Description:
We have prepared two sets of experiments in wave flume to demonstrate resonance phenomena in laboratory conditions and to model effects occurring in natural conditions. The first set was performed to investigate nonlinear wave run-up on the beach caused by harmonic wave maker located at some distance from the shore line. It is revealed that under certain wave excitation frequencies a significant increase in run-up amplification is observed [ 1]. It is found that this amplification is due to the excitation of resonant mode in the region between the shoreline and wave maker. Frequency and magnitude of the maximum amplification are in good correlation with the numerical calculation results represented in the recently published paper [ 2]. The second set of experiments was performed to study resonance effects due to parametric excitation of edge waves. It is known that surface waves propagating toward the shore can excite edge waves propagating along the shore line. Although the edges wave amplitude decreases in an offshore direction they may contain enough energy to be responsible for erosion of the shore and generate so-called cusps [ 3]. We investigate parametric mechanism of such generation when plane surface wave with frequency Ω excite edge wave with frequency Ω/ 2. It is shown that parametric generation of edge waves can amplify run-up up to two times.