Abstract
The visualization of air flow is often made by the use of oil mist. The mist condenses on the wall of wind tunnel. It is not an easy task to clean up walls of a large wind tunnel. In order to avoid this trouble we have developed a method of visualization by the use of small water droplets. The water vapor produced in a boiling-water container goes through a thick bed of lumps of dry ice (carbon dioxide).
Water mist is injected into the air flow. The dense smoke comparable to conventional oil mist has been obtained. Water droplets eventually vaporize and there is no contamination in wind-tunnel. Another method of visualization has been tried by filling a shallow box with water mist. If we make the mist a little cooler than surrounding atmosphere, the mist settles in the box. This box can be used as a towing tank, namely, various kinds of solid body can be moved in the box and the flow picture is taken. We visualized the flow field around model automobile of various shapes.
