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How Does Operating Conditions Effect?

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Old   March 23, 2016, 10:59
Default How Does Operating Conditions Effect?
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Hello all.

In any case how does operating boussiesq temperature and operating density effect solution? I mean, what does happen if only operating conditions different between same cases?

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Old   March 23, 2016, 15:53
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The difference between two simulations run with different operating temperature (and operating density) is the density itself.

With the boussinesq approximation, the density is assumed constant (the operating density). If you change the operating temperature you change this density, which may affect your flow field. In other words, if you imagine you are running a constant density simulation and then change the density, this is the same effect as you would have if you changed the operating density in a simulation using the boussinesq model. This doesn't change the nominal buoyancy force but you can have a different heat capacitance which can affect the temperature field also and that indirectly affects the buoyancy force. Essentially, you have a different Reynolds/Rayleigh and Grashof numbers because of the different density.
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Old   March 23, 2016, 16:13
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Quote:
Originally Posted by LuckyTran View Post
The difference between two simulations run with different operating temperature (and operating density) is the density itself.

With the boussinesq approximation, the density is assumed constant (the operating density). If you change the operating temperature you change this density, which may affect your flow field. In other words, if you imagine you are running a constant density simulation and then change the density, this is the same effect as you would have if you changed the operating density in a simulation using the boussinesq model. This doesn't change the nominal buoyancy force but you can have a different heat capacitance which can affect the temperature field also and that indirectly affects the buoyancy force. Essentially, you have a different Reynolds/Rayleigh and Grashof numbers because of the different density.
Then, if I use ideal gas model or polynomial constants for my case, different operating conditions does not effect my solution? They behave like something starting point? Am I right?

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