Measurement of a flow-velocity profile using a laser Doppler velocimetry coupled with a focus tunable lens

Abstract

This paper reports on the measurement of a flow-velocity profile using a laser Doppler velocimetry (LDV) system having a focus tunable lens (FTL). In the system, the FTL is installed in the transmitting optics of the LDV; therefore, it can measure the flow velocity profile by changing the measurement position without any mechanical scanning system. To demonstrate the concept of the technique, the velocity profile measurement of Poiseuille flow was conducted, and the measured velocity profile showed good agreement with the theoretical value.