Michel Philbert

Wind Tunnel Experimental Study Of Optical Beam Degradation Through Heterogeneous Aerodynamic Flows

This paper deals with the influence of aerodynamic disturbances on the quality of images obtained by an airborne optical system. A wind-tunnel experiment has been carried out in order to simulate aero-optical phenomena in transsonic and supersonic flows. The characterization of such effects is obtained by studying the propagation of a laser beam (λ : 0.63 pa) through optical aerodynamic configurations. The influences of turbulent mixing zone and shock waves have been studied. Each aerodynamical configuration has been qualified by both Schlieren visualization and wall pressure probing test. For each configuration, images are recorded and then processed to obtain point spread functions (PSF), optical transfer functions (OTF), modulation transfer function (MTF) and Wiener spectrum of the images. This study should lead to match optical and aerodynamical considerations in designing future airborne imaging systems.

Optical Fibers Application To Visualization Of Flow Separation Inside An Aircraft Intake In Wind Tunnel.

We describe an experiment to visualize air flow separation in an aircraft air-intake. This experiment was realized in a large industrial wind-tunnel. It uses optical fibers to bring a laser beam into the model and an optical fiber endoscope to visualize images of the phenomenon. Some pictures showing changes of the air flow separation are presented for several aerodynamic conditions.