Nova metoda za računalno modeliranje atmosferskog graničnog sloja

master's thesis

• Title (english): A novel method for computational modelling of the atmospheric boundary layer
• Author: Mihael Cindori
• Mentor: Franjo Juretić (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2016-01-22, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

U ovom radu predložena je nova metoda za računalno modeliranje stacionarnog homogenog atmosferskog graničnog sloja koristeći računalnu dinamiku fluida. Metoda se temelji na uvođenju

novog izvorskog člana u jednadžbu količine gibanja čija je glavna svrha postizanje homogenog strujanja u graničnom sloju. Početna vrijednost izvorskog člana se računa korištenjem eksperimentalnih vrijednosti naprezanja dobivenih simulacijom atmosferskog graničnog sloja u

zračnom tunelu. S ciljem postizanja strujanja što sličnijeg eksperimentu, tijekom proračuna je vršena korekcija vrijednosti izvorskog člana. U radu je modeliran atmosferski granični sloj mjeren u zračnom tunelu.

Za modeliranje turbulencije je korišten standardni k − ε model turbulencije uz izmjenjene vrijednosti koeficijenata modela.

Točnost računalnog modela je provjerena na ruralnom, suburbanom i urbanom tipu terena, te su u radu dani rezultati za brzinu, naprezanje i turbulentnu kinetičku energiju dobiveni na tri različita mjesta u računalnoj domeni (na ulazu i izlazu, te u sredini domene). Na taj način je pokazano da novi model omogućuje modeliranje homogenog atmosferskog graničnog sloja, te su greške simulacije u većini domene manje od ±10%.

Abstract (english)

A novel approach for computational modelling of the steady-state neutrally-stratified atmospheric boundary layer was introduced in this work. The approach is based on the introducing of a new source term in the momentum equation, implemented to establish the homogeneous characteristics of the flow. The initial value of the term is calculated from experimental stress values and the corrections were applied during the calculation in order to obtain exact results.

The atmospheric boundary layer, modelled in this work, was previously established and measured in a wind tunnel.

Turbulence is modelled by using the standard k − ε turbulence model with modified coefficients.

A new model was validated on the rural, suburban and urban terrain and computational results for velocity, stress and turbulent kinetic energy were sampled at inlet, outlet and middle part of the computational domain. Thus, it is shown that new approach can be used for simulations of the steady-state neutrally-stratified atmospheric boundary layer with errors not larger than ±10% in most parts of the computational domain.

• Keywords: Stacionarni homogeni atmosferski granični sloj; računalna dinamika fluida; stacionarni k − ε model turbulencije
• Keywords (english): Steady-state neutrally-stratified atmospheric boundary layer; computational modelling; steady RANS; k − ε turbulence model
• Language: croatian
• URN:NBN: urn:nbn:hr:235:010754
• 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 15:26:29