The effects of adverse pressure gradient(APG)on Reynolds stresses in turbulent boundary layers(TBLs)with APG were analyzed.The difficulty of this work was attributable to the Reynolds stresses in TBLs with APG under t...The effects of adverse pressure gradient(APG)on Reynolds stresses in turbulent boundary layers(TBLs)with APG were analyzed.The difficulty of this work was attributable to the Reynolds stresses in TBLs with APG under two combined effects,i.e.:effect of upstream flow and effect of APG.The effect of upstream flow is an inherent effect no matter pressure gradient exists or not.The individual effect was analyzed from absolute developments of Reynolds stresses in TBLs with zero pressure gradient(ZPG)firstly.Effect of APG was then analyzed from absolute developments of Reynolds stresses in TBLs with APG.Result showed that,for absolute development of mean streamwise Reynolds stresses,APG accelerated its development in TBL with ZPG;for absolute development of mean normal or shear Reynolds stresses,APG increased their magnitude in the outer part,and decreased their extent of large value region.展开更多
A new form of universal wall function is proposed in this work,which can be applied to a variety of eddy viscosity models including one-equation models and two-equation models.The new wall function approximates the an...A new form of universal wall function is proposed in this work,which can be applied to a variety of eddy viscosity models including one-equation models and two-equation models.The new wall function approximates the analytical results of the Spalart-Allmaras turbulence model in the near wall region of the zero pressure gradient incompressible turbulent boundary layer.This approximate form can be applied as a unified eddy-viscosity-based wall function and a concise unified wall function of velocity distribution is proposed after integration.On this basis,the grid Reynolds number is introduced and a function for judging the position of the first layer grid is given.The new wall function is validated using the NACA0012 and the axisymmetric separated boundary layer.It is proved that the wall function is accurate and universal,and the grid requirements are lower in applications.展开更多
基金Natural Science Foundation of Shanghai(15ZR1422500)Initiative Projects of Shanghai Jiao Tong University Young Teachers(AF4130024)
文摘The effects of adverse pressure gradient(APG)on Reynolds stresses in turbulent boundary layers(TBLs)with APG were analyzed.The difficulty of this work was attributable to the Reynolds stresses in TBLs with APG under two combined effects,i.e.:effect of upstream flow and effect of APG.The effect of upstream flow is an inherent effect no matter pressure gradient exists or not.The individual effect was analyzed from absolute developments of Reynolds stresses in TBLs with zero pressure gradient(ZPG)firstly.Effect of APG was then analyzed from absolute developments of Reynolds stresses in TBLs with APG.Result showed that,for absolute development of mean streamwise Reynolds stresses,APG accelerated its development in TBL with ZPG;for absolute development of mean normal or shear Reynolds stresses,APG increased their magnitude in the outer part,and decreased their extent of large value region.
基金supported by the National Numerical Wind Tunnel Project(No.NNW2019ZT1-A03)the National Natural Science Foundation of China(No.11721202).
文摘A new form of universal wall function is proposed in this work,which can be applied to a variety of eddy viscosity models including one-equation models and two-equation models.The new wall function approximates the analytical results of the Spalart-Allmaras turbulence model in the near wall region of the zero pressure gradient incompressible turbulent boundary layer.This approximate form can be applied as a unified eddy-viscosity-based wall function and a concise unified wall function of velocity distribution is proposed after integration.On this basis,the grid Reynolds number is introduced and a function for judging the position of the first layer grid is given.The new wall function is validated using the NACA0012 and the axisymmetric separated boundary layer.It is proved that the wall function is accurate and universal,and the grid requirements are lower in applications.
