Research Of Lattice Boltzmann Method And Applications On Native Sunway Supercomputer

In recent years,more and more heterogeneous,many-core processors have been adopted in the Global TOP500 supercomputers.Supercomputer research in China has already ranked among the top in the world.Among them,China's Native supercomputer "Sunway Taihu Light" has ranked the first position in the global TOP500 ranking for 10 consecutive times from June 2013 to November2017.As the competition in the field of high-performance computing becomes serious algorithms,programs and application software based on high-performance computing platforms are receiving more and more attention.Lattice Boltzmann method(Lattice Boltzmann Method,LBM)is a very important numerical simulation method in computational fluid dynamics.The collision migration idea of LBM elementary particles and the use of Cartesian mesh division enable simple treatment of boundary condition and natural parallelism,which is suitable for large-scale numerical computation on the supercomputers.Based on the LBM of single-mesh and the parallel computing program developed on the “Sunway Blue Light” supercomputer of the National Supercomputer Center in Jinan,the master thesis implements the parallel computing and optimization of the program on the “Sunway Taihu Light”platform of the National Supercomputer Center in Wuxi.It is proposed to use double buffering and register communication mode to hide the communication time.And when calculating on the computing processing elements(CPEs),the management processing element(MPE)is responsible for adjusting the discrete data storage,speeding up the access to the main memory from CPEs,and further reducing the communication time and making parallel efficiency higher.On the basis of the verification of parallel efficiency,the NACA0012 standard model was selected as the computation model to calculate the flow conditions under a series of different angles of attack,and the change of the lift coefficient with the angle of attack and the average pressure of the airfoil surface at the 8 degree angle of attack were calculated.The pressure coefficient distribution and the calculation results are in agreement with the literature results.Aiming at the problem of large number of redundant grids when calculating the complex boundary model with single-mesh LBM and limited multi-mesh LBM to single node in the past,a cross-node multi-mesh LBM was proposed,implemented and optimized on the "Sunway Taihu Light" computing platform.According to the generation rules of multi-mesh and the uneven distribution of mesh,the MPI task division is adjusted appropriately to achieve the relative load balance,which effectively reduces the overall computing time.In terms of the application of LBM,based on the multi-mesh LBM and the "Sunway Taihu Light" computing platform,the serial double-cylinder and30P30 N airfoil are selected for computation.The surface pressure coefficients of the double-cylinder and 30P30 N airfoil are analyzed,which are basically consistent with the results in the literature.The results indicate that the multi-mesh LBM can accurately simulate complex flows.In addition,a complete model of an aircraft was selected for computational experiment.Coincident simulation results were obtained,which laid a good foundation for aerodynamic calculation of aircraft by using the application program and software with completely independent intellectual property rights.