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使用MIDAS-400用户化数据采集系统在江苏王港潮滩进行了现场观测,获取了多层位的流速和悬沙浓度的同步数据,并将高分辨率的压力波动记录转换为波浪数据.分析结果表明:潮滩区域的表观粗糙长度远大于底床沉积物粒径量级,接近于沙纹高度;浪流联合作用产生的底部切应力大于单纯的潮致切应力,是导致紊动混合作用和再悬浮作用加剧的主要因素;潮周期内观测到多个悬沙峰值,主要与涨潮前锋的水体强烈紊动和再悬浮有关,平流作用、极端天气状况(如暴雨、强风)也是不可忽视的重要因素;在涨潮或落潮时间异常延长、水流成为准单向流的较长时段内,可产生较大的悬沙净输运量.研究表明,MIDAS-400系统可以实现浪流联合作用下的潮滩水动力和沉积动力特征的高分辨率观测,所获数据适用于物质输运过程和机制的分析.
Using the MIDAS-400 customized data acquisition system, the on-site observation was conducted at Wangang tidal flat in Jiangsu Province to obtain synchronous data of velocity and suspended sediment concentration at multi-level positions and to convert high-resolution pressure fluctuation records into wave data. The results show that the apparent roughness length of the tidal flat area is much larger than the grain size of sediment, which is close to the sand height. The combined shear stress at the bottom of the tidal flat is larger than the pure tidal shear stress, And the main factors that aggravate the action and resuspension. During the tidal cycle, a number of suspended sediment peaks were observed, which were mainly related to the strong turbulence and resuspension of the water bodies in the rising tide front. Advection and extreme weather conditions (such as heavy rain and strong winds) were also not neglected Of the main factors; in the high tide or ebb abnormal extension of the water flow become a quasi-one-way flow in a long period of time, can produce a larger net suspended sediment transport.Research shows that, MIDAS-400 system can achieve the combined action of the wave High-resolution observations of hydrodynamic and sediment-bearing dynamic characteristics of the tidal flats and the data obtained are suitable for the analysis of material transport processes and mechanisms.