| Since the 21 st century,the human get the resources gradually from land to ocean,from the offshore to deep sea,the way to obtain the resources from the extensive to the intensive,which bring about that large scale side-by-side floating structures are used.The large size float-structure system is always consists of several modules with narrow gaps among them.Once the incident wave frequency is approximate to the resonant frequency of the narrow gaps,enormous increasing of wave run-up in the gaps and wave forces will be induced.The issue of gap resonance of the fluid between two side-by-side bodies has great influence on the safety of engineering operation,which has attracted many scholars’ interests in recent years.Most of the researches are always limited to the case of identical body draft and simple-geometriy body.Actually,the disparate ship load will result in different body draft and the shape of body is not the simple rectangular generally.Numerical and experimental investigation had been implemented to study the effect of body draft on the resonant characteristics of the fluid in the present article.Firstly,the traditional potential flow theory can over-predict the actual resonant wave height with fluid viscosity overlooked,even though it demonstrated the outstanding estimation of resonant frequency.An improved two-dimensional fully nonlinear time-domain numerical wave flume is developed to study the phenomenon of gap resonance in the present study.The computational domain is discretized with higher-order boundary element method.The incident regular waves are generated using the inner-domain sources so that the re-reflection at the input boundary can be eradicated.The fully nonlinear kinematic and dynamic boundary conditions are satisfied on the instantaneous free surface.In order to approximate the viscous dissipation due to vortex motion and flow separation,an artificial damping is set on the free surface in the gaps.Secondly,the two-dimensional physical model test was conducted in a wave flume at Dalian University of Technology.According to the comparison between the numerical result and experimental data,viscous coefficient in the gap could be defined.The numerical and experimental models are used to study the effect of body draft on the resonant characteristics of the fluid in the gap,the fluid viscosity,wave heights at the weather side and the lee-side etc.Meanwhile,the wave direction of propagation is also considered in the present study. |
