# Derivatives wrt Temperature

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 April 24, 2014, 19:33 Derivatives wrt Temperature #1 New Member   Deepak Kalaikadal Join Date: Feb 2014 Posts: 6 Rep Power: 11 How do I calculate derivative of a fluid property wrt temperature, like d(rho)/dT or d(viscosity)/dT? I am working on heat transfer in two phase systems where temperature gradients create vast differences in properties. Are there schemes to calculate these derivatives? I could find only divergence, laplacian and grad schemes. How do i incorporate a new discretization scheme for a derivative like above? I am currently using interFOAM with temeperature incorporated! Thanks! Last edited by kalaikdr; April 25, 2014 at 00:26. Reason: Add Information

April 25, 2014, 05:19
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 Originally Posted by kalaikdr How do I calculate derivative of a fluid property wrt temperature, like d(rho)/dT or d(viscosity)/dT? I am working on heat transfer in two phase systems where temperature gradients create vast differences in properties. Are there schemes to calculate these derivatives? I could find only divergence, laplacian and grad schemes. How do i incorporate a new discretization scheme for a derivative like above? I am currently using interFOAM with temeperature incorporated! Thanks!
You might have to extend the thermophysical model that you're using, to provide a function that calculates this derivative. Then you can use it in the equation you are solving. Depending on the model this can be an analytical or numerical derivative.

 June 5, 2014, 15:19 #3 New Member   Deepak Kalaikadal Join Date: Feb 2014 Posts: 6 Rep Power: 11 Thank you Chriss. But I ended up giving a constant value for the derivative. It was a very small magnitude anyway.