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      Following the above discussion, the model having the shape in Figure 2 was chosen. The radar mast
      and on-deck pipe system were excluded and bow part of the hull was replaced with a vertical prism.



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                          Figure 2: Model Used in the Parametric Study


      3  PARAMETRIC STUDY
      3.1 Parameters

      Among the elements that are expected to influence the flow field around the funnel, deckhouse height,
      funnel height and funnel position were chosen as parameters. Their definitions are shown in Figure 3.
      Variations of parameters are also listed in Figure 3, where the abbreviations DH, FH and FP stand for
      deckhouse height, funnel height and funnel position respectively. These abbreviations mean the same
      throughout this paper. Deckhouse height varies with the step of 2 m and DH2 has the same deckhouse
      height as the original model. Funnel height variation follows the way that the ratio of funnel height to
      deckhouse height changes with the step of 0.15. The original value of the funnel height to deckhouse
      height ratio is 1.307, so the closest case to the original model is FH3. Concerning the funnel position,
      three cases are applied and the funnel position of FP2 is the same as the original model. Following
      these variations, 60 cases were produced.




                                              Case  Original  DH1  DH2  DH3  DH4
                                              DH    21.5   19.5  21.5  23.5  25.5


                                              Case  Original  FHl  FH2  FH3  FH4  FH5
                                             FWDH  1.307  1.00  1.15  1.30  1.45  1.60


                                              Case  Original   FPl   FP2   FP3
                                               FP     7      5     7       9

                           Figure 3: Parameter Definition and Variation
      3.2 Calculation

      3.2. I  Calculation domain and mesh
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