Fig. 6: Results at 53 kHz at different depths.
From: Elastic orbital angular momentum transfer from an elastic pipe to a fluid
Frequency domain real pressure field (left column) and phase (right column), at 53 kHz. a, b FEM Simulation with x−y measurement plane at z = 0.9 m (according to the coordinate system adopted in Figs. 3b & 7) i.e., at the submerged end of the pipe. c, d Experimental results at the acoustic centre of the microphone, z = 0.92 m as in Fig. 2. e, f, g, h are subsequent measurements at x−y planes 6 mm deeper: z = 0.926 m and z = 0.932 m, respectively. The dashed black circles show the inner and outer radii of the pipe, highlighting the divergence of the acoustic beam as it propagates deeper in the fluid.
