Analyzing a Turbulent Jet Flow using Proper Orthogonal Decomposition

Proper orthogonal decomposition (POD) is used in fluid dynamics in order to breakdown a variable into spatial and time coefficients. In the context of this poster, snapshot POD has been used to decompose both the streamwise and crosstream velocity planes as gathered from particle image velocimetry (PIV) preformed on a multi-aperture single expansion ramp nozzle (MARS). From this POD analysis, the most energetic modes can be identified, and coherent structures in the various mode shapes can be used to help with sensor placement. Furthermore, the instantaneous velocity field can be reconstructed using a variable number of POD modes. The more modes that are used, the more accurate the reconstruction will be, however, it was observed that using less than one third of the POD modes to reconstruct the instantaneous velocity field can accurately capture coherent structures while reducing the order of complexity of the flow field. This method of reconstruction shows promise in reducing the computational intensity of large data sets from non-time-resolved particle image velocimetry to a simpler datasets.