Azenić, Adam (2014) Numerička simulacija povezanog numeričkog modela strujanja i akustičkog modela. = Numerical simulation of acoustic response coupled with flow. Undergraduate thesis , Sveučilište u Zagrebu, Fakultet strojarstva i brodogradnje, UNSPECIFIED. Mentor: Jasak, Hrvoje.
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06_03_2014_Zavrsni_rad.pdf - Published Version Jezik dokumenta:English Download (3MB) | Preview |
Abstract (Croatian)
Ako tok fluida nastrujava na klinasti objekt, fluid se ne odvaja jednakomjerno na obje strane klina, već nakon vrlo kratkog perioda počinju nestacionarnosti te odvajanje vrtloga naizmjenično s jedne strane na drugu, što u određenim situacijama izaziva slabi tlačni poremećaj, odnosno zvuk. Ova pojava, koja se zove *edge tone* nije nimalo jednostavna i predvidljiva, unatoč geometrijskoj jednostavnosti klina koji je uzrokuje. Jedan od primjera pojave *edge tone*-a je generiranje zvuka nastrujavanjem zraka iz ustiju na pisak puhaćeg instrumenta. Osim u glazbenoj industriji, pojava je prisutna i u mnogim drugim situacijama, kao što je generiranje buke na nosaču tereta na krovu automobila ili pojava zvuka prilikom puhanja u zviždaljku. U radu je provedeno šesnaest simulacija na pet različitih mreža prostorne diskretizacije s tri modela strujanja: laminarni model te i modeli turbulencije. U skladu s literaturom, rezultati pokazuju postojanje više dominantnih frekvencija, odnosno stadija. Dane su usporedbe dobivenih dominantnih frekvencija osciliranja za sve slučajeve u više točaka unutar domene proračuna. Proračuni su uspoređeni i s obzirom na mrežu prostorne diskretizacije i model turbulencije koji se koristi u pojedinom proračunu.
Abstract
If a fluid flow is directed at a wedge, the fluid does not divide equally on both sides of the wedge, but after a very short period of time instabilities appear and vortexes start to shed from one side to another, what, in specific circumstances, induces a small pressure disturbance or a sound. This phenomenon, the edge tone, is not simple and predictable, despite geometrical simplicity of the wedge that induces it. One of the examples of edge tone is sound generation by directing an air from mouth on a mouthpiece of a wind instrument. Beside music industry, edge tone is present in many other situations, such as noise generation on a load carrier on a car roof or sound apperance when blowing into a whistle. In this project sixteen simulations have been made on five different meshes with three flow models: laminar model and k and k SST turbulence models. In accordance with the literature, the results have shown the existence of more dominant frequencies or stages. The comparisons of dominant frequencies have been given for all the cases in several monitoring points inside computation domain. Simulations have also been compared considering the mesh and turbulence model that are used in each simulation.
| Item Type: | Thesis (Undergraduate thesis) |
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| Uncontrolled Keywords: | *edge tone*; frekvencija osciliranja; modeli turbulencije; nestacionarnost |
| Keywords (Croatian): | edge tone, frequency of oscilation, turbulence models, instability |
| Divisions: | 500 Department of Energy, Power Engineering and Environment > 530 Chair of Turbomachinery |
| Date Deposited: | 22 Sep 2014 18:00 |
| Last Modified: | 16 Oct 2015 12:45 |
| URI: | http://repozitorij.fsb.hr/id/eprint/2766 |
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