| Turbulent gas-solid two-phase flow is a complex multi-scale problem.In order to capture the influence of small-scale vortex structure on particles in the flow field,the use of high-resolution uniform grid in numerical simulation will bring huge computational load.In this paper,the turbulent particle-laden round jet is taken as the research object.From the two aspects of grid adaptive simulation algorithm based on wavelet filtering and distributed parallel calculation of particle-laden round jet.The efficient numerical simulation algorithm of gas-solid two-phase jet is studied.Firstly,the adaptive mesh(AMR)algorithm based on wavelet filtering is constructed by using the multi-resolution analysis and fast transformation characteristics of the second generation wavelet.The wavelet coefficients associated with the vortex structure and the mesh are obtained by the three-dimensional wavelet transform of the vorticity field.Then the adaptive adjustment of the mesh is realized by filtering the wavelet coefficients.On this basis,the three-dimensional single-phase round jet direct numerical simulation is carried out,the simulation results are consistent with the corresponding experimental results,which verifies the accuracy of the adaptive algorithm in this paper.In addition,the calculation time and data storage are compared,and the results show that AMR algorithm based on wavelet is better than uniform grid,which can save two orders of magnitude and two levels of calculation storage and time.Then,under the AMR framework,a parallel algorithm of gas-solid two-phase flow simulation based on the Eulerian-Lagrangian method is developed.The distributed storage and calculation of the flow field are realized by the way of decomposition and parallel of the calculation domain.The calculation domain is divided based on the method of space filling curve to balance the load.The dynamic division of the calculation domain in the adaptive process of the flow field grid is realized by setting the load imbalance factor.The mapping between particles and flow field blocks is established during the adaptive process of the grid when crossing the boundary.To achieve particle messaging between parallel computing processes.Finally,a parallel computing framework of AMR gas-solid two-phase flow based on wavelet is given.The parallel test shows that the particle parallel algorithm can maintain linear parallel acceleration within 256 cores under the O(10~7)particle number.Finally,on the basis of AMR parallel computing program framework,the large eddy simulation of three-dimensional turbulent particle-laden round jet under AMR is realized.The diffusion characteristics of particles in circular turbulent jet under different Stokes number conditions are mainly discussed,and the particle distribution laws consistent with those observed in previous experiments are captured,and the calculation time and grid compression are carried out.The analysis of rate shows the feasibility of the wavelet AMR and particle parallel algorithm to simulate turbulent particle-laden round jet efficiently. |
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