Sökning: "non-linear free-surface"

Visar resultat 1 - 5 av 12 avhandlingar innehållade orden non-linear free-surface.

1. 1. Conduction laser welding : modelling of melt pool with free surface deformation

   Författare :Josefine Svenungsson; Högskolan Väst; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Conduction laser welding; numerical modelling; Computational Fluid Dynamics; OpenFOAM; free surface deformation; melt pool; Production Technology; Produktionsteknik; Manufacturing and materials engineering; Produktions- och materialteknik;

   Sammanfattning : Laser welding is commonly used in the automotive-, steel- and aerospace industry. It is a highly non-linear and coupled process where the weld geometry is strongly affected by the flow pattern in the melt pool. Experimental observations are challenging since the melt pool and melt flow below the surface are not yet accessible during welding. LÄS MER

3. 2. Potential Flow Panel Methods for the Calculation of Free-surface Flows with Lift

   Författare :Carl-Erik Janson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; desingularized; shape optimization; Rankine source; waves; OCTOPUS; dipole; MMA; Dawson operator; boundary layer; vortex; Method of Moving Asymptotes; nonlinear; sailing yacht; four point operator; surface piercing wing; Navier-Stokes; numerical method; lift force; raised panel method; discrete Fourier transform; collocation point shift; potential flow; CFD; free surface; induced drag; SHIPFLOW; dispersion; damping; analytical method; hydrofoil;

   Sammanfattning : Two non-linear Rankine-source panel methods are developed and implemented in the same computer code. The first method uses a four-point upwind operator on the free-surface to compute the velocity derivatives and to enforce the radiation condition while the second method uses an analytical expression for the velocity derivatives and a collocation point shift one panel upstream to prevent upstream waves. LÄS MER

4. 3. Investigations of Waterjet/Hull Interaction Effects

   Författare :Arash Eslamdoost; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; pressure jump method; thrust deduction; numerical simulation; waterjet propulsion; gross thrust; trim angle; waterjet hull interaction; net thrust; potential flow; sinkage; non-linear free-surface;

   Sammanfattning : A waterjet propulsor operates in a different way than a conventional propeller. This makes it hard to use the same concepts for studying the thrust and powering of these systems. LÄS MER

5. 4. The Hydrodynamics of Waterjet/Hull Interaction

   Författare :Arash Eslamdoost; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; trim angle; vena-contracta; transom clearance; net thrust; waterjet hull interaction; waterjet propulsion; capture area; exit drag; non-linear free-surface; intake drag; gross thrust; sinkage; streamtube; RANS; thrust deduction; potential flow; VOF;

   Sammanfattning : The objective of the present investigation is to explore the physics behind the waterjet/hull interaction, and in particular the negative thrust deduction often reported in the semi-planing speed range. Another objective is to propose a validated numerical technique for computing the hydrodynamics of waterjet-driven hulls. LÄS MER

7. 5. Wave Loads on Offshore Wind Power Plants

   Författare :Jenny Trumars; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ocean engineering; shallow water; fatigue; Non-linear waves; wave load; wind energy converter; perturbation theory;

   Sammanfattning : The thesis gives a short introduction to waves and discusses the problem with non-linear waves in shallow water and how they effect an offshore wind energy converter. The focus is on the realisation of non-linear waves in the time domain from short-term statistics in the form of a variance density spectrum of the wave elevation. LÄS MER