An acoustic technique for Lagrangian velocity measurements

Nicolas Mordant (1, 2) , Pascal Metz (2) , Jean-François Pinton (2) , Olivier Michel (2)

1 LPS - Laboratoire de Physique Statistique de l'ENS
2 Phys-ENS - Laboratoire de Physique de l'ENS Lyon

Ultrasonic transducers array can be used to track solid particles advected by a turbulent flow. The simultaneous use of four linear antennas of transducers gives the 3D position of the particles. The extraction of the Doppler frequency shift gives a precise estimation of velocity components. We describe the principle of the technique, the signal conditioning and the acquisition schemes. We show briefly the performances of the technique applied to a turbulent flow at high Reynolds number. The dynamical range of the measurement is over 55 dB and the frequency response spans over 2 decades. These performances allow us to investigate the inertial time scales of Lagrangian turbulence.

Mots clés: Turbulence; Acoustics; Lagrangian

Domaines: Dynamique des Fluides [physics.flu-dyn]

Nicolas Mordant, Pascal Metz, Jean-François Pinton, Olivier Michel. An acoustic technique for Lagrangian velocity measurements. Review of Scientific Instruments, 2005, 76 (1), pp.025105. ⟨ensl-00180416⟩