CFD codes for surface piercing propellers

Discussion in 'Surface Drives' started by aziziyeng, Jul 10, 2009.

  1. aziziyeng
    Joined: Jul 2009
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    aziziyeng Junior Member

    I need some information about CFD codes for surface piercing propellers. Can you help me?
     
  2. marshmat
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    marshmat Senior Member

    Welcome aboard :)

    And, yeouch! CFD of a surface-piercing prop.... just thinking about it makes my head spin.

    I have no idea how to do such a complicated model; indeed, I suspect there are only a handful of people who do. Two-phase flow is enough of a pain as it is, without adding turbomachinery and a dynamically changing grid to the situation.

    Now, if you're looking to specify a surface prop, as opposed to doing an actual CFD simulation of the flow patterns surrounding one, there are established benchmarks for doing that....
     
  3. ubik
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    ubik New Member

  4. brunello
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    brunello Junior Member

    Flexitab, in Italy, has been conducting an in depth research work on the subject and got very good results. If you drop an e-mail to mr. Ciro, the engineer in charge of the work, he will be glad to share knowledge. The test were made on a family of five bladed surface props, specially designed for low speed applications (displacement), which had been previously tested in the Genoa cavitation tunnel and subsequently in the naples tank testing facility. Numerical results matched quite well the experimental lab test. Regards, Brunello
     
  5. Leo Lazauskas
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    Leo Lazauskas Senior Member

    Were they made to match the results well by a choice of empirical constants? As someone once said, "Give me two free parameters and I can fit a curve to my grandmother's fat ***".

    I've seen 6 free parameters and more in some CFD codes. :)

    Cheers,
    Leo.
     
    Last edited: Jan 22, 2010
  6. ciro
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    ciro New Member

    semi-submerged propeller: CFD simulation

    Dear Aziziyeng,

    a CFD simulation of a semi-submerged propeller is very hard because you have to solve some different “big problems” simultaneously: rotating domains and multiphase flowfields.
    In order to solve them, in Flexitab, we developed some specific routines inside one of the most common CFD software. Without them we had always overflow!!
    We are studying a five bladed propeller that has been previously tested into a naval tank.
    We compared the experimental data with the numerical ones and the results, till now, are encouraging: we found only a small difference between them.
    If you have some specific question, I’ll be glad to help you.
    Regards
    Ciro
     
  7. sottorf
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    sottorf member

    Dear Ciro,
    that is very interesting. I was recently involved in a low speed application using an Arneson drive (19m boat, 22 knots) and the system worked quite well. Initially there was massive vibration problem with a 4 bladed prop, which disappeared with a 5 bladed version. I therefore fully agree with you that there is a good future in surface drive applications for low speeds.

    A colleague and I have been doing some research into applying CFD codes to surface propellers. I am interested to know which code you have used and if you can help us to try and get a working model using Fluent.

    Also do you have any experimental data you can make available that can be used for design?
     
  8. softwaretool
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    softwaretool New Member

    interesting.
    thanks you so much.
     
  9. ciro
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    ciro New Member

    Dear Sottorf,
    we are very confident in surface drive applications. Still now we are studying theese kind of propellers and their possible applications using numerical codes and also through naval tank tests.
    If you want you can visit our web site (http://www.flexitab.com/flexidrive.htm and http://www.victory.it/modellazione3d.html) where there are some images and videos about our studies.

    You can also watch a video about a naval tank test carried out at the University Federico II in Naples, at the link below:

    http://www.youtube.com/watch?v=7-UVMGc76O0

    As you can see we have spent a lot of time and resources for the simulations in the naval tank in order to obtain experimental data that are protected by trade secret. I'm sorry but I can make them available.

    About CFD simulation, we are Ansys CFX users and we developed a particoular (and quite complicated) mathematical model for this kind of software.
    I used Fluent during my University studies and I'm confident that a mathematical model could be developed with some differences in the definition of the UDF (if i remember well in fluent you have to compile some C++ routine).

    Have you already tried to develope something about propeller simulation in Fluent (mono and/or multiphase flowfield)?

    If yes, what kind of problem do you have?

    Regards

    Ciro
     
  10. PetterM
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    PetterM Senior Member

    What propulsive efficiency did you get at this speed?

     
  11. aziziyeng
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    aziziyeng Junior Member

    Dear Ciro,
    I saw your web site. available picture for SPP modeling shows your minuteness in modeling of complicated physics of phenomenon.
    I used Ansys CFX and made a preliminary model for a propeller in partially submerged condition using rotating domain and multiphase flow. I used a tight cylindrical rotating domain around the propeller connected to the blades and could to see ventilation around propeller to some extent. but water spray behind the propeller and other details related to blades strike with surface have not been modeled yet. Do you have any suggestion to me for bringing these more details in my simulation?
    Can you explain more about your extra mathematical modeling and developed routines? exactly for solving which problems these routins was added to your CFX simulation. I'm going to start a serious academic research in this subject and your hints will be very helpful for me.Thanks alot
    Best regards
     
  12. Lennart_Berghul
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    Lennart_Berghul New Member

    CFD of Surface Piercing Propellers

    For a Customer named Stormfageln www.stormfagel.se
    I did a CFD using Ansys CFX 11.0 , it includes air entrainment and cavitation transformation. it corresponds to the measured thrust and I also used the
    well known series of the Kamewa propeller in modelscale as Validation
    the simulation was presented at FAST-09 which was held in Athens in october -09
    I have not a link at the moment but you can request it from me
    lennart.berghult@semcon.com
    /Lennart
     
  13. yipster
    Joined: Oct 2002
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    yipster designer

    i am by no means an expert but find this very interesting and here my request if no cost is involved to read your simulation results, has Paul Kamen seen this drive?
     
  14. Lennart_Berghul
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    Lennart_Berghul New Member

    email me

    if you email me I will see to that you get the published results
    lennart.berghult@bluewin.ch
    I have read things ny Paul Karmen but I have had no contact regarding Stormfageln
     

  15. yipster
    Joined: Oct 2002
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    Location: netherlands

    yipster designer

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