Correcting for particle counting bias error in turbulent flow
Abstract
An ideal seeding device is proposed generating particles that exactly follow the flow out are still a major source of error, i.e., with a particle counting bias wherein the probability of measuring velocity is a function of velocity. The error in the measured mean can be as much as 25%. Many schemes have been put forward to correct for this error, but there is not universal agreement as to the acceptability of any one method. In particular it is sometimes difficult to know if the assumptions required in the analysis are fulfilled by any particular flow measurement system. To check various correction mechanisms in an ideal way and to gain some insight into how to correct with the fewest initial assumptions, a computer simulation is constructed to simulate laser anemometer measurements in a turbulent flow. That simulator and the results of its use are discussed.
 Publication:

Wind Tunnel Seeding Systems for Laser Velocimeters
 Pub Date:
 October 1985
 Bibcode:
 1985wtss.nasa...13E
 Keywords:

 Bias;
 Correction;
 Counting;
 Error Analysis;
 Flow Distribution;
 Flow Measurement;
 Laser Anemometers;
 Particle Production;
 Velocity Measurement;
 Computerized Simulation;
 Error Correcting Devices;
 Turbulent Flow;
 Instrumentation and Photography