With the development of ships towards large scale, high speed and light weight, ship hydroelastic responses and slamming strength issues are becoming increasingly important. In this paper, a time-domain nonlinear hydr...With the development of ships towards large scale, high speed and light weight, ship hydroelastic responses and slamming strength issues are becoming increasingly important. In this paper, a time-domain nonlinear hydroelasticity theory is developed to predict ship motion and load responses in harsh regular waves.Hydrostatic restoring force, wave excitation force and radiation force are calculated on the instantaneously wetted body surface to consider the nonlinear effects caused by large amplitude motions of ship in steep waves. A twodimensional(2 D) generalized Wagner model and a one-dimensional(1 D) dam-breaking model are used to estimate the impact loads caused by bow flare slamming and green water on deck, respectively;the impact loads are coupled with the hydroelastic equation in time-domain. Moreover, segmented model tests are carried out in a towing tank to investigate the wave and slamming loads acting on the hull sailing in harsh regular head waves and also validate the numerical results.展开更多
Segment sectional model tests are carried out to investigate the wind loading on middle pylon of Taizhou Bridge, which has complicated three-dimensional flow due to its feature of double columns. Through the force mea...Segment sectional model tests are carried out to investigate the wind loading on middle pylon of Taizhou Bridge, which has complicated three-dimensional flow due to its feature of double columns. Through the force measuring tests, aerodynamic force coefficients of every segment of the pylon columns have been obtained. It is found that the tested aerodynamic force coefficients are much smaller than those given by codes. The interference effects of aerodynamic force coefficients between columns of pylon are discussed. The results show that the interference effect is the most evident when the yaw angle is about 30 ° from transverse direction. This kind of interference effect can be described as diminutions in transverse aerodynamic force coefficients and magnifications in longitudinal aerodynamic force coefficients of downstream columns.展开更多
Since the amplitude and frequency of irregular waves change with time,great difficulties are brought for solving ship load responses in random waves.To take the effect of various frequencies of irregular waves into co...Since the amplitude and frequency of irregular waves change with time,great difficulties are brought for solving ship load responses in random waves.To take the effect of various frequencies of irregular waves into consideration in load responses of hull,the wave memory effect is necessary.A semi-analytical method is introduced for the time-domain retardation functions,and then a nonlinear hydroelastic method considering memory effect for ships in irregular waves is proposed.Segmented self-propelling model experiments of a container ship were carried out in a towing tank,a ship motion measuring device for self-propelling model test was designed.Whipping responses of the ship in regular and irregular waves are analyzed.Finally,the calculation results are compared with those measured by segmented model experiments,and the result indicates that the memory effect has little effect on load responses of ship in regular waves,but pronounced effect on results in irregular waves.Moreover,the presented method is reasonable for the prediction of ship load responses in irregular waves.展开更多
基金the Foundation for Distinguished Young Talents in Higher Education of Guangdong Province(No.2017KQNCX004)the Natural Science Foundation of Guangdong Province(No.2018A030310378)
文摘With the development of ships towards large scale, high speed and light weight, ship hydroelastic responses and slamming strength issues are becoming increasingly important. In this paper, a time-domain nonlinear hydroelasticity theory is developed to predict ship motion and load responses in harsh regular waves.Hydrostatic restoring force, wave excitation force and radiation force are calculated on the instantaneously wetted body surface to consider the nonlinear effects caused by large amplitude motions of ship in steep waves. A twodimensional(2 D) generalized Wagner model and a one-dimensional(1 D) dam-breaking model are used to estimate the impact loads caused by bow flare slamming and green water on deck, respectively;the impact loads are coupled with the hydroelastic equation in time-domain. Moreover, segmented model tests are carried out in a towing tank to investigate the wave and slamming loads acting on the hull sailing in harsh regular head waves and also validate the numerical results.
基金National Science and Technology Support Program of China ( No. 2009BAG15B01)Key Pro-grams for Science and Technology Development of Chinese Transportation Industry ( No. 2008-353-332-190 )National Science Foundation( No. 51008233)
文摘Segment sectional model tests are carried out to investigate the wind loading on middle pylon of Taizhou Bridge, which has complicated three-dimensional flow due to its feature of double columns. Through the force measuring tests, aerodynamic force coefficients of every segment of the pylon columns have been obtained. It is found that the tested aerodynamic force coefficients are much smaller than those given by codes. The interference effects of aerodynamic force coefficients between columns of pylon are discussed. The results show that the interference effect is the most evident when the yaw angle is about 30 ° from transverse direction. This kind of interference effect can be described as diminutions in transverse aerodynamic force coefficients and magnifications in longitudinal aerodynamic force coefficients of downstream columns.
基金Project(51509062)supported by the National Natural Science Foundation of ChinaProject(ZR2014EEP024)supported by the Shandong Provincial Natural Science Foundation,ChinaProject(HIT.NSRIF.201727)supported by the Fundamental Research Funds for the Central Universities,China
文摘Since the amplitude and frequency of irregular waves change with time,great difficulties are brought for solving ship load responses in random waves.To take the effect of various frequencies of irregular waves into consideration in load responses of hull,the wave memory effect is necessary.A semi-analytical method is introduced for the time-domain retardation functions,and then a nonlinear hydroelastic method considering memory effect for ships in irregular waves is proposed.Segmented self-propelling model experiments of a container ship were carried out in a towing tank,a ship motion measuring device for self-propelling model test was designed.Whipping responses of the ship in regular and irregular waves are analyzed.Finally,the calculation results are compared with those measured by segmented model experiments,and the result indicates that the memory effect has little effect on load responses of ship in regular waves,but pronounced effect on results in irregular waves.Moreover,the presented method is reasonable for the prediction of ship load responses in irregular waves.
