Study Of Wave Impact On Column-slab Combined Structure Based On SPH Method

As the energy development is gradually changing from land to deep sea,offshore platforms are more widely used in the field of marine energy development.When wave impact occurs at the bottom of transparent buildings,the impact mechanism is very complicated.Caused by the instantaneous impact loads,the safety and stability of structure will be greatly influenced,so it is very important to study the wave impact process.In order to simplify the semi-submersible platforms,a column-slab combined structure is established as the research model.Based on the SPH method,numerical simulations are carried out to conduct the wave impact research.The processes of the wave impacting the horizontal plate and column-slab combined structure are investigated to explore the influence of columns on the flow state change,pressure distribution and wave energy transmission.Firstly,a numerical model is established based on the smoothed particle hydrodynamic method(SPH method).In the DualSPHysics program,the particle arrangement near the boundary is improved,which greatly increases the accuracy of multi-layer dynamic boundary conditions.Unique advantage in the liquid surface capture of particle method is fully utilized.At the same time,CUDA 10.0 parallel framework is established to equip with the GPU parallel computing module in numerical program,which greatly increases the computing efficiency.Subsequently,wave making verification of dam-break and regular wave is conducted to obtain the wavefront curves which meet the requirement of accuracy.Numerical simulations of dam-break wave impacting on the straight wall and regular wave impacting on horizontal plate are carried out respectively.Pressure data of physical experiment and numerical model are compared to verify the accuracy of numerical pressure extraction,both the horizontal and vertical direction.What's more,research of two-dimensional regular wave impact on the column-slab combined structure is carried out.Compared with the process of wave impacting on the horizontal plate,the influence of columns on the flow state is explored.Between the two structures,differences of the pressure duration curve and spatial distribution are clarified.The locations of dangerous points on the column-slab combined structure are determined.During the impact process,pressure duration curves on the front and rear columns are compared to discuss the vertical pressure distribution situations.By analyzing the velocity clouds and vector distributions,internal mechanism of two impact processes during one wave period is revealed.Finally,a three-dimensional model and numerical flume are built to study the impact process on the column-slab combined structure.Under the three-dimensional condition,velocity distributions on the bottom of the structure and liquid level-up situations are reflected intuitively.Besides,analyses of peak pressure statistics and impact forces are conducted.The results show that overall pressures on the back wave surface are larger than the front wave surface,local pressures all round are larger than the center part.