含淹没水生植物冠层的水流时均流速分布研究进展

Progress on Velocity Profile in Water Flow with Submerged Vegetation Canopy

大型淹没水生植物冠层可以为各种水生生物提供栖息地、食物和游乐场所,同时也能通过吸收细颗粒污染物和释放氧气等净化水体、提高水质,因而对河流、湖泊和海岸生态环境的保持、修复和改善具有重要意义。其环境水动力学问题已经被全球越来越多的研究所关注,其中一个最基本的问题是水流时均流速的垂向分布,它直接关系到水流的阻力和质量输送。本文将流速分布形式分为三大类:对数分布;具有拐点的反正切和双曲形分布;以及分段叠加混合型分布。分别对这三类分布形式的主要特征和适用特点进行概括性综述,并根据形成的紊动和动量传递机理对其未来发展方向进行展望。该进展综述旨在为水流生态管理和修复工程提供基本思路指导,也方便研究者高效定位科学问题。

Macrophyte of submerged vegetation canopy in water flow can provide habitat, food, and play en-vironment for all kinds of aquatic fauna. It can purify the flow and improve water quality by ab-sorbing fine particles of pollutant and releasing oxygen as well. Consequently, it has substantial significance for river, lake and coast to protect, restore and improve their ecological environments. The issue of environmental fluid mechanics in the submerged vegetated flow has obtained more and more concerns. The vertical profile of the time-averaged mean velocity is one of the funda-mental studies, because it is directly related to the issues of resistance and mass transport in flow. The present paper describes the velocity profile in three catagories: logrithmic law, inverse tan-gential or hyperbolic profile with inflection point, and the superposition of segments of mixing profiles. The main characteristics and application situations of these three profiles are summarized, and the future advances of the development of velocity profile are presented based on its forming mechanics: turbulent structures and momentum mixture. The present paper aims at providing assistances in the management and restoring of the ecological environment for engineers, and in the distinguishment of fundamental scientific issues for researchers.