APPLICATION OF FLDV TO THE FLOW CHARACTERISTICS OF STANDING WAVE

摘要

The characteristics of flow fields in the potential regionand bottom boundary layer of finite amplitude standing wavesare investigated experimentally for Ursell number rangingfrom 1.21 to 50.59. Fiber laser Doppler velocimeter (FLDV)was used for quantitative measurement. According to linearstanding wave theory, the nodes and anti-nodes are fixedpoints in the space of wave field and the nodes just locate atthe still wave level. However, these specific points are found tobe not fixed in the wave field, due to tiny period differences ofincident waves generated by a precise wave maker. Therefore,spatial distributions of the highest, lowest, and mean waterlevels in finite amplitude standing waves were measured first.The positions of the maximum and minimum (mean) waveheights were then determined. The characteristics of timehistories of water surface elevation as well as the underlyinghorizontal and vertical velocities, measured along threesections (i.e. the positions of the maximum and minimum(mean) wave heights and the mid-point between them), areelucidated in detail.