Numeričke simulacije stlačivog strujanja fluida korištenjem spregnutog algoritma

master's thesis

• Title (english): Numerical simulation of compressible flows using a coupled density-based solution algorithm
• Author: Karlo Šunjo
• Mentor: Hrvoje Jasak (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2014-07-18, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

U ovom radu izvršit će se validacija numeričkog algoritma za rješavanje strujanja visokog Machovog broja. Algoritam je pisan u okruženju OpenFOAM te je nov u tom kontekstu. Prvo će se opisati glavne matematičke i numerike probleme koje se susreće u teoriji poput Riemannovog problema te načina rješavanja tog problema. Opisani su ponuđeni rješavači Riemannovog problema uz ostale diskretizacijske sheme koje su standardne u računalnoj dinamici fluida. Algoritam koji koristi gustoću kao glavnu proračunsku varijablu će se validirati na temelju slučajeva za koje se moglo naći eksperimentalne i numeričke rezultate. Pokazalo se kako djeluje profinjenje proračunske mreže na rezultate te kakve rezultate daje u odnosu na algoritme koji koriste tlak kao glavnu proračunsku varijablu. U proračunima je korišten isključivo k - omega SST model turbulencije zbog visokih iznosa Reynoldsovog broja, osim u jednom slučaju za kojeg se pretpostavilo kvazilaminarno strujanje. Slučajevi koji su uzeti su geometrije krila, jednostavni "shock tube" i kovergentno-divergentne mlaznice. Rezultati proračuna će se prikazati grafički u vidu polja primitivnih varijabli i bezdimenzijskih značajki te će ih se usporediti s postojećim eksperimentalnim i referentnim numeričkim rješenjima.

Abstract (english)

In this work the validation of new algorithm was done. Algorithm is written in OpenFOAM environment and it is new in that context. Firstly, main mathematical and numerical problems were introduced as well as ways to solve those problems such as Riemann problem. Approximate Riemann solvers which are available in new code were theoretically described. This algorithm which uses density as main calculation variable was validated against cases for wich results were available in literature or internet. The impact of mesh re nement was shown and also the comparison against pressure-based algorithm. In all cases except one k - omega SST turbulence model was used because of very high Reynolds numbers. In one of cases quasi-laminar ow was assumed. Geometries in simulated cases are a transonic wing, shock-tube and convergent-deivergent nozzles, namely, cases that are of interes of industry. Results of simulations were graphically shown as elds of primitive variables and dimensionless numbers.

• Keywords: stlačiva strujanja; računalna dinamika fluida; density-based; coupled solver; OpenFOAM
• Keywords (english): compressible flow; computational fluid dynamics; density-based; coupled solver; OpenFOAM
• Language: english
• URN:NBN: urn:nbn:hr:235:924169
• 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: 2019-05-22 11:15:59