The physical mechanism for generation of streamwise vortices (or rib vortices) in the cylinder wake was numerically investigated with a finite-difference scheme. Rayleigh's theory of centrifugal instability for i...The physical mechanism for generation of streamwise vortices (or rib vortices) in the cylinder wake was numerically investigated with a finite-difference scheme. Rayleigh's theory of centrifugal instability for inviscid axisymmetric flow was extended to analyze the 2-D primary flows. Centrifugal instability occurs when Ray greater than 0. Stability analyses were carried out with this discriminant for primary flows at different time levels in a half shedding period of the von Karman (or vK) vortices. Unstable areas were identified and the locations of rib vortices were coincident well with the unstable areas within the first wavelength of vK vortices behind the cylinder. The numerical results also show that rib vortices experience amplification in this region. (Edited author abstract) 17 Refs.展开更多
基金The project supported by the National Natural Science Foundation of China
文摘The physical mechanism for generation of streamwise vortices (or rib vortices) in the cylinder wake was numerically investigated with a finite-difference scheme. Rayleigh's theory of centrifugal instability for inviscid axisymmetric flow was extended to analyze the 2-D primary flows. Centrifugal instability occurs when Ray greater than 0. Stability analyses were carried out with this discriminant for primary flows at different time levels in a half shedding period of the von Karman (or vK) vortices. Unstable areas were identified and the locations of rib vortices were coincident well with the unstable areas within the first wavelength of vK vortices behind the cylinder. The numerical results also show that rib vortices experience amplification in this region. (Edited author abstract) 17 Refs.
