Each color shows the data from one stationary measurement volume. Note data at y > 10um above the wall.
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The SM3PR(Position-Resolving)LDV is an advanced measurement technique that was developed and proven by AUR personnel. The technique is loosely based upon the dual-beam LDV concept, but with improvements to measure particle position in the measurement volume in addition to the usual measurements of velocity vectors.
The AUR SM3PRLDV is the only measurement system that is capable of measuring three-components of velocity and position over the dynamic ranges that high Reynolds number turbulent flows exhibit. The measurements are resolved in both time and space for a wide range of flow scales, even in very near-wall regions of bounded flows.
The PRLDV technique is a new tool for researchers seeking to understand fundamental phenomena related to drag, flow- generated noise, and turbulence structure in a wide range of flows.
Highly resolved near-wall turbulence measurements
The PRLDV is the only instrument in the world that can deliver high Reynolds number velocity profile measurements in 3-D flows to within 10s of microns from a surface.Using advanced instrument configurations and custom, exclusive signal processing techniques, the PRLDV sets a new standard in near-wall flow characterization.
Velocity spectral measurements
All velocity components are measured at very high data rates (~100Hz/(m/s) in low-speed flows). This allows very near-wall characterization of the frequency content of turbulent flows.Measurements of cross-spectra are possible and may be used to explore the coherency of pairs of velocity components. These measurements indicate the ranges of frequencies where significant anisotropy exists. No other technique can be used this effectively for near-wall velocity spectral studies.
Velocity gradient statistics measurements
Research has shown (Lowe and Simpson 2008a) that time-series data from the PRLDV may be used to estimate the instantaneous velocity gradients in the flow.