This horn is very promising for the task of matching the high-power acoustic transducers with large cross-sections to liquid loads at cavitation.  To illustrate this point: the total acoustic power transmitted into water at cavitation by this horn made of titanium alloy, taking into account the fatigue strength limitation and the existence of the maximum allowed output diameter (due to the λ/4 constraint), under normal hydrostatic pressure is about 5 kW at a frequency of 20 kHz.  This value of the power of the acoustic radiation is close to the theoretically attainable maximum under the given conditions for any metallic rod horn.

The existence of the maximum allowed output diameter does not permit further increase of the total transmitted power even for the case of the barbell horn.  To alleviate this problem, at Industrial Sonomechanics LLC, we have developed several modified versions of this device that can circumvent this limitation.

The modifications described below utilize the principle of increasing the output surface in some way that does not generate non-axial vibration modes.  The first modification, called “long barbell horn”, uses additional acoustic radiation via the lateral surface of the horn.  It capitalizes on the fact that no restriction exists neither on the length of the horn nor on the shape of its lateral surface.  Taking this into account, we have developed a special resonant element with a gain factor of unity, but with a strongly radiating lateral surface.  We call this the “spool horn”. 

Figure 5 shows the schematic of this horn along with the plots of the vibration amplitude distribution and the deformation along the horn’s length. Here: V(z) – amplitude of vibration velocity; e(z) – deformation amplitude; k – wave number; Ln – vibration node position; L – vibration antinode position;  L1, L2, L3, L4, L5 – corresponding element lengths; D0, D1, D2 – cross-section diameters.

FIGURE 5

FIGURE 6