In this paper,numerical simulations on vortex-induced motions(VIM)of a semi-submersible at two different current headings are conducted over a wide range of current velocities.The simulations are performed with the co...In this paper,numerical simulations on vortex-induced motions(VIM)of a semi-submersible at two different current headings are conducted over a wide range of current velocities.The simulations are performed with the computational fluid dynamics(CFD)solver VIM-FOAM-SJTU which is an in-house solver developed based on the OpenFOAM framework.The turbulent flows are resolved with a shear stress transport-delayed detached eddy simulation(SST-DDES)model.Free decay tests for transverse and yaw motion are performed in calm still water to make sure the equivalent stiffness is setup correctly.Then the results of VIM,including motion response,forces and moments,and flow patterns are presented and analyzed carefully.Motions including transverse,in-line and yaw motion at different current headings and velocities are compared.Instantaneous vorticity in the wake regions at different time stamps are also illustrated for different current headings and velocities.展开更多
In this paper,numerical simulation is conducted via our in-house solver,vim-FOAM-SJTU,developed on open-source software,OpenFOAM.Flow around static rigid cylinders and elastically mounted rigid cylinder constrained to...In this paper,numerical simulation is conducted via our in-house solver,vim-FOAM-SJTU,developed on open-source software,OpenFOAM.Flow around static rigid cylinders and elastically mounted rigid cylinder constrained to free stream with free end are numerically investigated.Some significant conclusions are made by analyzing the different results between cases with and without free end.The turbulence model is implemented with a shear stress transport-based(SST-based)improved delayed detached eddy simulation(IDDES)approach in the vim-FOAM-SJTU.Firstly,The paper starts with the application of the vim-FOAM-SJTU solver to flow past fixed cylinder with free end at Reynolds number 43000.The numerical results are compared with experimental data.Comparison are satisfactory which implies the validity and accuracy of the current computational fluid dynamics(CFD)solver.The flow visualization in the vicinity of free-end is discussed.Subsequently,the solver is utilized to simulate the free end effect associated with the VIM of a cylinder submerged in current.The motion responses under different inflow velocities are studied.The relationship between transverse motion frequency,in-line motion frequency is discussed.Lastly,the effect of the free end on the vortex of the wake field is analyzed by comparing the 3-D vorticity diagrams of the free end cylinder.The responses of circular cylinder with or without free end are compared.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51909160,52131102 and 51879159)the National Key Research and Development Program of China(Grant No.2019YFB1704200).
文摘In this paper,numerical simulations on vortex-induced motions(VIM)of a semi-submersible at two different current headings are conducted over a wide range of current velocities.The simulations are performed with the computational fluid dynamics(CFD)solver VIM-FOAM-SJTU which is an in-house solver developed based on the OpenFOAM framework.The turbulent flows are resolved with a shear stress transport-delayed detached eddy simulation(SST-DDES)model.Free decay tests for transverse and yaw motion are performed in calm still water to make sure the equivalent stiffness is setup correctly.Then the results of VIM,including motion response,forces and moments,and flow patterns are presented and analyzed carefully.Motions including transverse,in-line and yaw motion at different current headings and velocities are compared.Instantaneous vorticity in the wake regions at different time stamps are also illustrated for different current headings and velocities.
基金supported by the National Natural Science Foundation of China(Grant Nos.52131102,51909160 and 51879159)the National Key Research and Development Program of China(Grant No.2019YFB1704200).
文摘In this paper,numerical simulation is conducted via our in-house solver,vim-FOAM-SJTU,developed on open-source software,OpenFOAM.Flow around static rigid cylinders and elastically mounted rigid cylinder constrained to free stream with free end are numerically investigated.Some significant conclusions are made by analyzing the different results between cases with and without free end.The turbulence model is implemented with a shear stress transport-based(SST-based)improved delayed detached eddy simulation(IDDES)approach in the vim-FOAM-SJTU.Firstly,The paper starts with the application of the vim-FOAM-SJTU solver to flow past fixed cylinder with free end at Reynolds number 43000.The numerical results are compared with experimental data.Comparison are satisfactory which implies the validity and accuracy of the current computational fluid dynamics(CFD)solver.The flow visualization in the vicinity of free-end is discussed.Subsequently,the solver is utilized to simulate the free end effect associated with the VIM of a cylinder submerged in current.The motion responses under different inflow velocities are studied.The relationship between transverse motion frequency,in-line motion frequency is discussed.Lastly,the effect of the free end on the vortex of the wake field is analyzed by comparing the 3-D vorticity diagrams of the free end cylinder.The responses of circular cylinder with or without free end are compared.
