PROJECT and MASTER THESES 2015/2016

 

Below you’ll find proposed topics for project and master theses. Most of the proposed topics are just sketches. The detailed topics will be made in discussion between student and supervisor.

 

Most topics can be both project and master thesis. It is most common to have the same main topic for both project and master. Several of the topics might even be continued in a PhD project. Some of the topics are related to ongoing research in the department, others have been proposed by industry or by MARINTEK.

 

This list is made by Sverre Steen, http://folk.ntnu.no/sverres

 

Overview of proposed topics. A more detailed description follows on the next pages.

 

·       Development and testing of a novel, energy-saving bow for slow ships

·       Steering and thrust loss while trawling

·       Identification of the benefits of more accurate course and position measurement in ship operations

·       Posisjoneringsevne og optimal orientering av fartøy i bi-modale bølgespekter.

·       Optimalisering av form på akterskip for offshorefartøy

 

 

 

 

 

Use of CFD to compute added resistance due to waves

It is important to be able to compute the added resistance due to waves on a ship for many reasons, such as calculation of sea margin and dimensioning of propulsion system, optimization of hull form for performance in a seaway, routing studies and much more. Current simplified methods, like the ones found in the ShipX package, give fairly reliable estimates in head seas, but they don’t take the above-water geometry into account, making proper hull optimization studies impossible, and they aren’t very reliable in following waves. URANS CFD methods give generally better results, but they are very resource-intensive, and not practically applicable for irregular waves, due to extremely long computation time. In this Msc-thesis the plan is to explore the use of URANS CFD for calculation of added resistance, but without taking viscous effects into account, so that course grids can be applied, so that the computational time can be much reduced. At the same time, the fully non-linear free-surface treatment of the Volume of Fluid method is used. Suggested CFD software is Star CCM+, but other softwares might also be used.

 

Proposed by: NTNU

Supervisor: Sverre Steen. Advisors: Jarle A. Kramer

 

Development of efficient testing methods with documented uncertainty

Experimental validation of performance of marine structures, such as ships, propellers, offshore structures and fish farms are an essential part of the development projects. Most of the experimental validation is performed in model scale. It is of course essential to know the accuracy of the results of experimental validation. Such tests are also quite costly, so one tries to make the tests as quickly and efficiently as possible. There is a trade-off between accuracy and efficiency. As an example, the waiting time between runs in a towing tank impacts the accuracy – if the waiting time is too short the remaining waves and current in the tank will influence the results of the next run. Another example is the length of the time series used to find mean values and/or other statistical parameters like standard deviations. The longer time series the better accuracy, but increased time and therefore cost. Other was to increase efficiency is to perform the tests in different way. It has for instance been proposed to test at slowly, but continuously increased speed rather than at different constant speeds. Here at the Marine Technology Centre, the development of new testing procedures has become more urgent since MARINTEK is introducing automatic control of the towing carriage and experiment procedure. There are also new developments in methodology to link measurement uncertainty to the length of the time series. This forms the background for a proposed project and master thesis to study development of efficient testing methods with documented uncertainty. There is great freedom to select focus in this project – as the introduction shows there are several possible topics that can be focused on.

 

Supervisor: Prof. Sverre Steen. Advisors: Kjetil Berget, Bjørn Ola Berge

 

 

Accuracy of propeller design methods

 

There are many different propeller design methods, with different levels of complexity, like lifting line, vortex-lattice lifting surface, and panel methods. There are also different software where these theories have been implemented. The idea is to investigate the difference in obtained propeller design using different methods and softwares. The plan is for the student to make his own lifting line design program, and then to use OpenProp and AKPD in addition, and use these different softwares to design a limited number of different propellers, and compare the resulting optimum designs. Furthermore, the resulting designs shall be evaluated by the panel method AKPA, as well as using CFD. The objective is to give recommendations regarding what is suitable propeller design software.

Proposed by: Luca Savio, MARINTEK.

Supervisor: Sverre Steen. Advisors: Luca Savio, Erik Lehn.

 

 

Rulledempning ved bruk av tunnellthrustere og azimuth-thrustere

Bakgrunn: Rulledempning av skip som ligger stille er i dag basert på slingrekjøler og i noen tilfeller rulledempningstanker. Både for yachter og offshore-fartøyer (for eksempel stand-by fartøyer) er det stor interesse for reduksjon av rullebevegelser når fartøyer ligger stille. Slike fartøyer er som regel utstyrt med tunnell-thrustere, og i en del tilfeller også med azimuth-thrustere. Thrusterne benyttes gjerne til Dynamisk Posisjonering (DP). Det er mulig å samtidig benytte dem til å dempe rullebevegelsene, fordi DP-systemet arbeider mot saktevarierende driftkrefter, som har en annen periode enn rulleperioden.

Prosjekt: Studere tilsvarende systemer for rulledempning av skip ved bruk av ror, samt annen relevant litteratur. Gjøre beregninger av nødvendig thrustkraft og dempe-effekt.  

Master: Lage en beregningsmodell som inkluderer tapseffekter og dynamiske effekter. Lage et enkelt kontrollsystem for styring av thrusterne. Gjøre simuleringsstudier. Om man på grunnlag av prosjektoppgaven finner det hensiktsmessig kan det gjennomføres modellforsøk med systemet.  

