Fluid measurements
 

hi guys, i dont know much about experimental measurements.

i was wondering where is the best place to get a very simple guide to the main measuring techniques - LDA / Raman / LIF / Rayleigh.

if any body could give the basic ideas of these methods and where they are used it would be great. otherwise any online refernces or text books would be useful.

thanks.

Re: Fluid measurements
 

How detailed and accurate do you need that info to be? For a quick and dirty overview you can try google. If you are not familiar with the concepts, you will first want to find out what the physical principles are, underlying each of the methods. For example, Laser Doppler Anemometry (LDA), as the name suggests, applies the Doppler frequency shift to measure the velocity of a particle. Imagine two laser beams intersecting at some point in space (the measurement location), conditioned to create an interference pattern of some known frequency at that point. A particle that passes through this focus will reflect the light at a frequency (color) proportional to its speed. An optical sensor detects all incoming light bursts and spits out the speed obtained from the measured frequency. You will remember the phenomenon (Doppler effect) from high school physics: Depending on direction and speed of a fire truck passing you, you will hear the siren at a different frequency. LDA makes use of that phenomenon also observed with electromagnetic waves (e.g. light), not just sound waves.

Re: Fluid measurements
 

hi mani, thankyou. that is about the level of detail i need.

do you also understand the basic principles of raman and rayleigh and LIF measurements.

any similar comments on these would be great.

thanks again.