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Experimental method for calculation drags reduction in air cavity boat

Fakhraee, A ; Sharif University of Technology | 2007

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  1. Type of Document: Article
  2. Publisher: 2007
  3. Abstract:
  4. The search for higher ship speeds and better propulsive performance has resulted in many performance enhancement techniques. One technique is to introduce an air film along the bottom of the hull to reduce skin friction drag. The air film system opens many possibilities for using designs with larger payloads such as barges and tankers, as well as catamarans with larger deck space which otherwise are not attractive because of their higher propulsion power. Although reducing hull drag by air injection was proposed in the beginning of this century, it still remains to be fully exploited. In this thesis, two models are used to do the experiments. The first one was a simple catamaran model and the other was a catamaran with air cavity injection under its bottom. Dead rise angle was fixed to 23 degree during both model tests. As a contribution this paper briefly reviews the application of bottom air film, as well as tow tank and trial results. The extent of the performance improvement is illustrated in plots of Drag/Displacement versus Froud number It is shown that while the air injection equipment adds appendage drag to the barge hull, the bottom air flow results in a net drag reduction of 12.5-23% in model tests
  5. Keywords:
  6. Air cavity ; Air films ; Air flow ; Air injection ; Catamaran ; Experimental methods ; Froud number ; High speed crafts ; Model tests ; Performance enhancements ; Performance improvements ; Propulsion power ; Propulsive performance ; Rise angles ; Ship speed ; Skin friction drag ; Tow tanks ; Barges ; Cavitation ; Drag reduction ; Fire fighting equipment ; Sailing vessels ; Tankers (ships) ; Hulls (ship)
  7. Source: 9th International Conference on Fast Sea Transportation, FAST 2007, Shanghai, 23 September 2007 through 27 September 2007 ; 2007 , Pages 278-285 ; 9781622764129 (ISBN)
  8. URL: https://www.researchgate.net/publication/293103668_Experimental_method_for_calculation_drags_reduction_in_air_cavity_boat