QUASI THREE-DIMENSIONAL NEARSHORE CURRENT MODEL USING ONE-EQUATION TURBULENCE MODEL AROUND SUBMERGED BREAKWATERS

2021 ◽  
Vol 77 (2) ◽  
pp. I_775-I_780
Author(s):  
Shuhei MIKI ◽  
Koichi MURAKAMI ◽  
Masamitsu KUROIWA ◽  
Yuki KAJIKAWA
Keyword(s):  
Turbulence Model ◽  
Current Model ◽  
Three Dimensional

MESSINE, a Parametric Three-Dimensional Eddy Current Model

2000 ◽  
Vol 12 (1) ◽  
pp. 65-86 ◽  
Author(s):  
R. La ◽  
B. Benoist ◽  
B. de Barmon ◽  
M. Talvard ◽  
R. Lengelle ◽  
...  
Keyword(s):  
Eddy Current ◽  
Current Model ◽  
Three Dimensional

An eddy-current model for three-dimensional inversion

1986 ◽  
Vol 22 (4) ◽  
pp. 282-291 ◽  
Author(s):  
H. Sabbagh ◽  
L. Sabbagh
Keyword(s):  
Eddy Current ◽  
Current Model ◽  
Three Dimensional

Improvement and validation of a physically based model for the shear and transverse crushing of orthotropic composites

2018 ◽  
Vol 53 (12) ◽  
pp. 1681-1696 ◽  
Author(s):  
Sérgio Costa ◽  
Thomas Bru ◽  
Robin Olsson ◽  
André Portugal
Keyword(s):  
Current Model ◽  
Three Dimensional ◽  
Fracture Plane ◽  
Damage Growth ◽  
Pressure Dependency ◽  
Orthotropic Composites ◽  
Fabric Composites ◽  
Final Failure ◽  
Physically Based ◽  
Nonlinear Shear

This paper details a complete crush model for composite materials with focus on shear dominated crushing under a three-dimensional stress state. The damage evolution laws and final failure strain conditions are based on data extracted from shear experiments. The main advantages of the current model include the following: no need to measure the fracture toughness in shear and transverse compression, mesh objectivity without the need for a regular mesh and finite element characteristic length, a pressure dependency of the nonlinear shear response, accounting for load reversal and some orthotropic effects (making the model suitable for noncrimp fabric composites). The model is validated against a range of relevant experiments, namely a through-the-thickness compression specimen and a flat crush coupon with the fibres oriented at 45° and 90° to the load. Damage growth mechanisms, orientation of the fracture plane, nonlinear evolution of Poisson's ratio and energy absorption are accurately predicted.

scholarly journals Three-Dimensional Turbulent Vortex Shedding From a Surface-Mounted Square Cylinder: Predictions With Large-Eddy Simulations and URANS

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
B. A. Younis ◽  
A. Abrishamchi
Keyword(s):  
Experimental Data ◽  
Turbulence Model ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Large Eddy Simulations ◽  
Navier Stokes ◽  
Reynolds Stresses ◽  
Mean Flow ◽  
Navier Stokes Equations ◽  
Large Eddy

The paper reports on the prediction of the turbulent flow field around a three-dimensional, surface mounted, square-sectioned cylinder at Reynolds numbers in the range 104–105. The effects of turbulence are accounted for in two different ways: by performing large-eddy simulations (LES) with a Smagorinsky model for the subgrid-scale motions and by solving the unsteady form of the Reynolds-averaged Navier–Stokes equations (URANS) together with a turbulence model to determine the resulting Reynolds stresses. The turbulence model used is a two-equation, eddy-viscosity closure that incorporates a term designed to account for the interactions between the organized mean-flow periodicity and the random turbulent motions. Comparisons with experimental data show that the two approaches yield results that are generally comparable and in good accord with the experimental data. The main conclusion of this work is that the URANS approach, which is considerably less demanding in terms of computer resources than LES, can reliably be used for the prediction of unsteady separated flows provided that the effects of organized mean-flow unsteadiness on the turbulence are properly accounted for in the turbulence model.

A Reynolds-Averaged Navier-Stokes Solver in a Turbomachinery Design System

2007 ◽  
Author(s):  
Fahua Gu ◽  
Mark R. Anderson
Keyword(s):  
Turbulence Model ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Integrated Design ◽  
Navier Stokes ◽  
Design System ◽  
Navier Stokes Equations ◽  
Wall Functions ◽  
Machine Performance ◽  
Reynolds Averaged Navier Stokes

The design of turbomachinery has been focusing on the improvement of the machine efficiency and the reduction of the design cost. This paper presents an integrated design system to create the machine geometry and to predict the machine performance at different levels of approximation, including one-dimensional design and analysis, quasi-three-dimensional-(blade-to-blade, throughflow) and full-three-dimensional-steady-state CFD analysis. One of the most important components, the Reynolds-averaged Navier-Stokes solver, is described in detail. It originated from the Dawes solver with numerous enhancements. They include the use of the low speed pre-conditioned full Navier-Stokes equations, the addition of the Spalart-Allmaras turbulence model and an improvement of wall functions related with the turbulence model. The latest upwind scheme, AUSM, has been implemented too. The Dawes code has been rewritten into a multi-block solver for O, C, and H grids. This paper provides some examples to evaluate the effect of grid topology on the machine performance prediction.

