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  1. #1
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    High Velocity Laminar Water Flow

    Where is high velocity laminar water flow always present? It really does happen. Why is this important? This should get interesting.
    No man can be both ignorant and free.
    Thomas Jefferson

  2. #2
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    The only place I can easily think of would be when there is no containment of the water.

    PHM
    --------


    Quote Originally Posted by WAYNE3298 View Post
    Where is high velocity laminar water flow always present? It really does happen. Why is this important? This should get interesting.
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  3. #3
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    I would say only in a length of straight pipe long enough to support it.

    You would need it for flow measuring stations, or for those fancy fountains that shoot water jets around for kids to play in! Lol!

  4. #4
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    Water falls, rain, and downfeed risers

    Maybe Domestic fixtures post aerator.


    Sent from my iPhone using Tapatalk

  5. #5
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    Also, in and out of the Compression tank.

    And all gravity systems, and those with no running pumps and missing flow controls.


    Sent from my iPhone using Tapatalk

  6. #6
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    Well, Wayne, are we close?

  7. #7
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    Thread Starter
    Some of you are getting close. I posted this question because it is commonly thought that velocity is the only factor in determining laminar and turbulent flow. Surprisingly there hasn't been much interest in this thread.
    Laminar flow is always present in a vena contracta.
    Now the rest of the question is why?
    No man can be both ignorant and free.
    Thomas Jefferson

  8. #8
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    I realize now that I was really picturing non laminar flow when I answered. No layering - which could only happen where there is neither containment friction or turbulence.

    So now that I looked up what a vena contracta is - tell me how / why there is no turbulence. And how high does the velocity have to be to completely overcome the effect of friction on flow?

    PHM
    -----------


    Quote Originally Posted by WAYNE3298 View Post
    Some of you are getting close. I posted this question because it is commonly thought that velocity is the only factor in determining laminar and turbulent flow. Surprisingly there hasn't been much interest in this thread.
    Laminar flow is always present in a vena contracta.
    Now the rest of the question is why?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  9. #9
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    Thread Starter
    You are hammering on it Poodle. The answer is in the boundary layer. More later after we get more comments.
    No man can be both ignorant and free.
    Thomas Jefferson

  10. #10
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    What is the dividing line for high velocity and non-high velocity?

  11. #11
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    Thread Starter
    In general turbulent flow is considered high velocity. I don't know if there is a better definition than that. Myself high velocity is when the velocity is higher than it should be under the conditions. For example a pump discharge pipe velocity can be OK at 10 FPS but I certainly wouldn't want that at the pump inlet.
    No man can be both ignorant and free.
    Thomas Jefferson

  12. #12
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    Where are the dividing lines between non-high velocity, high velocity, and excessive velocity? <g>

    PHM
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    Quote Originally Posted by TechmanTerry View Post
    What is the dividing line for high velocity and non-high velocity?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  13. #13
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    Quote Originally Posted by WAYNE3298 View Post
    Some of you are getting close. I posted this question because it is commonly thought that velocity is the only factor in determining laminar and turbulent flow. Surprisingly there hasn't been much interest in this thread.
    Laminar flow is always present in a vena contracta.
    Now the rest of the question is why?
    Neat thread Wayne. Fluid dynamics has been an interest of mine for the last couple of years.

    I think laminar flow is always present in a vena contracta due to the Bernoulli Effect. And yes it is laminar but turbulence does occur after the contracta, raising the Reynolds number slightly higher than that of the inlet, albeit briefly.

    I don’t have an answer to your original question. I can think of a few artificial and natural instances where high velocity laminar flow is present but none that have any significant importance.

    Looking forward to your answer!

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