Conference:
22nd International Symposium on Application of Laser and Imaging Techniques to Fluid Mechanics • LISBON | PORTUGAL • JUNE 29-JULY 2, 2026
Title:
On the Memory of Measurements in Spray Diagnostics
Authors:
M.R.O. Panão (1), P. Rehberg (2,3) and W. Schäfer (2,4)
1. ADAI, University of Coimbra, Portugal
2. AOM-Systems GmbH
3. TU-Darmstadt
4. ai-quanton GmbH
Abstract: In spray characterization, a measurement takes time to retrieve sufficient information to reach an adequate sample size on which statistical methods are applied. What if the spray changes during the measurement? In practice, the spray droplets may change their size and dynamics, which is analogous to establishing new “memories” of their characteristics. In the context of measurement, “memory” refers to the present signal carrying traces of the recent past, including flow, particles, light–matter interaction, and instruments. This past imprint turns raw observations into a time‑dependent record rather than isolated snapshots. This study investigates how to quantify memory in measurements made by the time-shifting technique applied to spray characterization using the infodynamic concept of mutual information between successive sample frames. The assessment of “how much of the past remains in the present” presents an identifiable pattern that we can attribute to long-term measurement memories or ongoing measurement memory formation. By adding a new spray characterization layer based on the informational macrostate of the local spray, we provide non-deterministic quantifiable data that are useful for the development and validation of numerical models.