Forslagstiller: NTNU. Oppgaven vil inngå i University Technology Centre, som drives i samarbeid med Rolls-Royce.

Faglærer: Sverre Steen

 

 

Development and testing of a novel, energy-saving bow for slow ships

 

Background: Large, slow ships, like most large bulk and tank vessels, have very blunt bows. They are designed this way to maximize the cargo-carrying capacity within the main dimensions, and because it doesn’t increase the calm water resistance very much. However, it is found that blunt bows increase the added resistance in head waves, and especially for relatively short waves, the effect of a blunt bow is very negative. Therefore, it is suggested to develop an add-on bow that reduces the added resistance. There are also suggestions for how this bow can be designed so that it reduces the pitch motions of the ship.

Project thesis:

In addition to a literature survey, a case vessel will be selected and preliminary calculations of added resistance and ship motions will be performed, including calculations with the suggested bow extension.

Master thesis:

Design of an improved bow extension. Design and evaluation of the motion-damping system. It is foreseen that model tests will be required for proper evaluation of the proposed bow extension.

Proposed by: NTNU..

Supervisor: Prof. Sverre Steen.

 

 

Steering and thrust loss while trawling.

From practical experience, it is found that a large part of the propeller thrust is lost due to excessive use of rudder to maintain direction of the trawler while trawling. The use of rudder is necessary to keep wanted heading and track, which is offset due to environmental forces (wind, waves, current). Like for a tug, the forces in the tow lines are important for the control of the trawler while trawling. Although the magnitude of the forces are mainly given, the point of application on the ship might be changed to improve the control of the ship. The trawler “Prestfjord” has recently had an extensive measurement package installed – unique to such a ship. These measurement results will be made available to the candidate as an important resource in the project. The measurements are performed as part of the SITNEF-project Improvedo: http://www.sintef.no/Fiskeri-og-Havbruk-AS/Prosjekter/2010/Improvedo-Improved-vessel-design-and-operation/

Suggested activities in the project and master:

 

Topic proposed by Rolls-Royce Marine (Leif Vartdal)

Supervisor: Prof. Sverre Steen.

 

Identification of the benefits of more accurate course and position measurement in ship operations

Fugro is developing the On-board decision support system Marinestar, which is based on accurate logging of position fore and aft (including elevation!) using GNSS. The extreme accuracy of about 1 cm enables optimization of for instance trim, and it is also found that a more precise and stable heading measurement might reduce the use of rudder, and thereby reduce the fuel consumption. Fugro has installations of Marinestar on some vessels, where data from full scale are available.

The objective of this project and master thesis is to evaluate the benefit of having a more accurate compass course for the auto-pilot. Also other aspects of the performance of the system could be included.

 

Proposed by: Arne Norum, Fugro

Supervisor: Prof. Sverre Steen

 

Posisjoneringsevne og optimal orientering av fartøy i bi-modale bølgespekter.

Mange DP operasjoner har begrensninger ved Hs 2-4 men både retningsavvik mellom vind og bølger samt karakteristikken til bølgeretningsspekteret (energi som funksjon av retning og frekvens) for dønning og vindsjø har betydning for operabiliteten.

RRM har dokumentasjon på bølgeklima i ulike havområde m.h.t. forekomst av sammensatte bølgesystem.  For Hs 2-4 meter (total signifikant Hs), viser undersøkelsen at Ekofisk, Haltebanken og Foinhaven har to identifiserbare og ”likeverdige” bølgesystem i sine retningsspekter i hhv. 31, 89 og 45 prosent av tida (en kan anta at Haltenbanken er representativ for områder i Norskehavet lenger nord som også er eksponert for dønning fra Atlanterhavet).

 

I denne oppgava er det tenkt at station keeping egenskaper skal studerast med basis i tilsvarende bølgestatistikk. Her kan vi tenke oss at MULDIF kan bli anvendt i M.Sc delen (sjå for øvrig separat aktivitetsbeskrivelse for Marintek delprosjekt for implementering og testing av MULDIF i ShipX).

 

Oppgave foreslått av Leif Vartdal, Rolls-Royce Marine AS

Hovedveileder: Prof. Sverre Steen. Medveileder: Dariusz Fathi (MARINTEK)

 

 

 

Optimalisering av form på akterskip for offshorefartøy

 

Offshorefartøy er utstyrt med en hekk med gankse dyp V-form, for å unngå slamming i akterskipet. Dette fører til et stort neddykket tverrhekk-areal (se bilde under), som igjen medfører betydelig økt motstand. Spørsmålene som ønskes belyst i oppgaven er:

Hvor mye motstand ligger egentlig i denne dype tverrhekken?

Hvor dyp trenger V-formen å være for å unngå kritiske slamming-laster?

Kan man gjøre andre tiltak enn bruk av dyp V-form for å unngå problem med slamming-laster i akterskipet?

Aktuelle verktøy for å besvare spørsmålene er slamming-beregninger med potensialteori (verktøy implementert i ShipX), enkle motstandsberegninger, CFD-beregninger, samt modellforsøk.

 

Oppgave foreslått av Leif Vartdal, Rolls-Royce Marine AS

Hovedveileder: Prof. Sverre Steen.