Evaluation of Resistance, Sinkage, Trim and Self-propulsion Predictions for KCS

Abstract

This chapter discusses the results of resistance predictions including trim and sinkage (the workshop case 2.1) and the results of self-propulsion predictions (the workshop case 2.5) for KCS. The resistance predictions for 6 different Froude numbers in trim and sinkage free condition were requested. The comparison error at the design speed (Fr = 0.26) is −0.2% and the standard deviation is 1.5% of the data value. The mean comparison error for all 6 speeds is 0.43% and the mean standard deviation is 2.48%. The increased error and standard deviation is caused by the results for low Fr simulation submissions. The submitted trim and sinkage also shows larger comparison error in low Fr region (Fr < 0.2). Self-propulsion results are reported with both towing force (FD) fixed and propeller revolution (rps) fixed. The participants using a body force propeller model based on potential theory selected FD fixed condition for self-propulsion and the participants who adopted actual propeller rotating simulation preferred rps fixed condition. The mean comparison errors of KT and KQ are 0.5 and −3.5% respectively. The standard deviations are 2.7 and 2.4% respectively. Self-propulsion parameters are slightly better predicted by body force models (FD fixed). However, local flow characteristics are better predicted by actual propeller rotating simulation (rps fixed).