Electronic microwelding power generator for fabricating hot wire probes used in fluid flow studies

The most reliab1e instrumnent to measure the turbulence13; characteristics is the hot wire anemometer, which has acquired importance as an experimental tool in the rapid progress of knowledge in aerodynamics and fluid dynamics. There are definite advantages for the use of hot wire anemometer over other instruments. The hot wire sensing element has dimentions small enough (dia of wire 2 to 10 micrometer and lenght of the wire 1 to 2 mm) to measure flow properties at a quot;pointquot; in usual flow fields and to produce negligible disturbances to the flow. The responce of a compensated hot wire anemometer hasbecome good enough for turbulence studies even in supersonic flows where frequences of 100 Kc/s or more are important. The hot wire method is practicable because, the lag in response at high frequences can be easily compensated electronically to give flat response to as much as 500/2, where M is the time consultant of the hot wire