涌浪对风浪能量影响的实验研究

Laboratory Research on the Influence of Swell on Wind Wave Energy

在实验室风浪水槽中进行纯风浪和混合浪波面位移观测,研究波长较长的规则波对风浪能量的影响。本文用混合浪和纯风浪中的风浪显著波的零阶谱矩之比代表混合浪中的风浪与纯风浪能量之比,并以此表征涌浪对风浪能量的影响。研究了该能量比随涌浪波陡S、风区x、波龄倒数u/C、涌浪频率与纯风浪谱峰频率之比fs/fwp的变化规律。结果表明,涌浪对风浪能量的抑制作用随涌浪波陡的增加、波龄倒数的增大及涌浪频率与纯风浪谱峰频率之比的增大而增强。发现该能量比依赖于无因次量R=(1+80(πS)2)1.9fs在实验室风浪水槽中进行纯风浪和混合浪波面位移观测,研究波长较长的规则波对风浪能量的影响。本文用混合浪和纯风浪中的风浪显著波的零阶谱矩之比代表混合浪中的风浪与纯风浪能量之比,并以此表征涌浪对风浪能量的影响。研究了该能量比随涌浪波陡S、风区x、波龄倒数u/C、涌浪频率与纯风浪谱峰频率之比fs/fwp的变化规律。结果表明,涌浪对风浪能量的抑制作用随涌浪波陡的增加、波龄倒数的增大及涌浪频率与纯风浪谱峰频率之比的增大而增强。发现该能量比依赖于无因次量R=(1+80(πS)2)1.9〔fs/fwp〕0.9〔u/C〕0.27,并拟合得到2者的经验关系。此外,本文实验还发现,在某些情况下,涌浪的存在使风浪能量增加。

Laboratory experiments were conducted in a wind-wave flume during which the surface elevation of wind waves with and without mechanically-made long waves were measured. The 0th-order spectral moments of the dominant wind waves, either in the mixed waves or in the pure wind waves, were calculated, and the ratio of the two was employed to characterize the change in wind wave energy caused by these swell. The ratio of wind wave energy with and without swell varies with the swell steepness （ S ）, fetch （x）, inverse wave age （u/C） and the ratio（f,/fwp） of the spectral peak frequency of the wind waves to the swell frequency. As the steepness（s）, inverse wave age（u/C） and the ratio of frequency（f,/fwp） increased, the ratio of wind wave energy with and without swell decreased. It was also found that the dependence of the ratio of wind wave energy with and without swell on the factors mentioned above could be described by its relationship with the dimensionless parameter R=（1＋80（πS）^2^1.9（fs/fwp）^0.9（u/C）^0.27 . Additionally, the wind wave energy in mixed wave might be greater than the pure wind waves in some special cases, and such a phenomenon was not discussed by former researcher.