info:eu-repo/semantics/article
Visualization of a supersonic air micro jet by methods of dual-hologram interferometry
Autor
J.GUADALUPE VELASQUEZ AGUILAR
ALVARO ZAMUDIO LARA
MIGUEL OCTAVIO ARIAS ESTRADA
Resumen
Visualization and investigation of supersonic
air micro jets (SAMJ) as weak phase objects present
serious problems when done through classical visualizing
methods. Usage of advanced holographic interference
techniques would make the study and evaluation of
characteristic densities, density gradients and jet’s structure
(weak shocks followed by expansion waves) more
successful. It should be remarked, that the applications of
Mach-Zehnder (reference) and shear dual-hologram techniques,
which were performed in earlier works, have been
done separately and have a demonstrative character. In
the present paper, the authors have tried to apply both the
dual-hologram techniques, simultaneously. This approach
makes it possible to measure the same phase object under
study by reference beam and shear interference techniques
using only Mach-Zehnder holograms. Finally, experimental
data obtained from both the techniques were
numerically compared and found to be more applicable. It
was first experimentally shown that sensitivity of shear
interference approach during evaluations of radial component
of density gradients in a micro jet can be enhanced
by using the technique of re-recording holograms. The
effect of fast transition to a transonic regime accompanied
by expansion and later on with disintegration of a jet was
observed and jet’s densities and radii in transition region
were evaluated. As a whole, method of co-joint application
of reference beam and shear dual-hologram interferometry
has shown its self-descriptiveness, flexibility
and utility for optical diagnostics of a weak gas dynamic
micro object, the supersonic air micro jet.