Global stability analysis of axisymmetric boundary layers

Abstract

Global stability analysis of axisymmetric boundary layers RAMESHKUMAR BHORANIYA, VINOD NARAYANAN, Mechanical Engineer- ing, Indian Institute of Technology, Gandhinagar, India — Global stability analysis of the axisymmetric boundary layer flow explores the stability features of a nonpar- allel flow. Consider an incompressible flow past a cylinder, where flow direction is parallel to the axis of cylinder. The ensuing boundary layer is axisymmetric but non-similar. Due to the boundary layer growth, the velocity profile is two dimen- sional. This work aims to understand the nonparallel effects of an axisymmetric boundary layer using a biglobal stability analysis. The linearized biglobal stability equations are derived in polar cylindrical coordinates. The resulting stability equa- tions along with boundary conditions form an eigenvalue problem, which is solved using Chebyshev spectral collocation method. Arnoldi’s algorithm is used to com- pute selective eigenvalues and eigenfunctions. The results show that the nonparallel effects are considerable at very moderate Reynolds numbers. More detailed results will be presented at the time of conference