Slobodna površina

U fizici, slobodna površina je površina tijela koja nije predmet ni okomitog normalnog napona, niti paralelnog tangencijalnog napona,^[1] kao što je granica između dva homogena fluida,^[2] na primjer, tečne vode i zraka u Zemljinoj atmosferi. Za razliku od tečnosti, plinovi ne mogu formirati slobodnu površinu sami od sebe.

Tečnost u gravitacionom polju će formirati slobodnu površinu ako spremnik sa tekućinom nije zatvoren odozgo.^[3] Po mehaničkoj ravnoteži ova slobodna površina mora biti okomita na sile koje djeluju na fluid; ako to nije slučaj, onda postoji slika koja djeluje duž površine, uslijed koje bi fluid strujao u smijeru te iste sile. Zbog toga, na površini Zemlje, sve slobodne površine tečnosti su horizontalne ukoliko nema poremećaja.

Slični termini

U dinamici fluida, vrtlog slobodne površine, poznat i kao potencijalni vrtlog ili vir, formira se u nerotacionom strujanju,^[4] na primjer, kada izvadimo čep iz kade napunjene vodom.^[5]
U mehanici fluida, strujanje ispod slobodne površine, poznato i kao strujanje u otvorenom kanalu, je strujanje fluida potpomognuto silom gravitacije ispod slobodne površin, najčešće strujanje vode ispod zraka u atmosferi.^[6]

Također pogledajte

Reference

^ "Glossary: Free Surface". Interactive Guide. Vishay Measurements Group. Pristupljeno 2. 12. 2007. Surface of a body with no normal stress perpendicular or shear stresses parallel to it…
^ Free surface. McGraw-Hill Dictionary of Scientific and Technical Terms. McGraw-Hill Companies, Inc., 2003. Answers.com. Retrieved on 2007-12-02.
^ name=White>White, Frank (2003). Fluid mechanics. New York: McGraw-Hill. str. 4. ISBN 0-07-240217-2.
^ Brighton, John A.; Hughes, William T. (1999). Schaum's outline of theory and problems of fluid dynamics. Boston, Mass: McGraw Hill. str. 51. ISBN 0-07-031118-8. A simple example of irrotational flow is a whirlpool, which is known as a potential vortex in fluid mechanics.CS1 održavanje: više imena: authors list (link)
^ "Ricerca Italiana - PRIN - Global stability of three-dimensional flows". Arhivirano s originala, 9. 2. 2012. Pristupljeno 2. 12. 2007. The free-surface vortex (whirlpool) that occurs during the draining of a basin has received different interpretations along its history;
^ White, Frank M. (2000). "2.5 Open Channel Flow". u Kreith, Frank (ured.). The CRC Handbook of Thermal Engineering (Mechanical Engineering). Berlin: Springer-Verlag and Heidelberg. str. p. 2-61. ISBN 3-540-66349-5. The term open channel flow denotes the gravity-driven flow of a liquid with a free surface.

[titleGlossary:_Free_Surface-1] "Glossary: Free Surface". Interactive Guide. Vishay Measurements Group. Pristupljeno 2. 12. 2007. Surface of a body with no normal stress perpendicular or shear stresses parallel to it…

[2] Free surface. McGraw-Hill Dictionary of Scientific and Technical Terms. McGraw-Hill Companies, Inc., 2003. Answers.com. Retrieved on 2007-12-02.

[3] =White>White, Frank (2003). Fluid mechanics. New York: McGraw-Hill. str. 4. ISBN 0-07-240217-2.

[isbn0-07-031118-8-4] Brighton, John A.; Hughes, William T. (1999). Schaum's outline of theory and problems of fluid dynamics. Boston, Mass: McGraw Hill. str. 51. ISBN 0-07-031118-8. A simple example of irrotational flow is a whirlpool, which is known as a potential vortex in fluid mechanics.CS1 održavanje: više imena: authors list (link)

[titleRicerca_Italiana_-_PRIN_-_Global_stability_of_three-dimensional_flows-5] "Ricerca Italiana - PRIN - Global stability of three-dimensional flows". Arhivirano s originala, 9. 2. 2012. Pristupljeno 2. 12. 2007. The free-surface vortex (whirlpool) that occurs during the draining of a basin has received different interpretations along its history;

[White-6] White, Frank M. (2000). "2.5 Open Channel Flow". u Kreith, Frank (ured.). The CRC Handbook of Thermal Engineering (Mechanical Engineering). Berlin: Springer-Verlag and Heidelberg. str. p. 2-61. ISBN 3-540-66349-5. The term open channel flow denotes the gravity-driven flow of a liquid with a free surface.

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