The LDV's potential in understanding turbulent structure
Abstract
In order to investigate the possible biases that can arise in an individual realization laser Doppler velocimeter (LDV), a turbulent flow model based on a combination of two-dimensional Rankine combined vortices of various strengths is proposed. For flow parameters selected to fit experimental data, and for a uniform distribution of particles within each eddy and among eddies, individual particles are modeled as they pass through the LDV problem volume. Various dimensionless combinations of the LDV parameters, the turbulent flow parameters, and the particle parameters are identified and related to ten different forms of signal biasing which result from the particle trajectory through the probe volume. A computer program is used to predict the LDV data under a given set of operating conditions, and this result is compared to the flow conditions of the model. It is shown that very large biases exist for highly turbulent flows and for component measurements at a large angle from the mean flow direction.
- Publication:
-
Laser Anemometry
- Pub Date:
- 1976
- Bibcode:
- 1976laan.symp....1F
- Keywords:
-
- Computerized Simulation;
- Flow Measurement;
- Laser Doppler Velocimeters;
- Turbulence Meters;
- Turbulent Flow;
- Velocity Measurement;
- Computer Programs;
- Jet Flow;
- Mathematical Models;
- Near Wakes;
- Particle Trajectories;
- Performance Prediction;
- Turbulence Models;
- Two Dimensional Flow;
- Vortices;
- Instrumentation and Photography