A flow-intrinsic trigger for capturing reconfigurations in buoyancy-driven flows in automated PIV. (1st March 2019)

• Record Type: Journal Article
• Authors: Mommert, Michael; Schiepel, Daniel; Schmeling, Daniel; Wagner, Claus
• Is Part Of: Measurement science & technology. Volume 30:Number 4(2019:Apr.)
• Publication Date: 2019-03-01
• Subjects: conditional trigger -- PIV -- rare events -- automated measurement -- buoyancy-driven flows; Physical measurements -- Periodicals; Scientific apparatus and instruments -- Periodicals; Equipment and Supplies -- Periodicals; Science -- instrumentation -- Periodicals; Technology -- instrumentation -- Periodicals; Mesures physiques -- Périodiques; Physical measurements; Scientific apparatus and instruments; Periodicals; 502.87
• DOI: 10.1088/1361-6501/ab0619
• Languages: English
• ISSNs: 0957-0233

Abstract

Abstract: In order to acquire flow fields of rare reconfiguration events in buoyancy-driven flows, an automated flow-intrinsic trigger method for 3D particle image velocimetry (PIV) was developed. The trigger condition for initiating PIV is based on continuous multi-probe temperature measurements. The autonomously started PIV was realized with LED illumination and a controlled helium-filled soap bubble generator. The measured velocity fields reveal the transition between two different flow states in a mixed convection sample as proof of concept for this method. It is further proposed to consider the time series of all temperature probes for the trigger condition using proper orthogonal decomposition (POD). It is demonstrated that the use of this POD-based trigger condition allows one to detect flow events much earlier than the trigger based on single raw temperature signals.