Flow periodicity analysis past a flapping airfoil using proper orthogonal decomposition

Chandan Bose, Sunetra Sarkar

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract / Description of output

The transition in the flow-periodicity behind a pitching-plunging airfoil is explored by proper orthogonal decomposition (POD) analysis. The high fidelity simulation of the vortical flow past a flapping airfoil is carried out in a low Reynolds number regime (Re = 1000) by a finite volume based incompressible Navier-Stokes solver. The flow topology transitions from a periodic to chaotic dynamics as the non-dimensional plunge amplitude (h) is increased at a constant pitch amplitude and flapping frequency. POD is opted to decompose the flow field into a set of orthogonal modes of varying energy content using the numerically obtained flow snapshots. It is observed that 99.35% of the total kinetic energy is captured by the first 10 high energy POD modes in the periodic regime (h = 0:5). However, the number of POD modes required to reconstruct the flow-field accurately in- creases as the periodicity of flow is lost. It is seen that the first 10 POD modes capture only 51.19% of the total energy in the chaotic state (h = 1:25). Interesting insights into the change of flow periodicity are obtained by comparing the formation and symmetry of the dominant POD modes of different disparate dynamics with the increase in h. Moreover, the time histories and phase portraits of the corresponding temporal coefficients reflect the dynamical transition as well.

Original languageEnglish
Title of host publication47th AIAA Fluid Dynamics Conference, 2017
PublisherAmerican Institute of Aeronautics and Astronautics Inc. (AIAA)
ISBN (Print)9781624105005
Publication statusPublished - 2 Jun 2017
Event47th AIAA Fluid Dynamics Conference, 2017 - Denver, United States
Duration: 5 Jun 20179 Jun 2017

Publication series

Name47th AIAA Fluid Dynamics Conference, 2017


Conference47th AIAA Fluid Dynamics Conference, 2017
Country/TerritoryUnited States


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