Empirical correlations in B-C transition model were calibrated with experimental values of zero pressure gradient plates. Calibrated B-C transition model predicts reasonably transition positions with low inlet turbulence intensity. However, due to limitations of RANS method, B-C transition model’s accuracy diminishes for massively separated flows. A turbulence closure named transitional Delayed Detached-Eddy Simulation (BC-DDES) method is proposed which combines traditional SA-DDES method and B-C transition model. This method has the potential for accurately capturing massively separated boundary layers in transitional Reynolds number range. Numerical simulation of three-dimensional S-K flat plate shows that BC-DDES method obtains transition prediction consistent with baseline transition model. Comparisons are evaluated on circular cylinder in crossflow. It shows that pressure distribution and drag coefficient of cylinder calculated with BC-DDES method agree well with experimental data, with less computational costs than tHRLES method.

A constrained boundary recovery algorithm for 3D unstructured meshes which combines vector boundary advancing triangulation method(VBATM) with Steiner point perturbation is presented.From conforming mesh,constrained edges and faces could be recovered by Steiner point perturbation and VBATM to reconstruct triangulation on constrained faces.The tetrahedral-eating method can be used to get rid of Steiner points as many as possible.Different from existing methods,the algorithm does not need edges/faces swapping(flip) method and side compress method.Convergence and stability of the method are theoretically studied.Numerical examples are provided to illustrate effectiveness of the method.

Based on traditional flux method,a source six flux(SSF) model in cylindrical coordinate is proposed for arbitrary directional radiative intensity.Basic theory and numerical procedure of SSF model are presented in detail.Compared with directional radiative intensity by two flux method(TFM) and Backward Monte Carlo(BMC) method in cylindrical media,results of SSF method agree well with those of BMC.However,SSF method is more efficient than BMC,thus SSF method is more suitable in solving directional radiative intensity problems.

Two constrained Delaunay triangulation methods based on local reconstruction and side-swapping method are presented.Their convergence are shown.Appointed fields are renewed by boundary indicating method.It updates field scales by analysis of boundary curvature,axial and mutual smooth gradient of the domain.Based on Spring method,boundary points according to field scales are generated.By sign-area function and probability filer,initial points of field are obtained.Structure of meshes is optimized by Spring-Laplace method,side-swapping and side-collapse methods.The methods can be adaptive refined and made sparse successfully.They can be used to moving mesh and surface mesh generation of reflection surface.

Fourier trigonometric series algorithm used in Fick's diffusion law is extended to Fourier-Bessel algorithm in a fractal diffusion model for porous materials. It is applied to chemical engineering for computation of concentration distribution and relative adsorption. The fractal diffusion model introduces structure parameters d_f and θ Concentration distribution and relative adsorption calculated by fractal diffusion model are qualitatively consistent with those by Fick's diffusion law. d_f and θ exhibit different effects on concentration distribution of porous materials, and describe diffusion in porous materials well.

We present a method, vector boundary advancing method, to generate unstructured triangle meshes, and prove its feasibility. It lays out boundary points based on domain scales and generates background meshes with vector boundary advancing method. With sign-area function and probability filer, it obtains initial points in the domain. Spring-Laplace method and side-swapping method adjust location and structure of the mesh and prevent points from getting out of the domain. The method can do adaptive refine and derefine successfully and can deal with fixed-points, fixed-lines and inner-boundary. An efficient smooth adaptive triangulation divided in two-dimensional domain according to scales is realized.

The method of orthogonal collocation in Euclid's space has been extended to fractal space,with which the numerical computation of reaction-diffusion problem in chemical engineering has been also performed.The comparisons between calculated results and related analytical solutions show that this extended method gives the same results as theoretical ones,and permits to be used as a powerful numerical tool for the detailed analysis of chemical processes with fractal structure.