Instantaneous one-dimensional velocity measurements of gas flow field under low-pressure conditions based on femtosecond laser-extended electrode discharge
Year: 2026
Type: article
Abstract: Accurate measurement of gas flow field velocity is crucial for revealing the dynamic characteristics of fluid evolution. Although femtosecond laser electronic excitation tagging (FLEET) has become a vital tool for gas flow velocimetry due to its non-intrusive and tracer-free advantages, its applicability is significantly compromised under low-pressure conditions due to severe signal attenuation. Here, we establish a research platform for velocity measurement under low-pressure conditions based on femtosecond laser-extended electrode discharge. Experimental results demonstrate that the proposed technique enhances the signal intensity by over an order of magnitude compared to FLEET in low-pressure environments. This enables single-shot and one-dimensional (1D) velocity measurements at ultra-low pressures down to 1 kPa. Benefiting from the significantly improved signal-to-noise ratio, this technique overcomes the reliance on ICCD cameras, achieving flow field imaging using only a DSLR camera. Furthermore, we propose an adaptive centroid extraction algorithm based on light intensity moment features, which achieves sub-pixel positioning and realizes 1D transient velocity measurement. Quantitative velocity field measurements under varying flow rates, pressures, and spatial positions verify the accuracy and stability of the proposed technique for low-pressure flow field measurements. This study provides a low-cost, easily deployable, and highly reliable approach for the refined diagnosis of complex low-pressure flow fields.
Source: Optics Express
DOI: 10.1364/oe.613120
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,270
OpenAlex ID: W7224120007