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Approximation Schemes for convective term - structured grids - definitions

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(indicators of the local velocity direction)
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== indicators of the local velocity direction ==
== indicators of the local velocity direction ==
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<table width="100%"><tr><td>
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:<math>
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\phi_{w}=\sigma^{+}_{w}\phi_{W} + \sigma^{-}_{w}\phi_{P}
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</math>
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</td><td width="5%">(1)</td></tr></table>
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where <math>\sigma^{+}_{w}</math> and <math>\sigma^{-}_{w}</math> are the indicators of the local velocity direction such that
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<table width="100%"><tr><td>
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:<math>
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\sigma^{+}_{w} = 0.5 \left( 1 + \frac{\left|U_{w} \right|}{U_{w}} \right)
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</math>
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</td><td width="5%">(1)</td></tr></table>
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<table width="100%"><tr><td>
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:<math>
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\sigma^{-}_{w} = 1 - \sigma^{+}_{w} 
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</math>
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</td><td width="5%">(1)</td></tr></table>
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and of course
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<table width="100%"><tr><td>
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<math>
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\left( U_{w} \neq 0  \right)
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</math>
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</td><td width="5%">(1)</td></tr></table>

Revision as of 17:29, 29 September 2005

Here we shall develop a commone definitions and regulations because of

  • in different articles was used defferent definitions and notations
  • we are searching for common approach and generalisation

Usual using definition for convected variable


\boldsymbol{f}


\boldsymbol{\phi}

definition of considered face, upon wich approximation is applied

usually (in the most articles) west face of the control volume 
\boldsymbol{w} is considered (without loss of generality)

for which flux is directed from the left to the right

we shall define it as  \boldsymbol{f}

and convected variable at face as  \boldsymbol{\phi_{f}}

indicators of the local velocity direction

 
\phi_{w}=\sigma^{+}_{w}\phi_{W}	+ \sigma^{-}_{w}\phi_{P}
(1)


where \sigma^{+}_{w} and \sigma^{-}_{w} are the indicators of the local velocity direction such that


 
\sigma^{+}_{w} = 0.5 \left( 1 + \frac{\left|U_{w} \right|}{U_{w}} \right)
(1)
 
\sigma^{-}_{w} = 1 - \sigma^{+}_{w}
(1)

and of course

 
\left( U_{w} \neq 0  \right)

(1)
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