Precisely Controlling Assembly Angle of Surface Tension Powered Self-Assembly for MEMS Microstructures

2007 ◽  
Author(s):  
Kai-Lin Pan ◽  
Yi-Lin Yan ◽  
Bin Zhou
Keyword(s):  
Surface Tension ◽  
Surface Energy ◽  
Self Assembly ◽  
Current Model ◽  
Three Dimensional ◽  
Design Parameters ◽  
Solder Paste ◽  
Surface Evolver ◽  
Final Assembly ◽  
The Relationship

How to integrate the microstructures which are made by various micro manufacturing methods into a functional system or device is the key to the application of MEMS technology. Solder self-assembly is based on surface tension with the properties of “self-organization”, low cost, batch processes and the compatibility with surface mount technology, which makes it be a challenging alternate technique. Solder self-assembly is based on the principle of surface energy minimization of molten solder material. During the process of minimizing the surface energy, surface tension can pull the horizontal hinged or hingeless plate up to a particular angle to achieve the minimal system energy. Finite element method is applied in this paper. MEMS self-assembly three-dimensional dynamic simulation model is developed by SURFACE EVOLVER. First, the model in this paper dynamically simulate the angle change of hinged plate during the process of evolvement of solder; second, the comparisons among the results from the current model and those from analytical two-dimensional model and three-dimensional static model are carried out; third, through Design of Experiments (DoE) with the application of the current model, the influences of design parameters such as pad size, pad geometry, and solder paste volume to the assembly angle are compared and discussed. Through changing the pad size, pad geometry and solder paste volume in SURFACE EVOLVER model, the corresponding final assembly angel from dynamic three-dimensional models are obtained. The relationship between design parameters to the assembly angle is concluded by the application of statistical analyses. The final angle can be controlled more effectively through synthetically optimize these parameters. It can provide effective guidance to the practical manufacturing of MEMS. Further research should focuses on the MEMS self-assembly experiment to intensively understand the relationship between the pad sizes, pad position, solder paste volume, hinge position, lock position and intermetallic compounds and the final assembly angle.

scholarly journals Design and analysis of flow rectifier of gas turbine flowmeter

2013 ◽  
Vol 17 (5) ◽  
pp. 1504-1507 ◽  
Author(s):  
Zhi-Fei Li ◽  
Zheng Du ◽  
Kai Zhang ◽  
Dong-Sheng Li ◽  
Zhong-Di Su ◽  
...  
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Computational Model ◽  
Pressure Distribution ◽  
Gas Turbine ◽  
Turbulence Model ◽  
Pressure Loss ◽  
Three Dimensional ◽  
Turbine Flowmeter ◽  
Good Agreement

Three-dimensional computational model for a gas turbine flowmeter is proposed, and the finite volume based SIMPLEC method and k-? turbulence model are used to obtain the detailed information of flow field in turbine flowmeter, such as velocity and pressure distribution. Comparison between numerical results and experimental data reveals a good agreement. A rectifier with little pressure loss is optimally designed and validated numerically and experimentally.

FEM Model for Pipeline Analysis of Ice Scour: A Critical Review

2004 ◽  
Author(s):  
Ibrahim Konuk ◽  
Abdelfdettah Fredj
Keyword(s):  
Current Model ◽  
Three Dimensional ◽  
Interaction Model ◽  
Design Parameters ◽  
Burial Depth ◽  
Line Pipe ◽  
Shell Elements ◽  
Temperature And Pressure ◽  
Pipe Geometry ◽  
Pipeline Design

This paper presents results from two different Finite Element (FE) pipeline ice-scour models employing pipe and shell elements that incorporate large deformations and metal plasticity. The main objective of this paper is to investigate the effects and implications of some of the main pipeline design parameters on the response of the pipeline determined by using Winkler models and soil displacements that are based on an empirical scour function commonly used in recent literature. The current model is two dimensional in terms of deformed pipe geometry and incorporates temperature and pressure stiffness effects. A detailed study of the soil displacements underneath and around the scour and a three-dimensional continuum based ice-soil-pipe interaction model is being presented in a different paper. The paper discusses the limitations and implications of the Winkler modeling and compares results obtained using different Winkler spring models. It illustrates the effects of pipe temperature (and pressure), pipe burial depth, and scour width. A comparison of pipe response using shell and pipe elements is also presented. This paper presents results from the FE models for a typical gathering pipeline. The pipe is taken to be a 16 inch diameter and 0.75 inch wall thickness API 5L X65 Specification line pipe.

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