In the paper we carried out two experiments: periodic linear waves and solitary waves. In part 1, a small scale experiment associated with the generation and propagation of linear sinusoidal waves in two-layered fluids was conducted. A ratio of amplitude of free-surface wave to interfacial-surface wave was measured by adjusting the frequency of wave maker and position of wave maker was changed from lower layer to upper layer. This ratio is compared to two analytic wave modes: barotropic mode and baroclinic mode which are induced by linear wave theory. In a perspective of wave mode, oscillating of wave maker generates two wave modes but the primary mode would be different according to variation of frequency. To confirm this phenomenon, two modes were decoupled by using two snapshots with different time. The results of observation are explained in terms of the amplitude of each mode, wave energy, wave energy flux and wave profile. In this experiments thickness ratio: "h" _"2" /"h" _"1" was 0.28 and frequency changed from 0.3 Hz to 1.2 Hz. In part 2, we present experimental results about the generation and propagation of solitary waves with free-surface in two-layered fluids. Two methods: dam breaking and pushing a panel are used to generate solitary waves. Before the experiments in two layer fluids, preliminary experiments in homogeneous fluids were carried out to make sure the result of two layer fluids. In two layer fluids, two modes are observed: baroclinic and barotropic modes. For small amplitude, wave experimental results well matched Peter and Stoker’s theory in both modes. However, for large amplitude, the interfacial surface waves are close to the Kdv-mKdv equation in baroclinic mode. Particular attention is paid to the measurement of the variation of wave heights according to their propagation speeds and this is compared to the existing analytical solitary wave solutions.
이 논문에서는 이층유체에서의 선형 주기파와 고립파에 관한 실험을 진행하였다. 파트 1에서는 이층유체에서의 선형주기파를 다루었으며, 이층유체에서는 밀도가 다른 두 유체의 특성에 의해 baroclinic mode와 barotropic mode가 발생할 수 있으며 각 모드별 크기는 주파수와 조파기의 위치에 따라 영향을 받는다. 따라서 조파기의 위치와 주파수를 변화시켜가며 표면파와 내부파의 파고 변화를 관찰하였다. 이 ㄸㅒ의 주파수는 0.3Hz부터 1.2Hz까지 변화시키며 실험하였으며 조파기의 위치는 표면층 내부 경계층 아래층에 위치시켜 작동하였다.
파트 2에서는 고립파를 다루었으며 dam breaking 방법과 piston type wave maker를 통해 고립파를 발생시켰으며 고립파에서의 barotropic mode와 baroclinic mode를 실험관찰하였다. 이러한 실험결과를 Peter and Stoker`s theory 와 mKdv식과 비교분석 하였으며 파고의 형태 phase speed 표면파와 내부파의 비를 이론과 실험결과를 비교 분석하였다.
