[Peifer]

Hello together,


I am working at the moment on the problem of a Laminar Buoyancy-Driven Cavity. There is a SU2-tutorial for example on this topic (https://su2code.github.io/tutorials/Inc_Laminar_Cavity/), but there are also a lot of papers online concerning this problem.


All have in common, that they use the ideal gas law in order to model the density and investigate the problem for rayleigh numbers of 1e3 to 1e6.

This leads to very low densities for air (~ 1e-3 kg/m³) and I'm wondering why these cases are investigated, which are quite far from the standard air density.


I would be very grateful if someone helped me on this topic.
Kind regards

[tas38]

Originally Posted by Peifer

Hello together,


I am working at the moment on the problem of a Laminar Buoyancy-Driven Cavity. There is a SU2-tutorial for example on this topic (https://su2code.github.io/tutorials/Inc_Laminar_Cavity/), but there are also a lot of papers online concerning this problem.


All have in common, that they use the ideal gas law in order to model the density and investigate the problem for rayleigh numbers of 1e3 to 1e6.

This leads to very low densities for air (~ 1e-3 kg/m³) and I'm wondering why these cases are investigated, which are quite far from the standard air density.


I would be very grateful if someone helped me on this topic.
Kind regards

I believe the typical range of Rayleigh numbers you listed are typical of buoyancy driven flows in liquids, e.g. water.

[FMDenaro]

Using non-dimensional form of the equation, no one will set air or any specific material as fluid .