TY - JOUR
T1 - Prediction of nonlinear vertical bending moment using measured pressure distribution on ship hull
AU - Waskito, Kurniawan T.
AU - Kashiwagi, Masashi
AU - Iwashita, Hidetsugu
AU - Hinatsu, Munehiko
N1 - Funding Information:
The experiment for measuring the spatial distribution of unsteady pressure on the ship-hull surface was conducted as a collaboration work between Osaka University and Hiroshima University. Several students from both universities have been involved over a couple of years in this experiment and contributed to accurate measurement and analysis of large amount of data, for which the authors are grateful. This experimental work was supported in part by the Collaborative Research Program of Research Institute for Applied Mechanics (RIAM), Kyushu University, and in fact the measurement was carried out in the towing tank of RIAM. The authors are thankful to this support and help provided by Prof. Changhong Hu of RIAM and his colleagues. The present work was also partially supported with JSPS Grant-in-Aid for Scientific Research (A), Grant Number 17H01357 at Osaka University and also Grant-in-Aid for Scientific Research (B), Grant Number 18H01639 at Hiroshima University .
Publisher Copyright:
© 2020 Elsevier Ltd
PY - 2020/8
Y1 - 2020/8
N2 - Accurate prediction of wave loads on ships and floating structures is paramount in the structural design stage. Use of a segmented ship model is a common method to quantify the wave loads. Nevertheless, the value could be measured only at segmented sections. To obtain the wave loads at any longitudinal position and to account for nonlinear features in the wave loads more precisely, local quantities of the pressure on the whole ship-hull surface need to be measured along with ship motions in waves. In this paper, an unprecedented experiment using a bulk carrier model has been carried out to measure the spatial distribution of wave-induced unsteady pressure by means of a large number of Fiber Bragg Gratings (FBG) pressure sensors affixed on the whole ship-hull surface, and at the same time the wave-induced ship motions and ship-side wave profile have been measured. In order to see hydrodynamic characteristics in nonlinear and forward-speed effects on measured and analyzed results, some computations with the linear frequency-domain Rankine Panel Method (RPM) and the nonlinear Computational Fluid Dynamics (CFD) method solving the Reynolds-Averaged Navier-Stokes (RANS) equations are made. Favorable agreement is found for the pressure distribution and resulting vertical bending moment between the results of the experiment and corresponding numerical computations. Validation of the measured pressure distribution has also been made through a comparison of the wave-exciting force and moment between the two independent results obtained by integration of the measured pressure over the entire wetted surface of a ship and by direct measurement using a dynamometer. Very good agreement is confirmed in this case, too. As another validation for the wave loads, a comparative study is made with the benchmark test data of a 6750-TEU container ship used for the ITTC-ISSC joint workshop in 2014; which also demonstrates remarkable agreement. The present study may provide a new research technique, especially in the experiment, for predicting the wave-load distribution and for studying local hydrodynamic features in wave-related unsteady phenomena.
AB - Accurate prediction of wave loads on ships and floating structures is paramount in the structural design stage. Use of a segmented ship model is a common method to quantify the wave loads. Nevertheless, the value could be measured only at segmented sections. To obtain the wave loads at any longitudinal position and to account for nonlinear features in the wave loads more precisely, local quantities of the pressure on the whole ship-hull surface need to be measured along with ship motions in waves. In this paper, an unprecedented experiment using a bulk carrier model has been carried out to measure the spatial distribution of wave-induced unsteady pressure by means of a large number of Fiber Bragg Gratings (FBG) pressure sensors affixed on the whole ship-hull surface, and at the same time the wave-induced ship motions and ship-side wave profile have been measured. In order to see hydrodynamic characteristics in nonlinear and forward-speed effects on measured and analyzed results, some computations with the linear frequency-domain Rankine Panel Method (RPM) and the nonlinear Computational Fluid Dynamics (CFD) method solving the Reynolds-Averaged Navier-Stokes (RANS) equations are made. Favorable agreement is found for the pressure distribution and resulting vertical bending moment between the results of the experiment and corresponding numerical computations. Validation of the measured pressure distribution has also been made through a comparison of the wave-exciting force and moment between the two independent results obtained by integration of the measured pressure over the entire wetted surface of a ship and by direct measurement using a dynamometer. Very good agreement is confirmed in this case, too. As another validation for the wave loads, a comparative study is made with the benchmark test data of a 6750-TEU container ship used for the ITTC-ISSC joint workshop in 2014; which also demonstrates remarkable agreement. The present study may provide a new research technique, especially in the experiment, for predicting the wave-load distribution and for studying local hydrodynamic features in wave-related unsteady phenomena.
KW - CFD
KW - Fiber Bragg grating
KW - Nonlinearity
KW - Pressure distribution
KW - Rankine panel method
KW - Vertical bending moment
KW - Wave loads
UR - http://www.scopus.com/inward/record.url?scp=85086822823&partnerID=8YFLogxK
U2 - 10.1016/j.apor.2020.102261
DO - 10.1016/j.apor.2020.102261
M3 - Article
AN - SCOPUS:85086822823
SN - 0141-1187
VL - 101
JO - Applied Ocean Research
JF - Applied Ocean Research
M1 - 102261
ER -