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Old   March 13, 2024, 07:32
Default Ansys expression
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AHMED KANDIL
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Hello everyone
I'm trying to write an expression for inlet temp with time and this is my expression
0.016[S]*t^6-0.2703[S]*t^5+1.6363[S]*t^4-4.3126[S]*t^3+5.1111[S]*t^2-1.6118[S]*t+298.26[S]
but i get this error
All arguments should have the same dimensions as the first argument [kg^-1 m^-2 s^9 A^2] but argument 2 has dimensions of [kg^-1*m^-2*s^8*A^2]
how i can solve this problem
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Old   March 13, 2024, 11:13
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Rohan sharma
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You have to adjust the units for all components.
Hence you need adjust the units of each constant.
I am not sure what is this unit [S]
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Last edited by rohansharmafree; March 13, 2024 at 12:21.
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Old   March 13, 2024, 13:57
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Ryan Renaud
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Hi Ahmed,

This thread belongs in the ANSYS Fluent forum, not the CFD freelancers forum.

That being said... Your problem seems to be your units. You mentioned you're specifying temperature, so if you're working with SI units then every term should be in Kelvin (K).

Your formula seems to be a polynomial with different exponents of time - the unit of each coefficient should be K*s^(-n) where n is the power of the temperature term it is being multiplied with and s is seconds. For example, 0.016 * t^6 - here, 0.016 should have units of K*s^(-6) as this will make that whole term equal Kelvin.
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Old   March 15, 2024, 07:37
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AHMED KANDIL
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Hi RavingRaven
Thank you for your reply and i will do this..
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Old   March 15, 2024, 07:39
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AHMED KANDIL
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Hi rohansharmafree
Thanks ...
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