流砂量測定器の試作研究(2)

Abstract

In this study, some measuring techniques of sediment discharge are discussed.In the previous paper, the author devised a direct measuring system composed of afixed sieve, a sand pump, rotating baskets and a load cell. In this paper, it is im-proved to a system composed of a trommel and a tipping bucket suspended by aload cell. For relatively small gravel and sand, this system works well.It is difficult, however, to apply direct measuring methods for coarser gravel, and it is necesarry to devise some indirect measuring techniques.Among some indirect methods, an acoustic one is discussed in this paper. Theoscillation of air confined in a pipe is detected by a microphone mounted on aninside wall of the pipe. The amplitude is proportional to the momemtum of theparticle which impacts the pipe. If the particle velocity is known or constant, it ispossible to estimate the particle mass from the amplitude with some calibration.Two sets of calibration were carried out using a small flume. It is expected thatthis method will be also applicable to field measurement.