Comparative assessment of pressure field reconstructions from particle image velocimetry measurements and Lagrangian particle tracking

Determination of mean pressure from PIV in compressible flows using the Reynolds-averaging approach

“…3 to 5). The flow configuration of the experiments is an axisymmetric base flow at Mach 0.7, similar to the one studied in Blinde et al (2015) and van Gent et al (2017a). The compressible base flow is characterised by largescale unsteady separation and a richness in terms of flow scales making it particularly suited to provide a realistic and challenging test case.…”

“…It is generally accepted that the accuracy with which the material acceleration is determined is the dominant factor for the pressure reconstruction (Violato et al 2011;de Kat and van Oudheusden 2012;van Gent et al 2017a), setting particular demands on both spatial and temporal resolution of the velocity measurement. For application in the high-speed regime, which is the area of interest of the present communication, meeting these demands becomes increasingly challenging, for a variety of reasons.…”

“…Although the feasibility of using a four-pulse procedure has been validated on the basis of synthetic experimental data (van Gent et al 2017a) and advances have been made by tracking individual tracer particles (Novara et al 2016), achieving the accuracy required for satisfactory instantaneous pressure results is challenging (Blinde et al 2015). Furthermore, setting up and operating a multi-pulse PIV system is significantly more complexity and laborious than using a standard double-pulse system.…”

“…Furthermore, since it is a statistical approach, it benefits from a reduction in uncertainty by combining a large ensemble of measurements. The merits of obtaining mean pressure fields from planar PIV measurements were recently demonstrated in van Gent et al (2017b) who applied the technique to assess the impact of nozzle length and the presence of an exhaust plume on transonic and supersonic base flows with exhaust plumes. The above shows the pursuit of the mean pressure data as a worthwhile and realistic objective for high-speed flow applications.…”

“…A justification of this approach has been provided by an assessment of a synthetic PIV experiment constructed on the basis of a numerical simulation (van Gent et al 2017a), which demonstrated that instantaneous pressure data could be reliably reconstructed under the assumptions mentioned above. However, as mentioned, the current interest is to obtain a reliable result for the mean pressure using velocity statistics in a Reynolds-averaging approach.…”