A numerical investigation on the effectiveness of the actuator disc method in producing the interactions of multiple tidal stream devices via the 3D-RANS finite element model Telemac3D is explored. The methodology for...A numerical investigation on the effectiveness of the actuator disc method in producing the interactions of multiple tidal stream devices via the 3D-RANS finite element model Telemac3D is explored. The methodology for the implementation of the source term to represent an array of 20 m rotor diameter turbines deployed in an idealized channel is reviewed and discussed in detail. Flow interactions between multiple turbines are investigated for a single row arrangement with only two turbines and a two row arrangement containing three turbines. The results demonstrate that the non-hydrostatic solver shows better agreement when validated against published experimental data. Notably,the mesh density at the device location can strongly influence the simulated thrust from the disc. Although the actuator disc model can generally replicate the wake interactions well, the results indicate that it cannot accurately characterize the flow for regions with high turbulences. While a model setup with the largest lateral spacing(1.5D) demonstrates excellent agreement with the experimental data, the 0.5D model(smallest gap) deviates by up to 25%. These findings demonstrate the effectiveness of the applied source term in reproducing the wake profile, which is comparable with the published data, and highlight the inherent nature of the RANS and actuator disc models.展开更多
Usually simulations on environment flood issues will face the scalability problem of large scale parallel computing.The plain parallel technique based on pure MPI is difficult to have a good scalability due to the lar...Usually simulations on environment flood issues will face the scalability problem of large scale parallel computing.The plain parallel technique based on pure MPI is difficult to have a good scalability due to the large number of domain partitioning.Therefore,the hybrid programming using MPI and OpenMP is introduced to deal with the issue of scalability.This kind of parallel technique can give a full play to the strengths of MPI and OpenMP.During the parallel computing,OpenMP is employed by its efficient fine grain parallel computing and MPI is used to perform the coarse grain parallel domain partitioning for data communications.Through the tests,the hybrid MPI/OpenMP parallel programming was used to renovate the finite element solvers in the BIEF library of Telemac.It was found that the hybrid programming is able to provide helps for Telemac to deal with the scalability issue.展开更多
文摘A numerical investigation on the effectiveness of the actuator disc method in producing the interactions of multiple tidal stream devices via the 3D-RANS finite element model Telemac3D is explored. The methodology for the implementation of the source term to represent an array of 20 m rotor diameter turbines deployed in an idealized channel is reviewed and discussed in detail. Flow interactions between multiple turbines are investigated for a single row arrangement with only two turbines and a two row arrangement containing three turbines. The results demonstrate that the non-hydrostatic solver shows better agreement when validated against published experimental data. Notably,the mesh density at the device location can strongly influence the simulated thrust from the disc. Although the actuator disc model can generally replicate the wake interactions well, the results indicate that it cannot accurately characterize the flow for regions with high turbulences. While a model setup with the largest lateral spacing(1.5D) demonstrates excellent agreement with the experimental data, the 0.5D model(smallest gap) deviates by up to 25%. These findings demonstrate the effectiveness of the applied source term in reproducing the wake profile, which is comparable with the published data, and highlight the inherent nature of the RANS and actuator disc models.
文摘Usually simulations on environment flood issues will face the scalability problem of large scale parallel computing.The plain parallel technique based on pure MPI is difficult to have a good scalability due to the large number of domain partitioning.Therefore,the hybrid programming using MPI and OpenMP is introduced to deal with the issue of scalability.This kind of parallel technique can give a full play to the strengths of MPI and OpenMP.During the parallel computing,OpenMP is employed by its efficient fine grain parallel computing and MPI is used to perform the coarse grain parallel domain partitioning for data communications.Through the tests,the hybrid MPI/OpenMP parallel programming was used to renovate the finite element solvers in the BIEF library of Telemac.It was found that the hybrid programming is able to provide helps for Telemac to deal with the scalability issue.
