Photographing Cavitation on Model Propellers

The paper describes the technique and apparatus used to obtain both still and cine records of cavitating model propellers in a cavitation tunnel. An electronic flash circuit is used which gives a microsecond region, 400 joule flash from four gas discharge tubes in series. A simple power stroboscope, also having four tubes in series, is used for the cine work and provides a 16 joule flash up to a maximum of 40 flashes per second. The flash duration in each case has been measured and compared with that of a single microsecond region tube. The problem of the positioning of the light sources is discussed and the method used to obtain clear water in the tunnel circuit is described.