Abstract
Sound characteristics, such as the scoustic power level (PWL), the A-weighted sound level (L (A)) and the power spectrum of flow in a water-cushion-type drops were studied in fields.
The results of this study are summarized as follows:
1) It was found that both the scoustic power level and the A-weighted sound level increase linearly with the drop of energe (ED) per unit width canal and the energe loss (ΔE) increase for a range of ED=170-5490 (N·m/s·m), ΔE=0.46-2.25 (m), respectively.
2) The ratio of diminishment of A-weighted sound level in the traverse direction of the water-cushion-type drops tends to be higher than that in either upstream or downstream direction. And, value of the ratio of diminishment of A-weighted sound level in the traverse direction was high about 15% in comparison with the downstream direction.
3) From the relationship between the power spectrum and the frequency, the spectrum of flow in the water-cushion-type drops tends to be approximate to white type noise.
