The free hypersonic jets can be found in several technological applications and even in astrophysical observations. This article is mainly devoted to explain an experiment about visualizations and measurements on free hypersonic jets extending on length scales in the order of hundreds of initial diameters and traveling in a medium not necessarily made of the same gas of the jets. The experiments are performed by means of special facilities where the jet Mach numbers and the jet-to-ambient density ratios can be set independently of each other, what permits the investigation of a wide parameters range in the relevant physics. The Mach number of the jets ranges from 5 to 20 and the jet-to ambient density ratio, which plays an important role in the jets morphology, can be set from 0.1 up to values exceeding 100. The present setup produces the jets by means of a fast piston system (for high Mach numbers) or injection valves (for low Mach numbers), both coupled with de Laval nozzles. The visualizations and measurements are based on the electron beam technique: the jets are weakly ionized, then a fast CMOS camera captures images that are analyzed by image processing techniques. A sample of the results obtained by this experimental system is included at the end of this work.

AN EXPERIMENTAL SETUP FOR VISUALIZATIONS ANDMEASUREMENTS ON FREE HYPERSONIC JETS / Marco, Belan; Mohsen, Mirzaei; Sergio DE, Ponte; Tordella, Daniela. - ELETTRONICO. - 25, 01056 (2012):(2012). (Intervento presentato al convegno Experimental fluid mechanics 2011 tenutosi a Jičín, Czech Republic nel 22 - 25 November, 2011) [10.1051/epjconf/20122501056].

AN EXPERIMENTAL SETUP FOR VISUALIZATIONS ANDMEASUREMENTS ON FREE HYPERSONIC JETS

TORDELLA, Daniela
2012

Abstract

The free hypersonic jets can be found in several technological applications and even in astrophysical observations. This article is mainly devoted to explain an experiment about visualizations and measurements on free hypersonic jets extending on length scales in the order of hundreds of initial diameters and traveling in a medium not necessarily made of the same gas of the jets. The experiments are performed by means of special facilities where the jet Mach numbers and the jet-to-ambient density ratios can be set independently of each other, what permits the investigation of a wide parameters range in the relevant physics. The Mach number of the jets ranges from 5 to 20 and the jet-to ambient density ratio, which plays an important role in the jets morphology, can be set from 0.1 up to values exceeding 100. The present setup produces the jets by means of a fast piston system (for high Mach numbers) or injection valves (for low Mach numbers), both coupled with de Laval nozzles. The visualizations and measurements are based on the electron beam technique: the jets are weakly ionized, then a fast CMOS camera captures images that are analyzed by image processing techniques. A sample of the results obtained by this experimental system is included at the end of this work.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/2498341
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