Fluid physics instrumentation study. Part 1: System aspects

Diagnostic methods relevant to the investigation of fluid physics experiments in micro-g were assessed to select instrumentation for a multiuser facility. Many considerations, rooted in power, weight, safety, operation, etc., are shown to have an impact on instrument performance. An optical diagnosis system is defined. The only real limitation imposed on the system is the absence of a parallel illumination beam with a cross-section comparable to the size of the experiment volume. This feature is less important for the classes of problems represented by fluid physics. A diffusely illuminated experiment volume which is a necessary condition for the visualization of edge and gradient distributions was chosen. The system provides the flexibility to install a variety of diagnostic aids. It also offers the possibility to investigate phase objects by interferometry, with a field-of-view 1 sq cm. Since the interesting part of an object can, in most cases, be identified a priori, this restriction on field-of-view is not considered to be a major demerit.