Fluid Mechanics, The Boundary Layer; SAFL Film No. 56

This Video was made by the staff of the St.Anthony Falls Laboratory of the University of Minnesota under the direction of Lorenz G. Straub, Lab Founder, and Director from 1938 through 1965. 30 minutes, Audio is very quiet. This is the video you need for U of MN CE 3502.
Film No. 56 FLUID MECHANICS - THE BOUNDARY LAYER. Originally one 1100-ft. reel, 30 minutes, Kodachrome, sound. $9.50 per showing,
A series of demonstrations pf physical principles with four main sequences: 1) boundary layer on a flat plate, 2) boundary layers and pipe flow, 3) separation of the boundary layer, and 4) roughness in the boundary layer. The picture is planned to be used as a summary after lectures on the subject and is not intended to substitute for regular class lectures. (Produced under National Science Foundation grant.) 1961.

[@unverozkol]

Critical Reynolds number is mentioned as 1e5. In modern books it is given as 5e5.

[@carmelpule6954]

This is an interesting video that shows the details of what goes on unnoticed by the human eyes. Although analogies never do really pick up all the equivalent behaviour it would be useful to say that what goes on in the boundary layer is somewhat equivalent to what goes on at the surface of the sea or a large lake when a breeze blows over the surface. When the breeze is of very low velocity, the surface of the lake is made to move and if dead leaves from trees are floating on it, the leaves would be seen moving downwind and yet the surface of the sea or lake would still be smooth. There will be a velocity gradient between the surface or the lake and the bottom of the lake. In such conditions the surface of a lake may be seen and described by "shimmering in the moonlight" as that is all that is expected of the small wavelets produced by a breeze.
When the breeze changes to a wind there may appear to be more disturbances and the surface of the lake would have some undulations of substantial height but in general the surface waves would still be plane. In stormy conditions, the wind that hits the waves would itself be modified and so the momentum and energy in the air have different vectors and would now have a churning effect on the surface of the sea or waves. The junction between sea and air would be so complex as it would not be a case where the viscous forces would be the ones present but the energy in the air particles would disturb the water while the energy in the water would disturb the air and so this would churn the sea, not as a steady state continuous flow but as a periodic zones of varying air pressure to which the sea and the peaks of the generated waves would start rolling on each other and at higher velocities the energy in the air would shear the peaks of the waves to really set up a turbulent situation, with sea spray reaching high into the air above and the air churning the sea so much that great depths even all type of vortexes are created in both the sea and in the air , vortexes which have their axis parallel with the flow or those across the flow where rolling waves may be treated as such. It would not be far fetched to say that the disturbance in air and sea would include all the vortexes that one calls typhoons where complex circulations and high and low pressure zones would be created without any predictable order apart from the rules of the state conditions at a particular space in particular times.
The tranquil characteristics of viscosity and the different moods of any fluid with mass, when vectored momentum and energy are present in it, their engagements and behaviour does make grounds for a great numbers of interesting marriages, especially when their abode contains too many corners and angled sharp edges, where vortexes can be generated, hide and churn and mix up the conditions in an unprecedented manner!

[@avneeshnathan4978]

That my friend is one hell of an explanation. Thanks :)

[@hariprasath2837]

Any here because of varun pathak sir

[@Albino382]

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