Magnus...

Discussion in 'Boat Design' started by Sean Herron, Jun 15, 2006.

  1. Sean Herron
    Joined: May 2004
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    Location: Richmond, BC, CA.

    Sean Herron Senior Member

    Hello...

    Does anyone here know of any thing with regards to the 'Magnus effect' - the supposed drag and vibration of a spinning and forward moving shaft through water...

    Also same regarding fully enclosing the shaft in a complete or segmented shaft log and the benefits of doing so...

    This is in regards to high speed planing craft where the shaft exits the bottom of the boat and is supported by an I beam skeg before the prop...

    SH.
     
    Sean Herron, Jun 15, 2006
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  2. jehardiman
    Joined: Aug 2004
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    jehardiman Senior Member

    AOA of most shafts are too low to worry about magnus effect. AOA needs to be nearly 90 to generate any significant side force. Search for the Flettner Rotor ship for a discreption of the effect.

    Edit to add.... there is also a Renyolds effect in there too as I recall, so I think most shafts are too small and spinning too fast also
     
    jehardiman, Jun 16, 2006
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  3. Guillermo
    Joined: Mar 2005
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    Location: Pontevedra, Spain

    Guillermo Ingeniero Naval

    Have a look here:
    http://www.grc.nasa.gov/WWW/K-12/airplane/cyl.html

    Just guessing, I' think the magnus effect (kutta-joukowski's, in fact) shouldn't be significative for an spinning shaft moving through water with it axis aligned almost in the flow direction, should it?
     
    Guillermo, Jun 16, 2006
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