| 摘要 |
PROBLEM TO BE SOLVED: To reduce a correction amount of a tube port end and to accurately measure even if a volume of a sample is near an inner volume of a container by constituting a Helmholtz resonator by using a container and two or more acoustic tubes connected to the container. SOLUTION: A volume measuring device 1 utilizing a resonance frequency change such as a Helmholtz resonation or the like for measuring a volume of, for example, a road recessed part Q is constituted by mounting, for example, 24 acoustic tubes 3 at a ground container 8 opened only at its bottom brought into contact with a road. A white noise or the like is radiated from a sound source 4, a Helmholtz resonance is detected by a microphone or the like to measure a resonance frequency by a predetermined method. A volume of the recess part Q is obtained by a predetermined calculation from the resonance frequency having a predetermined relation with the volume in the container 8. The number of the tubes 3 is increased to reduce an opening end correction amount in the resonance without difficulty of acoustically detecting it due to a decrease in the frequency, thereby improving its measuring accuracy.
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