| | SLO | ENG | Cookies and privacy

Bigger font | Smaller font

Search the digital library catalog Help

Query: search in
search in
search in
search in
* old and bologna study programme

Options:
  Reset


1 - 5 / 5
First pagePrevious page1Next pageLast page
1.
Numerical simulations of the flow and aerosol dispersion in a violent expiratory event : Outcomes of the “2022 International Computational Fluid Dynamics Challenge on violent expiratory events
Jordi Pallares, Alexandre Fabregat Tomas, Akim Lavrinenko, Hadifathul Akmal bin Norshamsudin, Gabor Janiga, David Frederick Fletcher, Kiao Inthavong, Marina Zasimova, Vladimir Ris, Nikolay Ivanov, Robert Castilla, Pedro Javier Gamez-Montero, Gustavo Raush, Hadrien Calmet, Daniel Mira, Jana Wedel, Mitja Štrakl, Jure Ravnik, Douglas Hector Fontes, Francisco José De Souza, Cristian Marchioli, Salvatore Cito, 2023, original scientific article

Abstract: This paper presents and discusses the results of the “2022 International Computational Fluid Dynamics Challenge on violent expiratory events” aimed at assessing the ability of different computational codes and turbulence models to reproduce the flow generated by a rapid prototypical exhalation and the dispersion of the aerosol cloud it produces. Given a common flow configuration, a total of 7 research teams from different countries have performed a total of 11 numerical simulations of the flow dispersion by solving the Unsteady Reynolds Averaged Navier–Stokes (URANS) or using the Large-Eddy Simulations (LES) or hybrid (URANS-LES) techniques. The results of each team have been compared with each other and assessed against a Direct Numerical Simulation (DNS) of the exact same flow. The DNS results are used as reference solution to determine the deviation of each modeling approach. The dispersion of both evaporative and non-evaporative particle clouds has been considered in 12 simulations using URANS and LES. Most of the models predict reasonably well the shape and the horizontal and vertical ranges of the buoyant thermal cloud generated by the warm exhalation into an initially quiescent colder ambient. However, the vertical turbulent mixing is generally underpredicted, especially by the URANS-based simulations, independently of the specific turbulence model used (and only to a lesser extent by LES). In comparison to DNS, both approaches are found to overpredict the horizontal range covered by the small particle cloud that tends to remain afloat within the thermal cloud well after the flow injection has ceased.
Keywords: numerical simulations, computational fluid dynamics
Published in DKUM: 28.03.2024; Views: 368; Downloads: 449
.pdf Full text (8,63 MB)
This document has many files! More...

2.
3.
Modeliranje ekscentričnih trkov v večfaznem toku
Mitja Štrakl, 2018, master's thesis

Abstract: V magistrskem delu je opisan proces izdelave numeričnega modela detekcije in obravnave ekscentričnega trka za namen raziskovanja problematike iz področja interakcij delcev v večfaznih tokovih. Matematični model temelji na predpostavki o idealno togem trku, z zanemarljivim prispevkom trenja. Numerična formulacija je sestavljena iz diskretizacije geometrije trodimenzionalnih delcev, detekcije trka med delci z določanjem stopnje prekrivanja, transformacije vektorskih veličin v koordinatni sistem obravnave, numeričnega reševanja sistema enačb in aplikacije rezultatov na gibalno stanje. Zgrajeni model je bil preverjen skozi proces verifikacije z poznanimi analitičnimi primeri trkov delcev, ter skozi proces validacije s spremljanjem ohranitve energije skozi obravnavo gruče naključnih trkov. Glede na rezultate je v zaključnem sklepu model bil prepoznan kot primeren za obravnavo namenske problematike, z upoštevanjem omejitev, predstavljenih skozi vsebino te naloge.
Keywords: večfazni tok, ekscentrični trk, detekcija trka, numerični model
Published in DKUM: 11.09.2018; Views: 1318; Downloads: 205
.pdf Full text (2,68 MB)

4.
Optimizacija hlajenja zavornega diska pri osebnem avtomobilu
Mitja Štrakl, 2015, undergraduate thesis

Abstract: V diplomskem delu je obravnavano hlajenje zavornega diska, s pomočjo metod računalniške dinamike tekočin. Tokovno polje je simulirano stacionarno pri konstantni hitrosti vožnje, prenos toplote pa je simuliran časovno odvisno. Zrak je modeliran kot idealen plin s konstantnimi lastnostmi, za material zavornega diska pa so izbrane lastnosti jekla. Po izvedeni analizi serijskega zavornega sistema vozila BMW serije 5, je v nadaljevanju obravnavana študija razmer pri vpihovanju hladilnega zraka in optimizacija takšnega sistema v smeri izboljšanja odvoda toplote. Rezultati opravljene analize prikazujejo pomembno povečanje hladilne moči pri implementaciji sistema za vpihovanje hladilnega zraka.
Keywords: zavorni disk, numerična analiza, računalniška dinamika tekočin
Published in DKUM: 27.10.2015; Views: 1493; Downloads: 186
.pdf Full text (6,51 MB)

5.
Search done in 0.15 sec.
Back to top
Logos of partners University of Maribor University of Ljubljana University of Primorska University of Nova Gorica