ABSTRACT
Flow velocity and its nondimensional form known as the Mach number are some of the most important parameters in fluid flow analysis. Flow velocity can be measured by many techniques. The principle underlying laser Doppler anemometer is that a moving particle illuminated by a light beam scatters light at a frequency different from that of the original incident beam. The Doppler shift in frequency occurs when a particle moves with a component of its velocity in the direction of the light beam. Flow velocity and its nondimensional form known as the Mach number are some of the most important parameters in fluid flow analysis. Some of the popularly used techniques are velocity measurement through pressure measurements, through optical properties like Doppler shift using laser Doppler anemometer, through measurement of the vortex shedding frequency and through heat transfer principle, using hot-wire anemometer.
