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adel2009 April 24, 2013 13:14

Partial differential equation in Field Functions
 
HELLO,
I want to Plot (Shear stress with Shear rate) in Non Newtonian fluid(Blood).
How could I write Shear rate in Field Functions?How could I write Partial differential equation in Field Functions?.Tanks
Shear rate (two Dimensional):
http://upload.wikimedia.org/math/8/a...80b7664f27.png

triple_r May 6, 2013 14:13

Hey,

You can use the grad() function to define velocity gradients. For example,

\gamma_{xy}=\frac{\partial u}{\partial y}+\frac{\partial v}{\partial x}

can be written as:

grad($$Velocity[0])[1] + grad($$Velocity[1])[0]

But I would suggest not using this method for the velocity gradients, and instead turning on the temporary storage option under the solver options (for example, under segregated fluid solver) and then using:

$$U_VelocityGrad[1] + $$V_VelocityGrad[0]

In my experience, this second method gives better results.

I hope this helps.


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