Validacija metode uronjene granične površine u numeričkoj mehanici fluida

master's thesis

• Title (english): Validation of the immersed boundary surface method in computational fluid dynamics
• Author: Robert Anderluh
• Mentor: Hrvoje Jasak (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2019-03-29, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

Cilj ovog rada je predstaviti teorijsku i praktičnu pozadinu metode uronjene granice implementirane u foam-extend 4.1, odnosno njene prednosti i nedostatke.
Glavni cilj metode uronjene granice je pojednostavljenje izrade mreža u računalnoj dinamici fluida, što može dovesti do značajnog smanjenja količine ljudskog rada koji se mora uložiti pri pripremanju simulacija u računalnoj dinamici fluida, pogotovo kod simulacija sa složenim geometrijama. Također, metoda uronjene granice može donijeti određene prednosti kod simulacija s pomičnim mrežama, u vidu smanjenja računalne zahtjevnosti takvih simulacija.
Glavni nedostatak metode uronjene granice je smanjenje točnosti rješenja na uronjenim granicama (površinama simuliranih objekata).
Metoda uronjene granice implementirana u foam-extend 4.1 je ovdje validirana na trima slučajevima: unutarnje strujanje u 2-D slučaju u cijevi sa naglim proširenjem, vanjsko strujanje oko Onera M6 krila i strujanje u Francisovoj turbini, što je pogotovo zanimljiv slučaj za metodu uronjene granice. Rezultati simulacija izvedenih uporabom metodom uronjene granice su uspoređeni sa rezultatima simulacija izvedenim konvencionalnim načinom izrade mreže.
Rezultati simulacija su zadovoljavajući, odnosno, smanjenje točnosti rješenja na uronjenim granicama je dovoljno maleno da implementaciju metode uronjene granice u foam-extend 4.1 možemo ocjeniti kao dobru.

Abstract (english)

The aim of this thesis is to describe the Immersed Boundary Method version implemented in foam-extend 4.1, both its advantages and shortcomings.
The main goal of the Immersed Boundary Method is to simplify the mesh generation process in Computational Fluid Dynamics, which can lead to drastic reductions of human time needed for setting up simulations, especially for simulations with complex geometries. Additionally, it can offer certain advantages in simulations with moving meshes, as it can decrease the computational requirements of such cases.
The main shortcoming of the Immersed Boundary Method is loss of solution accuracy on immersed boundaries (surfaces of simulated objects).
The foam-extend 4.1 Immersed Boundary Method is here validated on three cases: internal 2-D flow over a backward facing step, external flow around the Onera M6 wing, and the flow in a model Francis turbine, which is an especially interesting case, concerning the Immersed Boundary Method. The results of the Immersed Boundary Method simulations are compared to the results of equivalent body-fitted (conventional) simulations.
The simulation results are generally satisfactory, as the loss of accuracy was modest enough to assess the foam-extend 4.1 implementation of the Immersed Boundary Method as successful.

• Keywords: računalna dinamika fluida; OpenFOAM; foam-extend; metoda uronjene granice
• Keywords (english): Computational Fluid Dynamics; CFD; OpenFOAM; foam-extend; Immersed Boundary Method; IBM
• Language: english
• URN:NBN: urn:nbn:hr:235:245172
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-05-23 00:37:23