The turbulent wakes behind trailing edge are analyzed for understanding of the flow mechanisms responsible for the generation of trailing edge noise. The TILS （turbulence integral length scale） of the turbulent wake...The turbulent wakes behind trailing edge are analyzed for understanding of the flow mechanisms responsible for the generation of trailing edge noise. The TILS （turbulence integral length scale） of the turbulent wake of hydrofoil with blunt trailing edge is calculated from TR-PIV （time-resolved particle image velocimetry） data. The temporal auto-correlation method based on Taylor hypothesis and spatial correlation method are used to get the TILS information of the turbulent wake of hydrofoil, respectively The comparison of results by two methods indicates that the spatial correlation method is independent on Taylor hypothesis and suitable to strong turbulence and non-isotropic turbulence.展开更多
It is known that free-surface flows with small slopes can be described by classical lubrication theory.By replacing the assumption of quasi-parallel flows with local wedge flows,the classical lubrication theory has be...It is known that free-surface flows with small slopes can be described by classical lubrication theory.By replacing the assumption of quasi-parallel flows with local wedge flows,the classical lubrication theory has been generalized to the situation with finite surface slopes and vanishing fluxes,e.g.,steady capillary flows with moving contact lines.In this work,this theory is further extended by imposing the contribution of finite fluxes,which can be modeled by a source/sink flow in a wedge.The resulting lubrication equation is used to investigate the surface morphologies observed in dip coating of an inclined plate,including the Landau-Levich-Derjaguin film,dimple and capillary shock.Dependence of these structures on the inclination angle and relative speed with respect to the plate is discussed in detail.Numerical solutions of the lubrication equation agree well with available asymptotic theory.展开更多
文摘The turbulent wakes behind trailing edge are analyzed for understanding of the flow mechanisms responsible for the generation of trailing edge noise. The TILS （turbulence integral length scale） of the turbulent wake of hydrofoil with blunt trailing edge is calculated from TR-PIV （time-resolved particle image velocimetry） data. The temporal auto-correlation method based on Taylor hypothesis and spatial correlation method are used to get the TILS information of the turbulent wake of hydrofoil, respectively The comparison of results by two methods indicates that the spatial correlation method is independent on Taylor hypothesis and suitable to strong turbulence and non-isotropic turbulence.
基金the National Natural Science Foundation of China(Grant Nos.11972340,11932019,and 11621202).
文摘It is known that free-surface flows with small slopes can be described by classical lubrication theory.By replacing the assumption of quasi-parallel flows with local wedge flows,the classical lubrication theory has been generalized to the situation with finite surface slopes and vanishing fluxes,e.g.,steady capillary flows with moving contact lines.In this work,this theory is further extended by imposing the contribution of finite fluxes,which can be modeled by a source/sink flow in a wedge.The resulting lubrication equation is used to investigate the surface morphologies observed in dip coating of an inclined plate,including the Landau-Levich-Derjaguin film,dimple and capillary shock.Dependence of these structures on the inclination angle and relative speed with respect to the plate is discussed in detail.Numerical solutions of the lubrication equation agree well with available asymptotic theory.
