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Base Ventilated Super-Cavitating Hydrofoils for Fast Ferry Motion Control

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Base Ventilated Super-Cavitating Hydrofoils for Fast Ferry Motion Control

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    1. Base Ventilated Super-Cavitating Hydrofoils for Fast Ferry Motion Control Bryce Pearce Research Student Dr Paul Brandner - Supervisor

    2. Ventilated & Supercavitating Foils Non-attached types of cavities are known as super-cavities, I.e. those where the cavity closure happen off the foil itself. The lower figure shows a typical design of super cavitating hydrofoil. The upper figure is an example of a base ventilated foil where again the cavity closes off the foil surface. Both these foil shapes are unsymemetrical, and produce lift in one direction only.Non-attached types of cavities are known as super-cavities, I.e. those where the cavity closure happen off the foil itself. The lower figure shows a typical design of super cavitating hydrofoil. The upper figure is an example of a base ventilated foil where again the cavity closes off the foil surface. Both these foil shapes are unsymemetrical, and produce lift in one direction only.

    3. [Elms Australia] Patent Improved Hydrofoil device

    4. Intercepted Hydrofoil with Base Ventilated Cavity Symmetric foil section with an interceptor or fence attached to the trailing edge to produce lift. A cross section of the wedge foil showing an approximate cavity shape (NTS).A cross section of the wedge foil showing an approximate cavity shape (NTS).

    5. Some Definitions

    6. Flow region near Interceptor

    7. 2-D Panel Method Numerical prediction of Cavity Shape & Hydrodynamic characteristics. Non-linear method A numerical code has been developed based on a 2D potential flow method published by Lee, Kim & Lee, which enables the cavity shape and hence the hydrodynamic lift acting on the foil to be predicted. This will be utilized in optimising the shape of the foil section.Each of the curves sows the iterations that the code goes through converging to give the cavity shape.A numerical code has been developed based on a 2D potential flow method published by Lee, Kim & Lee, which enables the cavity shape and hence the hydrodynamic lift acting on the foil to be predicted. This will be utilized in optimising the shape of the foil section.Each of the curves sows the iterations that the code goes through converging to give the cavity shape.

    8. Ramp Shape

    9. Ramp Shape

    10. Constant T.E. angle / variation in Chord

    11. Some More Definitions

    12. Constant T.E. angle / variation in Chord

    13. Constant Chord / variation in T.E. angle

    14. Super-Cavitating Hydrofoils (with ramp) Some preliminary numerical results

    15. Foil & Cavity Nomenclature

    16. Foil Section Parameters TCR foil thickness to chord ratio HCR ramp height to foil chord ratio HLR ramp height to length ratio g te foil foil trailing edge angle g te ramp ramp trailing edge angle

    17. Base Foil - 1xx Series Single term nth - order Polynomial

    19. Intercepted Foil Numerical Model

    20. Results: Cavity Shape

    21. Results: Cavity Shape

    22. Results: Cavity Shape

    23. Results: Cavity Shape A non-linear relation Only weakly effected by incidence

    24. Results: Cavity Shape

    25. Another Definition

    26. Results: Pressure Distribution

    27. Results: Pressure Distribution

    28. Results: Pressure Distribution

    29. Results: Hydrodynamic Forces

    30. Results: Hydrodynamic Forces

    31. Conclusions & Further Work

    32. Questions? With ventilated cavityWith ventilated cavity

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