Experimental results on the pressure dependence of the minnaert resonance frequency for three different gases in water

We present new experimental results for the pressure dependence of the natural oscillation frequency of the sound emitted from gas bubbles released in water. The experiments cover a wide range of pressures corresponding to depths from sea surface down to almost 400 meters. We compare our previously reported results using only nitrogen gas, with new results using helium, and carbon dioxide. This also allows for testing how the oscillation frequency depends on the polytropic index of the gas in question. We compare the experimental results with those predicted by the Minnaert formula for the oscillation frequency of gas bubbles in water. The results show good agreement between the experimental results and those predicted by the Minnaert formula. We can use the estimated polytropic gas index to decide which gas we have.