.1 Form resistance Technologies to predict and improve form resistance 1.1.0 general considerations, naval architecture good

practice 1.1.1 traditional model testing 1.1.2 Empirical / statistical methods 1.1.3 Theoretical prediction methods 1.1.3.0 analytical methods 1.1.3.1 (non-linear) potential flow codes, 1.1.3.2 RANS codes, w and w/o free surface effects, 1.1.3.3 adjoint methods 1.1.4 (CFD based) Optimisation

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Viscous Resistance

1 Ship resistance 1.2 Frictional Resistance 1.2.1 General Prediction 1.2.1.1 ITTC 57 line 1.2.1.2 alternative friction lines 1.2.1.3 Numerical prediction 1.2.2 Surface roughness 1.2.2.1 Measurement techniques 1.2.2.2 Computational approach 1.2.2.3 Fouling 1.2.3 Technologies to influence frictional resistance 1.2.3.1 Coatings / Antifoulings 1.2.3.2 Air lubrication 1.2.3.3 Boundary layer stabilisation

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Hull pressure: Smooth / rough

Added Resistance in Seaways

1 Ship resistance 1.3 Added resistance in

seaways Technologies to predict and improve added resistance

1.3.0 general considerations, naval architecture good practice

1.3.1 model test 1.3.2 Seakeeping codes 1.3.2.1 based on (non-linear) strip theory 1.3.2.2 3-d panel codes 1.3.2.3 RANS codes 1.3.3 Form optimisation for resistance in seaways 1.3.4 Additional resistance from yawing in a seaway

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Aerodynamic Resistance

1 Ship resistance 1.4 Wind resistance Technologies to predict and improve aerodynamic

resistance 1.4.0 model tests 1.4.1 statistical methods 1.4.2 computational methods / CFD

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Operational Influence on Resistance

• Trim optimisation is hydrodynamically relevant as it influences the resistance of a vessel.

• These aspects have been investigated in several projects and are today common practice.

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Example line of successful developments

FP7

STREAMLINE

GOALDS

TARGETS

GRIP

EUROVIP

MARNET-CFD

FANTASTIC

OPTIPOD

EROCAV

FP5 FP6

SAFEDOR

VIRTUE

Name: STREAMLINE Start: 03/2010 End: 02/2014 Goals: Simulation of complex propulsor flows, optimisation of multi stage and large area propulsors Open Issues: Project still running

Name: MARNET-CFD Start: 11/1999 End: 03/2003 Goals: CFD state-of-the-art assessment Open Issues: General accuracy aspects of CFD simulations

Name: FANTASTIC Start: 04/2000 End: 03/2003 Goals: Hullform optimisation / wave resistance – based on panel codes Open Issues: Lack of accuracy of CFD simulations

Name: OPTIPOD Start: 01/2000 End: 12/2002 Goals: Pod propeller design guidelines Open Issues: Systematic studies for higher speeds, design of pod casings

Name: EROCAV Start: 01/2001 End: 12/2003 Goals: Cavitation analysis and tools Open Issues: Cavitation and materials, tools to predict long term effects of cavitation

Name: SAFEDOR Start: 08/2005 End: 02/2009 Goals: Establish risk based safety assessment and develop tools for design integration. Open Issues: Systematic analysis of flooding damages and tools for prediction missing

Name: GOALDS Start: 09/2009 End: 08/2012 Goals: Enhanced survivability of passenger vessels and RoPAX w.r.t. flooding Open Issues: Project still running

Name: GRIP Start: xx/2011 End: xx/2014 Goals: Propulsion improvement and devices for retro-fit Project not yet started

Name: EUROVIP Start: xx/2011 End: xx/2014 Goals: Open Issues: Project still running

Name: TARGETS Start: 12/2010 End: 11/2013 Goals: Development of advanced CFD methods for operational conditions and integration into a global Dynamic energy Management model for a ship Open Issues: Project still running

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Name: VIRTUE Start: 01/2005 End: 05/2009 Goals: Improvement of CFD codes (accuracy), improved optimisation, CFD tools for a wide range of maritime hydrodynamics applications, integration of distributed analysis tools Open Issues: Improved full scaled predictions, complex propulsor flows, added resistance in a seaway.

Relevant EU Projects (identified so far)

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• CALYPSO • FANTASTIC • VIRTUE • EFFORT, • STREAMLINE, • TARGETS, • GRIP • SMOOTH • SHOPERA

Catalogue - Spreadsheet

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Link: Spreadsheet

To do:

• Identification of other major FP 6/7 projects, • Short description of contents, • (details often difficult to obtain, public reports

are sometimes not very comprehensive).

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Next Steps

• Definition of (technology) gaps: <= TTG, technology driven.

• Definition of Research needs: <= Strategy Group, market driven.

• Balancing of needs and gaps – based on assessment of technology potential.

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Technology Gaps / Needs (I) identified in TTG 1.1

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Viscous resistance. • Importance of viscous resistance is further pronounced for

slow steaming conditions. • The physical properties of water [ν (t, ρ)]can hardly be

influenced. • … but the quality / smoothness of the surface and its

condition (fouling) can be influenced technically. • New coatings promise superior quality and reduced

frictional resistance. • High Reynolds number tests indicate some potential of

several coatings and even patterned surfaces (riblets). • Tangible data / data base are missing.

Technology Gaps / Needs (II) identified in TTG 1.1

Better prediction of added resistance in waves. • Need for fw factor in EEDI formulation, • Present guidelines are vague: “fw to be

determined by conducting ship specific simulations or based on guidelines - (Guidelines will be developed)“

• Present Tools (potential flow) are dubious, model test find that added resistance for λ/L < 0.8 are not useful.

• Full RANS is (presently) to time consuming.

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