Utjecaj trima na ukupni otpor kontejnerskog broda

master's thesis

• Title (english): Effect of trim on the total resistance of a container ship
• Author: Katarina Martić
• Mentor: Nastia Degiuli (mentor)
• Mentor: Ivana Martić (komentor)
• Committee member: Ivan Ćatipović (predsjednik povjerenstva)
• Committee member: Nastia Degiuli (član povjerenstva)
• Committee member: Neven Hadžić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2022-07-21, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Shipbuilding; Hydromechanics of Floating and Maritime Structures

Abstract

U ovom radu provedene su numeričke simulacije pokusa otpora za 6750-TEU kontejnerski brod u naravi za pet različitih kutova trima primjenom računalne dinamike fluida (RDF). Numeričke simulacije provedene su primjenom komercijalnog programskog paketa
STAR–CCM+ s ciljem određivanja optimalnog trima pri kojem je ukupni otpor broda najmanji. Dan je matematički model nestacionarnog trodimenzijskog viskoznog strujanja fluida sa slobodnom površinom, koji se temelji na Reynoldsovim osrednjenim
Navier–Stokesovim jednadžbama (eng. Reynolds Averaged Navier–Stokes, RANS) i
k–ω SST modelu turbulencije. Za opis slobodne površine primijenjena je metoda udjela fluida u volumenu (eng. Volume of Fluid, VOF). Proveden je postupak verifikacije za gustoću mreže i vremenski korak u svrhu određivanja ukupne nesigurnosti numeričke simulacije. Nadalje, rezultati numeričkih simulacija validirani su s ekstrapoliranim rezultatima modelskih ispitivanja provedenih u Brodarskom institutu. Analizirano je strujanje duž trupa broda, raspodjela tangencijalnih naprezanja po oplakanoj površini, slike valova oko trupa broda te raspodjela hidrodinamičkog tlaka za različite kutove trima. Konačno, dana je preporuka optimalnog trima za projektnu brzinu broda.

Abstract (english)

In this paper, numerical simulations of resistance test for a 6750–TEU container ship in full scale are carried out at five different trim angles using Computational Fluid Dynamics (CFD). Numerical simulations are performed using a commercial software package STAR-CCM+ in order to determine the optimal trim with the lowest value of the total resistance. A mathematical model of unsteady three-dimensional viscous flow with a free surface based on Reynolds Averaged Navier–Stokes (RANS) equations and k–ω SST turbulence model is given. The Volume of Fluid (VOF) method is used to describe the free surface. A verification study is performed for grid density and time step to determine the total numerical uncertainty. Furthermore, the obtained results of the numerical simulations are validated against the extrapolated results of the model tests performed in the Brodarski institute. The flow along the ship hull, shear stress distribution on the wetted surface, wave patterns, and hydrodynamic pressure distribution are analysed for different trim angles. Finally, the recommendation for the optimal trim at the design speed is given.

• Keywords: kontejnerski brod; pokus otpora; trim; računalna dinamika fluida; Reynoldsove osrednjene Navier-Stokesove (RANS) jednadžbe; k–ω SST model turbulencije
• Keywords (english): container ship; resistance test; trim; Computational Fluid Dynamics; Reynolds Averaged Navier-Stokes equations; k–ω SST turbulence model
• Language: croatian
• URN:NBN: urn:nbn:hr:235:977249
• Study programme: Title: Naval Architecture; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka brodogradnje (magistar/magistra inženjer/inženjerka brodogradnje)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Embargoed access; Embargo expiration date: 2024-07-21
• Created on: 2022-07-20 06:40:00