Different advection schemes and two-equation turbulence closure models based on eddy viscosity concept are used to compute the drag coefficient around a circular cylinder at high Reynolds number (106).The numerical re...Different advection schemes and two-equation turbulence closure models based on eddy viscosity concept are used to compute the drag coefficient around a circular cylinder at high Reynolds number (106).The numerical results from these simulations are compared with each other and with experimental data in order to evaluate the performance of different combinations of advection scheme and two-equation turbulence model.The separate contributions from form drag and friction drag are also ana-lyzed.The computational results show that the widely used standard k-ε turbulence closure is not suitable for such kind of study,while the other two-equation turbulence closure models produce acceptable results.The influence of the different advection schemes on the final results are small compared to that produced by the choice of turbulence closure method. The present study serves as a reference for the choice of advection schemes and turbulence closure models for more complex numerical simulation of the flow around a circular cylinder at high Reynolds number.展开更多
A concept of entropy increment ratio()is introduced for compressible turbulence simulation through a series of direct numerical simulations(DNS). represents the dissipation rate per unit mechanical energy with the...A concept of entropy increment ratio()is introduced for compressible turbulence simulation through a series of direct numerical simulations(DNS). represents the dissipation rate per unit mechanical energy with the benefit of independence of freestream Mach numbers.Based on this feature,we construct the shielding function fs to describe the boundary layer region and propose an entropy-based detached-eddy simulation method(SDES).This approach follows the spirit of delayed detached-eddy simulation(DDES)proposed by Spalart et al.in 2005,but it exhibits much better behavior after their performances are compared in the following flows,namely,pure attached flow with thick boundary layer(a supersonic flat-plate flow with high Reynolds number),fully separated flow(the supersonic base flow),and separated-reattached flow(the supersonic cavity-ramp flow).The Reynolds-averaged Navier-Stokes(RANS)resolved region is reliably preserved and the modeled stress depletion(MSD)phenomenon which is inherent in DES and DDES is partly alleviated.Moreover,this new hybrid strategy is simple and general,making it applicable to other models related to the boundary layer predictions.展开更多
基金the support by the National Basic Research Program of China(Nos.2009CB421201,2011CB403501)the National Natural Science Foundation of China(Nos.40876012,41076007)
文摘Different advection schemes and two-equation turbulence closure models based on eddy viscosity concept are used to compute the drag coefficient around a circular cylinder at high Reynolds number (106).The numerical results from these simulations are compared with each other and with experimental data in order to evaluate the performance of different combinations of advection scheme and two-equation turbulence model.The separate contributions from form drag and friction drag are also ana-lyzed.The computational results show that the widely used standard k-ε turbulence closure is not suitable for such kind of study,while the other two-equation turbulence closure models produce acceptable results.The influence of the different advection schemes on the final results are small compared to that produced by the choice of turbulence closure method. The present study serves as a reference for the choice of advection schemes and turbulence closure models for more complex numerical simulation of the flow around a circular cylinder at high Reynolds number.
基金supported by the National Basic Research Program of China(Grant No.2009CB724104)the Innovation Foundation of BUAA for PhD Graduates and the Academic New Artist Award of BUAA for PhD Graduates
文摘A concept of entropy increment ratio()is introduced for compressible turbulence simulation through a series of direct numerical simulations(DNS). represents the dissipation rate per unit mechanical energy with the benefit of independence of freestream Mach numbers.Based on this feature,we construct the shielding function fs to describe the boundary layer region and propose an entropy-based detached-eddy simulation method(SDES).This approach follows the spirit of delayed detached-eddy simulation(DDES)proposed by Spalart et al.in 2005,but it exhibits much better behavior after their performances are compared in the following flows,namely,pure attached flow with thick boundary layer(a supersonic flat-plate flow with high Reynolds number),fully separated flow(the supersonic base flow),and separated-reattached flow(the supersonic cavity-ramp flow).The Reynolds-averaged Navier-Stokes(RANS)resolved region is reliably preserved and the modeled stress depletion(MSD)phenomenon which is inherent in DES and DDES is partly alleviated.Moreover,this new hybrid strategy is simple and general,making it applicable to other models related to the boundary layer predictions.
