Flow Visualisation Techniques in Wind Tunnels. Part I – Non optical Methods

 

Slavica Ristić

 

In this article, an attempt is made to describe and review the most widely used methods for flow visualization. The first part describes the basis and applications of different visualization methods (non optical) for subsonic and supersonic flow in wind and water tunnels: direct injection methods, (smoke, dye, fog and different small particles) visualization methods by electrolytic and photochemical dye production, gas and hydrogen bubbles, special techniques, flow visualization by tufts, oil, liquid crystals, pressure and temperature sensitive paints.         
A considerable attention is paid to flow visualization techniques performed in VTI wind and water tunnels and almost all presented photos have been recorded during tests in laboratories of VTI.
Optical methods and their application for compressible flow visualization will be given in the second part of the article.

 

Key words: flow visualization, wind tunnel, water tunnel, research method.