Detailed analysis of POD method applied on turbulent flow

Radka Kellnerova¹, Libor Kukacka¹, Vaclav Uruba², Klara Jurcakova² and Zbynek Janour²

¹ Institute of Thermomechanics, Department of Meteorology and Environment Protection, Charles University,
radka.kellnerova@it.cas.cz ; kukacka@it.cas.cz
² Institute of Thermomechanics
uruba@it.cas.cz ; jurcakova@it.cas.cz ; janour@it.cas.cz

Published online: 16 April 2012

Abstract

Proper orthogonal decomposition (POD) of a very turbulent flow inside a street canyon is performed. The energy contribution of each mode is obtained. Also, physical meaning of the POD result is clarified. Particular modes of POD are assigned to the particular flow events like a sweep event, a vortex behind a roof or a vortex at the bottom of a street. Test of POD sensitivity to the acquisition time of data records is done. Test with decreasing sample frequency is also executed. Further, interpolation of POD expansion coefficient is performed in order to test possible increase in sample frequency and get new information about the flow from the POD analysis. We tested a linear and a spline type of the interpolation and the linear one carried out a slightly better result.