Thank you very much Dudley J Benton

Yes, I agree with you. In some discussions about the transition flow, it seems that there are still many differences of opinion or theory. So we have concluded that this flow is still a mystery. Even the transition theory, proposed by Schlichting, apparently does not have enough solid evidence. T-S waves apparently do not appear in flows that do not have a pressure gradient. The result can be quite fatal, especially in estimating flow regimes on surfaces that are not too long.

In the present discussion here we try to talk about the effect of free-stream turbulence on the transition. I believe that the free-stream turbulence has a significant effect on the occurrence of transition flow. Naturally, a transition process is a process that is very vulnerable to interference and is not yet stable. Therefore the transition is an unstable flow. This flow condition is certainly more sensitive to disturbances. Thus, disturbances in the form of free-stream turbulence has the potential to affect the process of transition from laminar to turbulent flow. In my opinion, the free-stream turbulence will tend to accelerate the transition to turbulent flow. However, I do not yet know whether my theory can be justified. This is one of the aims and objectives of the discussion. T

I look forward to your responses and opinions from all the scholars here.

Thanks you.

Dear scholars, please give your comment for this topic.

Thank you very much.

There is a lot of disagreement over what characterizes free stream turbulence. If someone tells you there isn't, then they've just dismissed their colleagues who don't agree with them or they're not aware of the decades-long debate. I try to appreciate the differing views and find commonality. Some insist that the "trip" initiates within the boundary layer, while others insist that it comes from the free stream into the boundary layer. I suspect it's a combination of the two. Even simple experiments with unstable objects yield differing results, hence the study of chaos. The transition from laminar to turbulent is not literally "chaotic," which often degenerates into an argument over semantics. Critical Reynolds numbers for pipe flow and flow over a flat plate are just observed averages. Even the Moody chart shows a transitional region, rather than a single value. Hoping to accurately nail down a condition or transitional point with CFD software, is not a wise quest. When CFD results come close to laboratory measurements for such a thing, it's cause to celebrate. Never forget that every turbulence model and calculation leads back to some experimental result and is, therefore, necessarily an approximation.

Thank you very much Dudley J Benton

Yes, I agree with you. In some discussions about the transition flow, it seems that there are still many differences of opinion or theory. So we have concluded that this flow is still a mystery. Even the transition theory, proposed by Schlichting, apparently does not have enough solid evidence. T-S waves apparently do not appear in flows that do not have a pressure gradient. The result can be quite fatal, especially in estimating flow regimes on surfaces that are not too long.

In the present discussion here we try to talk about the effect of free-stream turbulence on the transition. I believe that the free-stream turbulence has a significant effect on the occurrence of transition flow. Naturally, a transition process is a process that is very vulnerable to interference and is not yet stable. Therefore the transition is an unstable flow. This flow condition is certainly more sensitive to disturbances. Thus, disturbances in the form of free-stream turbulence has the potential to affect the process of transition from laminar to turbulent flow. In my opinion, the free-stream turbulence will tend to accelerate the transition to turbulent flow. However, I do not yet know whether my theory can be justified. This is one of the aims and objectives of the discussion. T

I look forward to your responses and opinions from all the scholars here.

Thanks you.

Dear scholars,

Please give your reply.

Thank you very much...

I agree with your assessment and especially the susceptibility to disturbances. Practical experiments (in the field) often differ from academic ones (in a laboratory) by such things as vibration and irregularities. We can learn from both, even though it is often difficult to quantify the differences. I encourage you to continue pursuing this matter. You must put "tufts" on your car plus every engineer must see the movie Ford vs. Ferrari

Dear other scholars, please give your opinion here. We need it.

Thank you very much.

Dear respected colleagues and scholars. Please participate in the discussion and give your comments.

Thank you very much.