Data processing of single burst signals from laser Doppler velocity sensors for turbulent flow measurements

Flow separation and its control is a persistent topic of fluid dynamic research. The paper describes the development and implementation of a novel optical signal processing system to measure liquid flow velocities with a high spatial resolution in the order of 20 μm. The principles of Laser Doppler Anemometry coupled with signal processing algorithms are used to quantify the fluid flow velocities in the vicinity of a flow controlling device called Lorentz Force Actuator. The signal processing routines are tested on the bench using a Field Programmable Gate Array (FPGA) using LabVIEW from National Instruments. The LabVIEW code is ported to a PC based Data Acquisition Card for real time signal processing and correlation measurements in highly turbulent flows. The aim is to achieve the same performance as commercial systems, which are not applicable in conjunction with the novel laser Doppler sensors, while maintaining the high precision and flexibility of the propriety signal processing techniques.