Learning Forum

[Waruna Maddumage]

Hi,

I'm trying to define viscosity of a liquid as a temperarture dependent polynomial function in Fluent.

I plotted the experiment data in Excel to get the trend line and polynomial equation. Below is the Excel polynomial graph and function. 

When I tried to enter the coeffients in Fluent to define viscosity, I get a completely wrong graph. 

Below is the graph I got from Fluent to the coeffients from the above equation.

Can someone pls tell me what I am doing wrong here? 

Thanks in advance, 

Best regards,

Waruna

 

[abhnv11295]

I would suggest you to kindly cross-check manually with the coefficients you have obtained via Excel. 

[Waruna Maddumage]

Thanks, your suggestion helped. 

Increasing the significance of the coefficients solved the issue. Using Matlab polyfit is the better choice. 

[Amine Ben Hadj Ali]

I came across similar issues several times. The same reason: the significance / number of digits / accuracy.