Study on Transom Stern Form Design Method Based on a New Theory

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1.Effect of Transom Stern Bottom Profile Form on Stern Wave Resistance(1)Effect of the transom stern bottom profile form:The concave stern bottom profile causes the lowest stern wave resistance at the lower ship speed range of F_<rI><3.1. The flat stern bottom profile causes the smallest stern wave resistance at the higher ship speed range of F_<rI>>3.1.(2)Relation between Stern Bottom Profile Form and Stern Wave Resistance:-At the lower ship speed rage of F_<rI><3.1, the stern bottom profile form controls the stern wave resistance mainly by controlling the real stern end immersion I_r.-At the higher ship speed range of F_<rI>>3.1, the stern bottom profile form controls the stern wave resistance mainly by controlling the remaining following wave height.-The concave stern bottom profile causes the smallest real stern end immersion I_r which is important at the lower ship speed range. The flat stern bottom profile causes the lowest remaining following wave height which is important at th … More e higher ship speed range.(3)Relative amount of the effect in hull resistance:Amount of the effect of the stern bottom form change is estimated to be significant in the powering for a full-scale ship.2.Effect of I_r(stern end immersion at running) on Stern Wave Resistance(1)Development of a method to estimate the effect of real stern immersion I_r on the stern wave resistance-An analytical method to estimate the stern wave resistance due to a transom stern taking I_r into consideration has been developed.-In the method, the stern wave resistance is treated as consisting of the four components : that due to the swbf, that due to the rfw, that due to acceleration of water flow at the stern end and that due to static water pressure change on the stern end plane.(2)Details of the effect of Iron the stern wave resistanceAnalysis of the model test results with above developed method has clarified the followings:-I_r relates with the stern wave resistance through its affecting the water flow velocity at the stern end viand the stern wave height 2_<r0>.-At the lower Froude number range of F_<rI><3.1:I_r/I is larger. The larger I_r/I brings larger resistance due to acceleration of water flow at the stern end C_<accs> and the C_<accs> occupies larger part of the stern wave resistance C_<sw>. I_r/I affects the stern wave resistance C_<sw> mainly through the C_<accs> The stern wave resistance is, therefore, almost decided by F_<rI> and I_r/I.-At the higher Froude number range of F_<rI>>3.1:I_r/I is smaller. The effect of I_r/I on the stern wave resistance is, therefore, not important. The stern wave resistance, the main part of which is the resistance due to the rfw C_<sfw>, is accordingly almost decided by F_<rI> and θ_e.3.Development of a Transom Stern Bottom Profile Form Design MethodBased on the results of the study described above, an theoretical method to design bottom profile form of the transom stern for such a ship that runs over a range of draft as a container ship has been proposed.4.Study Plan from NowWe would like to study on such a transom stern form of which stern wave resistance is equal to 0. Such a transom stern form is practically important and also necessary for study of transom stern form, because the stern wave resistance can be isolated from the residual resistance by using the transom stern form. Less