# Entries for July 2013

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## Q-criterion isosurfaces in MATLAB

Posted July 1, 2013 at 11:33 by sbaffini (NuTBox)

Let us suppose you have the following matrices:

x(nx,ny,nz): x coordinates of your grid

y(nx,ny,nz): y coordinates of your grid

z(nx,ny,nz): z coordinates of your grid

dudx(nx,ny,nz): x-wise derivative of x-wise velocity component

dudy(nx,ny,nz): y-wise derivative of x-wise velocity component
.
.
.
dwdz(nx,ny,nz): z-wise derivative of z-wise velocity component

This is, more or less, how i...
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## Basic finite volume tools

Posted July 1, 2013 at 11:29 by sbaffini (NuTBox)

http://rapidshare.com/files/1564297057/UFVMOM.rar

there is a basic MATLAB tool to handle unstructured finite volume grids (fluent .msh or .cas files) and to perform basic interpolations, gradient computations, plots etc. No actual FV computation is ever performed or implemented, however, the main structure of the code is clearly there.

GENERAL DESCRIPTION

The tool is actually a collection of functions, grouped by tasks...
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## LES in Fluent: channel flow test case

Posted July 1, 2013 at 11:12 by sbaffini (NuTBox)

A paper produced for a national conference. Some basic details of the LES in Fluent are covered, together with the main setup:

http://www.lamc.ing.unibo.it/aimeta2.../MEM-273-0.pdf
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## Lambda-2 criterion

Posted July 1, 2013 at 11:06 by sbaffini (NuTBox)

The lambda 2 criterion simply concerns the definition of the scalar lambda2 and how turbulent structures can be visualized by proper isosurfaces of lambda2 (like for the Q criterion). Hence, the real difference with the scalar Q is how you compute the scalar lambda2.

This is defined as the second (in magnitude) eigenvalue of the matrix:

where:

[LaTeX Error: Syntax error]...
Attached Files
 lambda2.c (2.6 KB, 188 views)
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## 3D Panel Method

Posted July 1, 2013 at 11:03 by sbaffini (NuTBox)

Some open/free 3D panel method tools:

APAME
http://www.3dpanelmethod.com/home.html

PANAIR (A502)
http://www.pdas.com/contents15.html (look for Panair - A502)

If you are looking for something more didactic, i suggest:

http://www.dept.aoe.vt.edu/~devenpor/aoe5104/

But it seems that the material is not available when the course is not active.
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