Acoustical streaming causes movement of particles toward which direction?

Acoustical streaming causes movement of particles toward which direction?

• A. Toward the beam
• B. Away from the beam
• C. In all directions randomly
• D. Not influenced by the beam

Answer: (A)

Acoustical streaming creates a steady fluid flow driven by the absorption of acoustic energy, which drags suspended particles along the direction of the ultrasound beam. The momentum transfer from the wave acts along the beam’s propagation axis, causing the bulk fluid flow and the particles within it to move toward the beam. It’s not random or directed away; near boundaries you may see local circulations, but the overall tendency is particles moving in the direction of the beam.

Acoustical streaming creates a steady fluid flow driven by the absorption of acoustic energy, which drags suspended particles along the direction of the ultrasound beam. The momentum transfer from the wave acts along the beam’s propagation axis, causing the bulk fluid flow and the particles within it to move toward the beam. It’s not random or directed away; near boundaries you may see local circulations, but the overall tendency is particles moving in the direction of the beam.