• Journal of the Society of Naval Architects of Korea
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• v.56 no.2
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• pp.109-116
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• 2019

This paper carried out numerical analysis for estimating the propulsion performance of the model scale ONRT benchmark model of'Tokyo 2015 a workshop on CFD'. The method reflecting the scale effect of ITTC'78 method and form factor were used to compare the estimates of the effective wake ratio of full-scale. The numerical calculation was performed with Siemens's Star-CCM+, compared with IIHR model tests and the numerical analysis results of other research institutes, showing good agreement. In the case of an open stern and twin skeg ship, the validity of the ITTC'78 method can be confirmed by assuming that the effective wake ratio estimated from the numerical analysis results of model scale is similar to the effective wake ratio of full-scale.

• Bulletin of the Society of Naval Architects of Korea
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• v.26 no.4
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• pp.14-26
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• 1989

This paper describes the method of statistical analysis and its programs for predicting the ship's powering performance. The equation for the wavemaking resistance coefficient is derived as the sectional area coefficients by using the wavemaking resistance theory and its regression coefficients are determined from the regression analysis of the model test results. The equations for the form factor, wake franction and thrust deduction fraction are derived by purely regression analysis of the principal dimensions, sectional area coefficients and model test results. The statistical analyses are performed using the various descriptive statistic and stepwise regression analysis techniques. The powering performance prognosis program is developed to cover the prediction of resistance coefficients, propulsive coefficients, propeller open-water efficiency and various scale effect corrections.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.6
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• pp.497-506
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• 2019

Literature survey was conducted on the 2013 Interim Guidelines for determining the minimum propulsion power to maintain the manoeuvrability of ships in adverse conditions. The International Maritime Organization (IMO) Marine Environment Protection Committee (MEPC) documents related with the Guidelines were reviewed. Compatibility of the present Guidelines can be checked by two different levels: (Level 1) minimum power lines assessment and (Level 2) simplified assessment. The IHS (Information Handling Services) sea-web data on the bulk carriers and the tankers, which were built after 2000, were used to examine the Level 1 assessment. KVLCC2 was used to examine the Level 2 assessment. Regarding the Level 2 assessment, effects of the adverse weather conditions, the added resistance due to waves, the wake fractions and the thrust deduction factors were discussed.

• Journal of the Society of Naval Architects of Korea
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• v.31 no.1
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• pp.32-41
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• 1994

This paper presents the model-ship correlations based on model test results of 36 ships. All of model tests were conducted at KRISO towing tank The correlation factors $C_P,\;C_N,\;and\;C_{NP}$ are estimated by the ITTC Standard Method and compared with the results of another towing tank. In the 36 ships, the block coefficients of thirty ships are greater than 0.72. Nevertheless the comparison of factors is in good agreement. The corrections to the scale effect on wake fraction ${\Delta}{\omega}_c$ and roughness allowance $C_{Ac}$ are subject matter in practice. The correction formulae are proposed by functions of ship length and form factor. And the correction formula of resistance coefficient ${\Delta}C_{Fc}$ based on Townsis's hull roughness formula is presented.