In-Flow Acoustic Power and Intensity Fields Measurements with a 2D LDV System

Characterization of an acoustic liner by means of Laser Doppler Velocimetry in a subsonic flow

“…The extraction of the acoustic velocity was a first step leading to the assessment of more elaborate acoustic quantities. Subsequently, active intensity and acoustic impedance measurements [13][14][15] were carried out with the same experimental setup. These measurements were achieved by using simultaneously a laser velocimeter and a microphone equipped with a cone.…”

“…(12) and (14) are resolved. Static pressure measurements are also performed so the Eulerian perturbation of pressure can be assessed with expression (15). Its value is compared to the one measured by a microphone flush-mounted to a wall of the duct.…”

“…These perturbations are considered for a given fluid particle rather than for a given position. As Laser Doppler Velocimetry (LDV) brought encouraging results for aeroacoustic measurement [13][14][15]20], it was chosen for building a new aeroacoustic metrology. The purpose of this paper is to introduce these theoretical and experimental solutions and to show how they can bring some interesting pieces of information about propagation with flow, in a noninvasive way.…”

Laser Doppler Velocimetry for Joint Measurements of Acoustic and Mean Flow Velocities : LMS-based Algorithm and CRB Calculation

“…Their results showed a good agreement between the theory and the experiment but this probe cannot be considered as nonintrusive. LDV has also been used by adapting the slotting technique to estimate the acoustic particle velocity in a turbulent flow [15] with a 2D-LDV velocimeter. The acoustic impedance was estimated by means of a LDV probe and with a microphone probe and the different results were compared.…”