Three aluminium channel sections of US standard extruded dimension are mounted as cantilevers with x-axis symmetry. The flexural bending and shear that arise with applied axial torsion are each considered theoreticall...Three aluminium channel sections of US standard extruded dimension are mounted as cantilevers with x-axis symmetry. The flexural bending and shear that arise with applied axial torsion are each considered theoretically and numerically in terms of two longitudinal axes of loading not coincident with the shear centre. In particular, the warping displacements, stiffness and stress distributions are calculated for torsion applied to longitudinal axes passing through the section’s centroid and its web centre. The stress conversions derived from each action are superimposed to reveal a net sectional stress distribution. Therein, the influence of the axis position upon the net axial and shear stress distributions is established compared to previous results for each beam when loading is referred to a flexural axis through the shear centre. Within the net stress analysis is, it is shown how the constraint to free warping presented by the end fixing modifies the axial stress. The latter can be identified with the action of a ‘bimoment’ upon each thin-walled section.展开更多
This paper presents Reynolds stress constrained large eddy simulation(RSC-LES)method applied to a U-duct flow.Different from traditional Reynolds-averaged Navier-Stokes/detached eddy simulation(RANS/DES)hybrid method(...This paper presents Reynolds stress constrained large eddy simulation(RSC-LES)method applied to a U-duct flow.Different from traditional Reynolds-averaged Navier-Stokes/detached eddy simulation(RANS/DES)hybrid method(including DES method),the RSC-LES method solves the LES equations in the whole computation domain with the near-wall regions being constrained by a prescribed Reynolds stress.By doing so it is possible to overcome the log-law mismatch(LLM)problem in hybrid method.The RSC-LES results show better agreement with experiment result.Compared with RANS and DES,RSC-LES gives more accurate pressure coefficients and friction coefficients on the wall,because the RSC-LES method captures the separation point and reattachment point on the inner wall.The computation results show that the RSC-LES method has the potential to solve the log-law mismatch problem of RANS/DES hybrid method and predict complex phenomena of internal flow field.展开更多
文摘Three aluminium channel sections of US standard extruded dimension are mounted as cantilevers with x-axis symmetry. The flexural bending and shear that arise with applied axial torsion are each considered theoretically and numerically in terms of two longitudinal axes of loading not coincident with the shear centre. In particular, the warping displacements, stiffness and stress distributions are calculated for torsion applied to longitudinal axes passing through the section’s centroid and its web centre. The stress conversions derived from each action are superimposed to reveal a net sectional stress distribution. Therein, the influence of the axis position upon the net axial and shear stress distributions is established compared to previous results for each beam when loading is referred to a flexural axis through the shear centre. Within the net stress analysis is, it is shown how the constraint to free warping presented by the end fixing modifies the axial stress. The latter can be identified with the action of a ‘bimoment’ upon each thin-walled section.
文摘This paper presents Reynolds stress constrained large eddy simulation(RSC-LES)method applied to a U-duct flow.Different from traditional Reynolds-averaged Navier-Stokes/detached eddy simulation(RANS/DES)hybrid method(including DES method),the RSC-LES method solves the LES equations in the whole computation domain with the near-wall regions being constrained by a prescribed Reynolds stress.By doing so it is possible to overcome the log-law mismatch(LLM)problem in hybrid method.The RSC-LES results show better agreement with experiment result.Compared with RANS and DES,RSC-LES gives more accurate pressure coefficients and friction coefficients on the wall,because the RSC-LES method captures the separation point and reattachment point on the inner wall.The computation results show that the RSC-LES method has the potential to solve the log-law mismatch problem of RANS/DES hybrid method and predict complex phenomena of internal flow field.
