Utjecaj položaj ruku na aerodinamičke karakteristike skijaša letača

undergraduate thesis

• Title (english): Aerodynamic characteristics of ski jumper influenced by position of his arms
• Author: Dino Golubić
• Mentor: Hrvoje Kozmar (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2016-03-02, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

U ovom završnom radu istražen je utjecaj položaja ruku skijaša letača na duljinu njegova skoka. Duljina skoka velikim je dijelom uvjetovana odnosom sile uzgona i otpora skijaša pa su te dvije aerodinamičke sile te njihov omjer promatrani tijekom numeričke analize. Tijelo skijaša letača modelirano je u CAD programskom paketu SolidWorks na pojednostavljeni način kako je i prethodno bilo modelirano u sličnim radovima. Modelirana su tri modela skijaša letača s različitim položajem ruku u odnosu na tijelo: a) ruke pod 0° (uz tijelo), b) ruke pod 45°, c) ruke pod 90°. Proračunska domena s jednom ravninom simetrije napravljena je u programskom paketu Salome. Domena je strukturirano ispunjena mrežom heksaedarskih konačnih volumena uz veća profinjenja u blizini tijela skijaša uz korištenje programskog paketa cfMesh. Numerički proračun proveden je u računalnom programu OpenFOAM uz stacionarne uvjete strujanja. Uz aerodinamičke sile otpora i uzgona u radu su prikazana i polja tlaka i brzine oko tijela skijaša te je provedena diskusija rezultata.

Abstract (english)

In this bachelor thesis, the aerodynamic forces experienced by a generic ski jumper are studied. The focus is on the position of ski jumper’s arms with respect to his body. As the length of the jump is largely determined by the lift to drag force ratio of the ski jumper, these two aerodynamic forces are analyzed using Computational Fluid Dynamics (CFD) simulations. Ski jumper’s body is modeled in the SolidWorks CAD software package in a simplified way similar to previous studies. Three models of the ski jumper with different placement of arms with respect to his body are modeled, i.e. a) arms at 0° (close to body), b) arms at 45° , c) arms at 90° . Computational domain with one symmetry plane is created in the Salome software package. The domain is structurally filled with the grid of hexahedron cells along with refinements close to the ski jumper‘s body using the cfMesh software package. The CFD simulations are carried out using the OpenFOAM software package, SST k− ω turbulence model and stationary flow conditions. The aerodynamic drag and lift forces, as well as pressure and velocity fields around the ski jumper are reported and discussed.

• Keywords: Računalna dinamika fluida; metoda konačnih volumena; omjer sile uzgona i otpora; skijaš letač
• Keywords (english): Computational fluid dynamics; finite volume method; lift-to-drag ratio; ski jumper
• Language: croatian
• URN:NBN: urn:nbn:hr:235:883893
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-05-27 10:09:17