Utjecaj trima na ukupni otpor modela kontejnerskog broda u ograničenoj vodi

undergraduate thesis

• Title (english): Effect of trim on the total resistance of a container ship model in confined water
• Author: Barbara Anušić
• Mentor: Nastia Degiuli (mentor)
• Mentor: Ivana Martić (komentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2024-03-01, 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 KCS modela broda primjenom računalne dinamike fluida pomoću programskog paketa STAR – CCM+. U numeričkim simulacijama korišten je model nestacionarnog trodimenzijskog strujanja viskoznog fluida sa slobodnom površinom temeljen na Reynoldsovim osrednjenim Navier – Stokesovim (RANS) jednadžbama te SST modelu turbulencije. Primijenjena je metoda udjela fluida u volumenu (VOF) s ciljem određivanja položaja slobodne površine. Numeričke simulacije provedene su za ravnu vodnu liniju te četiri kuta trima za jedan Froudeov broj u vodi ograničene širine i dubine. Proveden je postupak verifikacije primjenom mreža različitih gustoća i vremenskih koraka te je izračunata numerička nesigurnost pri određivanju ukupnog otpora, urona i kuta trima. Dobiveni numerički rezultati uspoređeni su s eksperimentalnim rezultatima dostupnim u literaturi. Provedena je detaljna analiza položaja slobodne površine, slike valova, raspodjele hidrodinamičkog tlaka i tangencijalnih naprezanja, strujanja oko modela broda te polja brzine na simetralnoj ravnini. Dana je usporedba dobivenih vrijednosti ukupnog otpora za ravnu vodnu liniju i sve ispitane kutove trima. Zaključeno je da je podešavanjem kuta trima moguće smanjiti ukupni otpor modela broda u ograničenoj i plitkoj vodi s ciljem postizanja veće energetske učinkovitosti broda u ograničenim plovnim putovima.

Abstract (english)

In this study, numerical simulations of resistance tests for the KCS ship model are carried out within a commercial software package STAR – CCM+ for computational fluid dynamics. A mathematical model of unsteady three–dimensional viscous flow with a free surface based on Reynolds Averaged Navier – Stokes (RANS) equations and the k – ω SST turbulence model is applied. The volume of fluid (VOF) method is used to track and locate the free surface. Numerical simulations are performed for an even keel and four trim angles for one Froude number in water of limited width and depth. The verification study is carried out using different grid resolutions and time steps, and the numerical uncertainty for the total resistance, sinkage, and trim angle is calculated. The obtained numerical results are compared with the experimental results available in the literature. A detailed analysis of the free surface elevation, wave patterns, distribution of hydrodynamic pressure and wall shear stress, flow around the ship model, and velocity field on the symmetry plane is carried out. A comparison of the obtained values of total resistance for an even keel and all considered trim angles is given. It has been concluded that it is possible to reduce the total resistance of the ship model in constrained and shallow water by adjusting the trim angle to increase the ship energy efficiency in restricted waterways.

• Keywords: kut trima; pokus otpora; ograničena i plitka voda; računalna dinamika fluida; Reynoldsove osrednjene Navier – Stokesove jednadžbe; metoda udjela fluida u volumenu; model turbulencije
• Keywords (english): trim angle; resistance test; confined and shallow water; computational fluid dynamics; Reynolds Averaged Navier–Stokes equations; Volume of Fluid method; k – ω SST turbulence model
• Language: croatian
• URN:NBN: urn:nbn:hr:235:167068
• Project: Number: IP-2020-02-8568; Title: Održiva plovidba smanjenom brzinom za nisko-ugljično brodarstvo; Title: Sustainable slow steaming for low carbon shipping; Acronym: STARSHIP; Leader: Nastia Degiuli; Jurisdiction: Croatia; Funder: HRZZ; Funding stream: IP
• Study programme: Title: Naval Architecture; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka brodogradnje (sveučilišni prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka brodogradnje)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-02-28 18:37:36