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Ship's Log - Üsküdar
23/07/2015

Previous version of VMA97The Virtual Marine Arsenal is just a simple directory trying to compile some stuff (mostly software) which may be directly related to the naval architecture and marine engineering interests. The first version had been released in 1997. The active development has been stopped in June 2005.

After almost ten years later (see Picture.1) I decided for an update! It took about eleven weeks to build the new structure which is database driven this time and move the old data to the new site. The work was not that straightforward tough...

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kkLOmega Implementations in OpenFOAM

Ship's Log - Software
05/08/2015

A kkLOmega aolution around the ellipsk-kl-omega is a relatively new transition turbulence model. Since the version 2.1.0 this model has been implemented in OpenFOAM.  The model is based on the k-omega with an additional transport equation included to predict low-frequency velocity fluctuations that trigger transition in the boundary layer [1].

According to the notes in OpenFOAM source code, the latest version which is 2.4.0 as today has a significant update for the implementation of this turbulence model. Original note in the "kkLOmega.H (OpenFOAM-2.4.0.tgz)" is as follows:

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Evaluating OpenFOAM for the 6:1 Prolate Spheroid - First Stage

Ship's Log - Engineering
28/07/2015

Predicted Flow Around 6:1 Prolate SpheroidProlate spheroids can be considered as simple geometries. On the other hand the flow around a prolate spheroid at incidence offers a complex three-dimensional turbulent shear flows, featuring stagnation flow, a highly three-dimensional boundary layer, cross-flow separation, the formation and evolution of free-vortex sheets and stream-wise vortices etc.

Since these flow features are important in the area of aerodynamic and hydrodynamic design of vehicles, they have been the basis of much research over the years and many experimental studies have provided comprehensive data that reveals the salient physics of these kind of flows specially for 3:1 and 6:1 prolate spheroids. The 6:1 case has been most widely researched though.

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A 2D Preprocessor for Wing Sections: Construct2D

Ship's Log - Software
27/07/2015

Construct2D; a Preprocessor for CFD

Construct2D is an open source preprocessor for building the computational structured grids around wing sections. It may also work for other shapes though. Basically it works on 2D but also has a limited 3D capability by extruding the 3D grid on z axis.

The software has no GUI and written in Fortran. Indeed it does not need a GUI and works perfectly and efficiently via the command line. Construct2D can be compiled on different operating systems but I am using it on Linux and my experience is based on that OS only. On Linux the installation procedure is simple and smooth.

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Galvanic Corrosion and Series Table in Sea Water

Ship's Log - Materials
01/03/2002

Galvanic TableCorrosion is either chemical or electrochemical in nature. The distinction between chemical and electrochemical corrosion is based on the corrosion causing mechanism. Chemical corrosion is the direct result of exposure of a material to a chemical and is governed by the kinetics of chemical reactions.

Electrochemical corrosion is the dissolution of a metal through the oxidation process and can be defined as "degradation of a metal by an  electrochemical reaction with its environment". This phomena also known as galvanic corrision.

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