Affiliations: Università di Napoli "Federico II",
Dipartimento di Scienza ed Ingegneria dello Spazio "Luigi G. Napolitano", P.le
V. Tecchio 80, 80125 Napoli, Italy
Abstract: The Unsteady Computerized Thermographic Technique (UCTT) provides
patterns of the Stanton number on a body surface. These patterns are the
imprints of the flow field. The UCTT already proved to be a powerful, not
intrusive diagnostic tool both for the visualization and the strength
evaluation of vortical structures on the lee-side surface of delta wing models.
The patterns are obtained by processing, by an "ad hoc" mathematical model, the
temperature time evolution of the model surface. The temperature is measured at
a distance by a thermocamera. In previous tests on delta wing models, the used
thermocamera showed a limitation in the optics and did not provide an
appropriate space resolution and, therefore, a detailed visualization of whole
vortical structure. In the present paper this limitation has been overcome. The
optics improvement has doubled the space resolution of thermocamera. Tests,
made at angle of attack of 6-deg. and Mach number of 1.92, verified that this
improvement was substantial. In fact, the detection of secondary vortex on
delta wing model and strake vortices on a double delta wing model was made
possible. Unfortunately, it was not possible to visualize details of vortical
structure on a Gothic wing model. Tests showed that vortical patterns were
similar to the one on delta wing model.