Modelling of Flow in Vertical Porous Structures Solving the Reynolds-Averaged Navier-Stokes Equations (RANS) using the Volume of Fluid Method (VOF)

Stefan Leschka

ISBN 10: 3838654692 / ISBN 13: 9783838654690

Published by Diplom.De Mai 2002, 2002

About this Item

This item is printed on demand - it takes 3-4 days longer - Neuware -Diploma Thesis from the year 2001 in the subject Engineering - Civil Engineering, grade: 2,0, Technical University of Braunschweig (Bauingenieurwesen), language: English, abstract: Inhaltsangabe:Abstract:In this thesis the simulation of the flow in alpha vertical permeable structure with alpha free surface is described. The underlying physical data had been achieved from experiments in a wave flume at the University of Cantabria. For the calibration of the numerical model COBRAS, a VOF type programme developed at Cornell University, the numerical results are compared with the laboratory data. The data analysed comes from 8 free surface sensors, placed inside and outside of the porous structure, and 4 pressure sensors, placed on the impermeable back wall inside the porous structure. An error analysis, using the least square technique, lead to a stepwise improvement of the numerical and the porous media parameters. In this process various grids had been tested, concerning sponge layer length, source function position and cell size. Later the porous media parameter for laminar and turbulent flow had been adjusted. For various wave conditions and porous structure characteristics, the optimal values for these parameters turned out to lay between 0 and 200 for alpha and between 0.45 and 0.8 for beta. The following error analysis yielded to alpha=100 and beta=0.5 usable for all tested wave and porous media characteristics.Inhaltsverzeichnis:Table of Contents:1.Introduction11.1General Introduction11.2Aims of study31.3Contents32.Numerical Modelling52.1Introduction52.2Overview of Numerical Models for Wave prediction62.3Numerical Models for Simulation of Flow in porous media72.3.1Overview of mathematical solutions72.3.2Available numerical models for porous media flow82.4The COBRAS Model92.4.1Overview92.4.2Governing Equations for the Mean Flow92.4.2.1Flow Motion Formulation92.4.2.1.1Navier-Stokes Equations and Boundary Conditions92.4.2.1.2Reynolds Equations and Boundary Conditions122.4.2.2Turbulence Transport Model142.4.2.2.1Transport Equation for Turbulent Kinetic Energy, k142.4.2.2.2The Transport Equation for Turbulent Dissipation Rate, F152.4.2.2.3Assumptions and Determinations of Coefficients in the k-s Model 162.4.2.2.4Boundary Conditions for k and s192.4.2.3Summary of Governing Equations192.4.3Modelling of Flow in Porous Media202.4.4The Volume of Fluid Method252.4.5The Source Function272.4.6The Sponge Layer282.4.7Numerical Algorithm302.5Closing comment313.Vertical Permeable Structures323.1Introduction323.2Motivation of the Experiments343.3Overview of the experiments343.4Closing comment374.Simulation of Flow in Vertical Permeable Structures384.1Introduction384.2Determination of the Mesh Parameters394.2.1Overview394.2.2Source Function Position and Length of Wave Stabilization Zone414.2.3Length of Sponge Layer504.2.4Size of computational Cells564.2.5Overview of chosen Grid Parameters594.3Determination of Porous Media Parameters 604.3.1Overview604.3.2Sensitivity of a and604.3.3Variation of the wave height644.3.4Variation of the wave period674.3.5Variation of the gabion width704.3.6Variation of the stone diameter734.4Closing comment755.Conclusions and Recommendations785.1Conclusions785.1.1Discussion of the influences to the porous media parameters and785.1.2General conclusions805.2Recommendations81 104 pp. Englisch.

Seller Inventory # 9783838654690

Bibliographic Details

• Title: Modelling of Flow in Vertical Porous Structures Solving the Reynolds-Averaged Navier-Stokes Equations (RANS) using the Volume of Fluid Method (VOF)
• Publisher: Diplom.De Mai 2002
• Publication Date: 2002
• Language: English
• ISBN 10: 3838654692
• ISBN 13: 9783838654690
• Binding: Taschenbuch
• Condition: Neu
• Dimensions: 210W x 148H x 8D millimeters 210 millimeters width by 148 millimeters height by 8 millimeters depth
• Weight: 163 grams

About this title

Synopsis

Diplomarbeit, die am 30.11.2001 erfolgreich an einer Technische Universität in Deutschland im Fachbereich Bauingenieurwesen eingereicht wurde. Abstract: In this thesis the simulation of the flow in alpha vertical permeable structure with alpha free surface is described. The underlying physical data had been achieved from experiments in a wave flume at the University of Cantabria. For the calibration of the numerical model COBRAS, a VOF type programme developed at Cornell University, the numerical results are compared with the laboratory data. The data analysed comes from 8 free surface sensors, placed inside and outside of the porous structure, and 4 pressure sensors, placed on the impermeable back wall inside the porous structure. An error analysis, using the least square technique, lead to a stepwise improvement of the numerical and the porous media parameters. In this process various grids had been tested, concerning sponge layer length, source function position and cell size. Later the porous media parameter for laminar and turbulent flow had been adjusted. For various wave conditions and porous structure characteristics, the optimal values for these parameters turned out to lay between 0 and 200 for alpha and between 0.45 and 0.8 for beta. The following error analysis yielded to alpha=100 and beta=0.5 usable for all tested wave and porous media characteristics. Table of Contents: 1.|Introduction|1 1.1|General Introduction|1 1.2|Aims of study|3 1.3|Contents|3 2.|Numerical Modelling|5 2.1|Introduction|5 2.2|Overview of Numerical Models for Wave prediction|6 2.3|Numerical Models for Simulation of Flow in porous media|7 2.3.1|Overview of mathematical solutions|7 2.3.2|Available numerical models for porous media flow|8 2.4|The COBRAS Model|9 2.4.1|Overview|9 2.4.2|Governing Equations for the Mean Flow|9 2.4.2.1|Flow Motion Formulation|9 2.4.2.1.1|Navier-Stokes Equations and Boundary Conditions|9 2.4.2.1.2|Reynolds Equations and Boundary...