Stabilnost mejne plasti na oscilirajoči plošči v smeri toka

Hlebec Štor, Patrik (author), Brojan, Miha (mentor)

Stabilnost mejne plasti je dokaj obravnavan problem. Nas pa je zanimal vpliv premikanja plošče relativno na tok fluida. Sklepali smo, da bi lahko to sprožilo predčasno tvorbo vrtincev in hitrejše širjenje. Problem smo obravnavali z Orr-Sommerfeldovo enačbo stabilnosti in diskretizacijo v $x$-smeri. Z iskanjem lastnih vrednosti sistema smo iskali trenutek prestopa v nestabilno stanje. Z časovno in prostorsko analizo smo lahko opazovali tudi hitrost širjenja potenj po prostoru. Vmesni rezultati so kazali, da oscilacije nimajo vpliva (da je stabilnost odvisna le od $Re_\delta$), vendar se je kasneje, iz nadaljnjih numeričnih simulacij, sklepamo, da imajo oscliacije vpliv na širjenje motenj po prostoru. Vpliv na trenutek prehoda v nestabilnost smo opazovali preko oblike stabilnostnih kontur.

• Language: Slovenian
• Keywords: časovna stabilnost, prostorska stabilnost, mejne plasti, oscilirajoče plošče, Orr-Sommerfeld
• Work type: Final paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FS - Faculty of Mechanical Engineering
• Place of publishing: Ljubljana
• Publisher: [P. Hlebec Štor]
• Year: 2021
• Number of pages: IX, 24 str.
• PID: 20.500.12556/RUL-130458
• UDC: 532.526:531.36:517.9(043.2)
• COBISS.SI-ID: 83875587
• Publication date in RUL: 15.09.2021

HLEBEC ŠTOR, Patrik, 2021, Stabilnost mejne plasti na oscilirajoči plošči v smeri toka [online]. Bachelor’s thesis. Ljubljana : P. Hlebec Štor. [Accessed 23 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=130458

Secondary language

• Language: English
• Title: The Stability of the boundary layer on an oscillating plate in the direction flow

Abstract

The stability of the boundary layer is a fairly addressed problem. We were, however, interested in the influence of plate movement relative to fluid flow. We hypothesized that this could trigger premature vortex formation and faster spread. We addressed the problem with the Orr-Sommerfeld equation of stability and discretization in the $x$-direction. By searching for the eigenvalues of the system, we searched for the moment of transition to an unstable state. With temporal and spatial analysis, we were also able to observe the rate of spread of instability throughout space. Intermediate results showed that the oscillations have no effect (that the stability depends only on $Re_\delta$), but later, from further numerical simulations, we concluded that the oscillations have an effect on the propagation of perturbations throughout space. The influence on the moment of transition to instability was observed through the shape of the stability contours.

• Keywords: temporal stability, spatial stability, boundary layers, oscillating plates, Orr-Sommerfeld