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**Streamwise Normal Stress**
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::
Streamwise normal stress = {yes | no}
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**Description / Usage**
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The stream-wise normal stress, :math:`T_{tt}`, is defined as tt: :math:`\tau`, where t is the unit tangent vector
to the streamlines computed as v ⁄ :math:`\mid` v :math:`\mid` and :math:`\tau` is the deviatoric part of the dissipative stress
tensor,
.. figure:: /figures/320_goma_physics.png
:align: center
:width: 90%
associated with the Navier-Stokes equations. This variable is called SNS in the output
EXODUS II file.
The permissible values for this postprocessing option are
======== ===============================================
**yes** Calculate the stream-wise normal stress.
**no** Do not calculate the stream-wise normal stress.
======== ===============================================
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**Examples**
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Following is a sample card:
::
Streamwise normal stress = yes
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**Technical Discussion**
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As of 2/9/02 this function is computed with the based viscosity, and not the strain-rate
dependent viscosity as might be the case for viscosity models other than *NEWTONIAN*
(see *Viscosity* card).
..
TODO - Line 17 contains a photo that needs to be written as an equation.