Basic of fluid mechanics
 

Is turbulence typically a three-dimensional phenomenon, and does the analysis of 2D turbulence ignore the effects of turbulence in the z-direction?

Also, while the energy cascade generally progresses from large to small scales, what is the reason for the occurrence of inverse energy cascade in 2D turbulence?

Is this a characteristic feature of 2D turbulence?

Thanks :D

The 2D models for turbulence are generally in these categories:


- Statistically steady and homogeneous flow where RANS formulation is used
- Geophysical flows where the horizontal dimensions are much greater than the vertical one. However, the 3D effects are modelled in the turbulence model.


Solving the 2D model, the fundamental effect of the stretching term is no longer present. Therefore, the energy transfer is different.