DLR-Logo -> http://www.dlr.de
DLR Portal Home | Imprint | Privacy Policy | Contact | Deutsch
Fontsize: [-] Text [+]

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

Ponchio Camillo, Giannino and Wagner, Alexander (2022) A low-effort and inexpensive methodology to determine beam separation distance of multi-foci FLDI. Experiments in Fluids, 63 (53), pp. 1-13. Springer Nature. doi: 10.1007/s00348-022-03401-0. ISSN 0723-4864.

[img] PDF - Published version

Official URL: https://link.springer.com/article/10.1007/s00348-022-03401-0?utm_source=toc&utm_medium=email&utm_campaign=toc_348_63_2&utm_content=etoc_springer_20220301


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 to 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% 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 multipoint line FLDI.

Item URL in elib:https://elib.dlr.de/148740/
Document Type:Article
Title:A low-effort and inexpensive methodology to determine beam separation distance of multi-foci FLDI
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Ponchio Camillo, GianninoUNSPECIFIEDhttps://orcid.org/0000-0002-2178-0777UNSPECIFIED
Wagner, AlexanderUNSPECIFIEDhttps://orcid.org/0000-0002-9700-1522UNSPECIFIED
Date:1 March 2022
Journal or Publication Title:Experiments in Fluids
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In ISI Web of Science:Yes
Page Range:pp. 1-13
EditorsEmailEditor's ORCID iDORCID Put Code
Publisher:Springer Nature
Keywords:interferometry, velocimetr, FLDI, Multi-foci FLDI, Blast waves, hypersonic flow, HEG, turbulent boundary layer
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Transportation
DLR - Research area:Raumfahrt
DLR - Program:R RP - Space Transportation
DLR - Research theme (Project):R - Reusable Space Systems and Propulsion Technology
Location: Göttingen
Institutes and Institutions:Institute for Aerodynamics and Flow Technology > Spacecraft, GO
Deposited By: Wagner, Alexander
Deposited On:15 Mar 2022 14:16
Last Modified:12 May 2023 13:06

Repository Staff Only: item control page

Help & Contact
electronic library is running on EPrints 3.3.12
Website and database design: Copyright © German Aerospace Center (DLR). All rights reserved.