Simultaneous Velocity and Density Gradient Measurements using Two-Point Focused Laser Differential Interferometry

Ceruzzi, Andrew; Cadou, Christopher P.

doi:10.2514/6.2019-2295

Cited by 34 publications

(7 citation statements)

References 16 publications

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“…In that same work measurements with ±0.9% uncertainty were reported when using channels from separate lines, the difference being only how the spacing between the FLDI probes was determined. A similar occurrence is also seen in Ceruzzi and Cadou (2019) with the turbulent jet measurements, in which the separation between probes in the D-FLDI was given with ±6% and the velocity measurements presented large error bars.…”

Section: Introductionsupporting

confidence: 83%

“…x 1 by analyzing the FLDI response to a weak lens crossing its path along the axis of beam separation. The method was later extended to also obtain x 2 in Ceruzzi and Cadou (2019).…”

Section: Indirect Estimation Of Fldi Parametersmentioning

confidence: 99%

“…Duplication of the basic FLDI into two or more closely spaced systems can be achieved in many different ways (Ceruzzi and Cadou 2019;Jewell et al 2019;Bathel et al 2020;Weisberger et al 2020;Gragston et al 2021a). In the present work, the D-FLDI is produced by means of a Wollaston prism of 2 • splitting angle together with a polarizer, highlighted in red in Fig.…”

Section: Double-foci Fldimentioning

confidence: 99%

“…Results followed the jet nominal values, albeit with a consistent offset. Ceruzzi and Cadou (2019) also performed velocity measurements of a turbulent free jet of air. Results agreed to hot-wire measurements and a velocity decay model if a certain distance from the jet exit was observed, although large uncertainties were reported.…”

Section: Introductionmentioning

confidence: 99%

“…Three methods are currently established in the literature to obtain the separation distance between FLDI systems: directly imaging the beams with a beam profiler; gradually blocking the beams with a precision-controlled stopper (Weisberger et al 2020); or analyzing the system response to a lens with large focal length crossing the path of the beams (Ceruzzi and Cadou 2019).…”

Section: Introductionmentioning

confidence: 99%

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A low-effort and inexpensive methodology to determine beam separation distance of multi-foci FLDI

Camillo

Wagner

2022

Exp Fluids

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A new method is presented to measure the separation distance between probing volumes of closely spaced multi-foci Focused Laser Differential Interferometers (FLDI). The accuracy and precision of this distance measurement directly translate into the quality of convection velocity measurements performed by means of arrays of FLDI. The suggested method is based on the detection of a propagating weak blast wave, generated with a simple and inexpensive apparatus using an automotive spark plug. Demonstration is conducted using an FLDI with two foci (D-FLDI). The generated blast wave is probed at multiple distances from its source to verify its weakening into an acoustic pulse, which offers ideal conditions to the proposed methodology. D-FLDI separation distance measurement using the new approach is compared to measurements using beam profiler images and to the alternative currently established in the literature, based on the FLDI response to a moving weak lens. Tests are made on varying internal configurations of the D-FLDI, while the distance between the two systems is kept constant. Results show the present method to have improved accuracy and robustness in comparison with the moving lens approach, while requiring significantly less effort. Measured separation distances obtained from blast wave detections in a single location are within $$0.5 \%$$ 0.5 % of the reference value measured through the beam profiler. This procedure is therefore a practical and reliable alternative to the measurement using beam profiler imaging, with similar quality. Its advantages concern associated costs, flexibility when measuring in constrained spaces such as in proximity to walls, and applicability to systems in which beam imaging is not an option, such as multi-point line FLDI.

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Section: Introductionsupporting

confidence: 83%

“…x 1 by analyzing the FLDI response to a weak lens crossing its path along the axis of beam separation. The method was later extended to also obtain x 2 in Ceruzzi and Cadou (2019).…”

Section: Indirect Estimation Of Fldi Parametersmentioning

confidence: 99%