近43年北大西洋海浪场与AO的相关性研究

利用来自ECMWF的ERA-40 wave reanalysis海浪资料,分析了近43年北大西洋海浪场与AO(北极涛动——Arctic Oscillation)的关系。研究发现如下主要特征:1、北大西洋海域的海表风场和(风浪、涌浪、混合浪)海浪场与AO有着密切的关系,且存在3.71年左右的共同周期和26年的长周期震荡;2、通过交叉谱分析发现,在波数k=7(周期T=3.71年)这一频率上,AO、海表风速、波高振动的凝聚是显著的。     

利用WW3模式实现中国周边海域波浪能流密度数值预报——以2次冷空气过程为例

近年来中国在海洋能研究方面得到快速发展,但目前为止尚未实现波浪能的预报。本研究以T639预报风场作为WW3(WAVEWATCH-III)海浪模式的驱动场,对2013年3月发生在中国周边海域的2次冷空气过程所致海浪场进行模拟,充分利用来自朝鲜半岛、日本、台湾岛的观测资料,检验WW3模式对能流密度的预报能力,实现了波浪能流密度的数值预报,为海浪发电、海水淡化等波浪能开发工作提供保障。研究表明:1)以T639预报风场驱动WW3海浪模式,可以较好地预报冷空气影响下的中国周边海域波浪能流密度。无论预报值与观测值在曲线走势上,还是从相关系数、偏差、均方根误差、平均绝对误差等定量来判断,预报能流密度都具有较高精度,其中在朝鲜半岛、日本周边海域的预报效果好于台湾岛周边的预报效果。2)在冷空气影响下,中国周边海域的波浪能流密度伴有明显的增幅。在渤海、渤海海峡、黄海北部,由于海域狭小,海浪得不到充分成长,能流密度的增幅相对较小,大值区的范围也相对较小;冷空气进入黄海中部、东海后,能流密度迅速增加,高值中心可达80 kW/m以上;冷空气进入南海后,虽然也使得能流密度明显增大,但由于南海纬度较低,冷空气南下行进至南海后强度大为减弱,能流密度的大值区范围较东海缩小。     

Hydroelastic Investigation on A Pile Breakwater Integrated with A Flexible Tail for Long-Wave Attenuation

A novel concept of wave attenuator is proposed for the defense of long waves, through integrating a flexible tail to the lee-side surface of a pile breakwater. The flexible tail works as a floating blanket made up of hinged blocks, whose scale and stiffness can be easily adjusted. A two-phase-flow numerical model is established based on the open-source computational fluid dynamics (CFD) code OpenFOAM to investigate its wave attenuation performance. Incompressible Navier—Stokes equations are solved in the fluid domain, where an additional computational solid mechanics (CSM) solver is embedded to describe the elastic deformation of the floating tail. The coupling of fluid dynamics and structural mechanics is solved in a full manner to allow assess of wave variation along the deforming body. The accuracy of the numerical model is validated through comparison with experimental data. Effects of the flexible tail on performance of the pile breakwater are investigated systematically. Dynamic behaviours of the tail are examined, and characteristics of its natural frequency are identified. For safety reasons, the wave loads impacting on the main body of the pile breakwater and the stress distribution over the tail are specially examined. It is found that both the length and stiffness of the tail can affect the wave-attenuation performance of the breakwater. A proper choice of the length and stiffness of the tail can greatly improve the long-wave defending capability of the pile breakwater. The maximum stress over the flexible tail can be restrained through optimising the deformation and stiffness of the tail.

     

陇东盆地地热系统地温场特征及平凉地热勘查评价

甘肃陇东盆地属鄂尔多斯盆地西南部,包括西缘冲断带、天环向斜与东部斜坡带等次级地质构造单元,赋存白垩系自流盆地型地下热水和奥陶系碳酸盐岩岩溶型水,盆地内大地热流值普遍偏低。本文就平凉地热资源勘查和钻探验证的基础上,从区域地热地质构造、深部构造、盆地结构、地温场特征对地热赋存条件、影响温度的因素和热源机制进行了分析,对地热资源开发前景进行探讨和评价。