PBL Velocity Profile: Sinusoidal Variation w/ Height

AI Thread Summary
The discussion centers on the sinusoidal variation of the planetary boundary layer velocity profile with height, as depicted in a figure from "Fluid Mechanics" by Kundu and Cohen. There is confusion regarding the absence of a clear explanation for this undulation in the text, especially since such variations are not typically observed in flat plate boundary layer profiles. The conversation also references the Ekman boundary layer and its characteristics, particularly the "Ekman spiral," which is relevant to understanding the velocity profile's behavior. Participants express a need for clarity on the specific figure and its implications, highlighting the complexity of atmospheric boundary layer dynamics and the importance of visual aids in comprehending these concepts.
MOHAMMAD UMAIR
Messages
4
Reaction score
1
Why does the planetary boundary layer velocity profile shows a sinusoidal variation with height?
Reference: Fig:14.10 Page 576 Fluid Mechanics - Kundu and Cohen 2nd edition
 
Earth sciences news on Phys.org
I don't see any mention of sinusoidal variation with height in the text ? Perhaps you have misinterpreted what is shown in fig 4.10 (b) ?

I think that the general topic is explained quite well by the author .

Please post new questions if you have any specific problems .
 
Last edited by a moderator:
Nidum said:
I don't see any mention of sinusoidal variation with height in the text ? Perhaps you have misinterpreted what is shown in fig 4.10 (b) ?

I think that the general topic is explained quite well by the author .

Please post new questions if you have any specific problems .
Thanks Nidum for your reply. I know that the general topic is explained quite well in the text but the author has presented the boundary layer velocity profile in the figure without explaining why there is an undulation of the velocity profile with height. You won't find such undulations in the general boundary layer velocity profiles on a flat plate.
 
Last edited by a moderator:
jim mcnamara said:
My apologies if I am making a mess of this question. But. Is Figure 1 in the linked pdf file what you are talking about?

people.atmos.ucla.edu/jcm/turbulence_course_notes/planetary_boundary_layers.pdf

interesting article, thanks :smile:
MOHAMMAD UMAIR said:
Why does the planetary boundary layer velocity profile shows a sinusoidal variation with height?
Reference: Fig:14.10 Page 576 Fluid Mechanics - Kundu and Cohen 2nd edition
I don't have access to that article/book ... it would be good for you to copy and paste the section or if you cannot, scan it or at bare minimum type out the paragraph or two that you are referring to, so that we are all on the same page

As a result, I have no idea which boundary you are referring to ??
Moho ?, upper/lower mantle ?, mantle/outer core ?
MOHAMMAD UMAIR said:
I know that the general topic is explained quite well in the text but the author has presented the boundary layer velocity profile in the figure without explaining why there is an undulation of the velocity profile with height. You won't find such undulations in the general boundary layer velocity profiles on a flat plate.

assuming you are referring to one of my listed ones, and probably the Moho boundary,

Why would you expect to ? the Earth isn't flat and nor are the layers and their boundariesDave
 
Thank you all for showing your keen interest in answering the question I've posed. Davenn I am reffering to the Ekman boundary layer profile that you have in your lecture notes on page number 24 figure15 a.
 
  • Like
Likes jim mcnamara
jim mcnamara said:
I believe he is talking about this, which is why I am cautious, cannot see the book he referenced. (meteorology, laminar flow (fluid dynamics) and more intricacies):
https://en.wikipedia.org/wiki/Planetary_boundary_layer

There is a really great graphic there.

ohhh, we are going up, not down, I guessed that wrong ... will do some reading :smile:
 
MOHAMMAD UMAIR said:
Thank you all for showing your keen interest in answering the question I've posed. Davenn I am reffering to the Ekman boundary layer profile that you have in your lecture notes on page number 24 figure15 a.
Are you asking why the "Ekman spiral" spirals?
 

Similar threads

Replies
1
Views
4K
Back
Top