Sökning: "ship wake"

Visar resultat 1 - 5 av 14 avhandlingar innehållade orden ship wake.

  1. 1. Towards Accurate Numerical Methods for Ship Flows on Composite Overlapping Grids

    Författare :Lars Carlsson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary layer; wake; incompressible flow; Navier-Stokes; composite overlapping grids; grid generation; ship flow; parallel computing; alternating-direction implicit; line-implicit;

    Sammanfattning : Numerical methods are presented that are designed to make accurate ship-flow computations more feasible. One method concerns the automatic generation of high-quality computational grids. It treats the grids as competing individuals in a population, where an individual's fitness is based on a measure of grid quality. LÄS MER

  3. 2. Turbulent ship wakes and their spatiotemporal extent

    Författare :Amanda Nylund; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; shipping; ship wake; turbulence; environmental impact;

    Sammanfattning : Shipping activities occur in almost every part of the global oceans and in intensely trafficked shipping lanes there can be up to one ship passage every ten minutes. All these ships impact the marine environment in different ways through pollution or physical disturbance. LÄS MER

  4. 3. Characterising turbulent ship wakes from an environmental impact perspective

    Författare :Amanda Nylund; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; stratification; ship wake; turbulence; methane emission; shipping; energy pollution; environmental impact;

    Sammanfattning : The world’s oceans, especially coastal areas, are intensively trafficked by ships. All these ships exert pressure on the marine environment, through emission to the atmosphere, discharges of pollutants to the water, and physical disturbance through energy input. Of these impacts, energy pollution from shipping has received the least attention. LÄS MER

  5. 4. On Turbulence Modelling for Bilge Vortices: A Test of Eight Models for Three Cases

    Författare :Urban Svennberg; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wake; turbulence modelling; nonlinear eddy-viscosity model; bilge vortices; ship flow; jet; Navier-Stokes equation; two-equation model; Reynolds stress model; vortex;

    Sammanfattning : This work is a test, in three steps, of turbulence models for the calculation of the flow field around ships. Eight models ranging from k-e and k-w models to a Reynolds-stress model (RSM) are tested. LÄS MER

  7. 5. Numerical Investigation of Ship Responses in Calm Water and Regular Head Waves

    Författare :Mohsen Irannezhad; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Nominal wake; Resistance; CFD; RANS; FNPF; Regular head waves; Ship motions;

    Sammanfattning : In order to design fuel efficient ships and install right machinery onboard, ship designers need to know the interaction effects between hull, propeller and appendages in realistic operating conditions. Neglecting the interaction effects may result in under/over-prediction of the required power. LÄS MER