Published 4 issues per year
ISSN Print: 1065-3090
ISSN Online: 1940-4336
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POD ANALYSIS OF A BLOOMING JET AT A MODERATE REYNOLDS NUMBER
ABSTRACT
Jet flow in general has a wide range of applications, from propulsion of large aircraft to cooling of electronic circuit. Jet is also a source of noise which is needed to be controlled suitably and since large scales of fluid motion play a primary role in transport phenomena, selective manipulation of these structures is needed to achieve efficient control. The snapshot method of proper orthogonal decomposition (POD) has been utilized to analyze the fluctuating velocity vector for a blooming jet at the Reynolds number Re = 4300 and excitation frequency ratio Rf = 2.4. The baseline data is developed with the help of large eddy simulation (LES). Higher-order spatial and temporal discretizations are used to solve the governing equations. For Re = 4300, at least 96 snapshots are required for good spectral resolution. For capturing 90% of the total energy of the unsteady flow field, at least 40 modes are required. The eigenvalue/singular distributions for the forced jet show the formation of odd-even pairs of modes. The first pair itself contains the details of branching. In addition, higher-order modes capture the inherent jet instability mechanisms and related flow structures.