What is exactly the question? The measurements of an Eulerian acceleration dv/dt says only that the flow is unsteady, a fact that happens also in laminar flows behind a cylinder. The appearence of an unsteady behavior with a wider range of frequencies can be a symptom of the onset of turbulence. However, I cannot figure it out how that can be directly related to a turbulence model. The modelling is done on the non-linear term, that is the convective acceleration.

Hi Nazaruddin,

Please see the Thesis below titled:

Study of accelerating and decelerating turbulent flows in a channel

This thesis was undertaken by Akshat Mathur in 2016.

https://core.ac.uk/download/pdf/42605675.pdf

I hope it is of some use to you. All the best with your work.

Best Regards

Martin

H Filippo Maria Denaro.

Thanks for your comment. I think my question is clear. I'd like to to know if there exist in the literature, the explanation or correlation between flow acceleration/deceleration and the production of turbulence.

Bw, I will learn the thesis of Akshat Mathur sent by Martin McKie.

Have a nice time....

Hi Martin McKie.

Thanks for your info. I have downloaded the refererence. It looks great. I will learn it.

Have a nice time

The classic study of turbulence is generally introduced for ensemble/time averaging and the result is that the mean acceleration vanishes. In case of energy equilibrium, the flow is statistically steady. Only in the case of external forcing the Eulerian acceleration has a role also on the averaged quantities. You solve for the unateady part of the mean acceleration. However, the role of the unsteady field in the turbulence model appears only if you introduce the kinetic energy equations, do not forget that we model the unresolved part of the non-linear terms.

Clearly, a different issue is that you want to address the physical effect of the pointwise acceleration (like in DNS/LES) that is always present.

Hi Nazaruddin, no problem, happy to help.

Dear Researchers,

Have a nice weekend with your family....