中华鲟产卵场的三维水流特性分析

摘要

Chinese sturgeon is facing a serious population resource problem.Identifying the water flow characteristics of Chinese sturgeon spawning ground can provide more accurate and reasonable technical parameters for rehabilitating the spawning ground and protecting natural population.In this paper,Chinese sturgeon spawning ground under the Gezhouba dam was taken as the simulation reach,fluid dynamics software Fluent was used to simulate a three dimensional water flow process of the simulation reach in the spawning period.Change rule and value range of velocity,vorticity and turbulence kinetic energy in different functional zones of spawning ground was analyzed.The results show that hydraulic parameters for different functional zones are placed in different range.The bottom flow velocity is basically greater in the spawning area than that in the sowing spawn area,and the smallest is in the attachment & hatch area.The vertical variation of flow velocity in the sowing spawn area is bigger than that in the spawning area.Vorticity is basically greater in the sowing spawn area than that in the spawning area,and the smallest is in the attachment & hatch area.Strongly turbulent flow is located substantially in the upper and middle part of water column.Bottom turbulent kinetic energy has little change in various functional areas,especially the value in the attachment & hatch area is not obviously different from that in the sowing spawn area.Water flow condition of the spawning ground under Gezhouba dam is not particularly conducive to fertilization and spread of Chinese sturgeon eggs.In order to clarify the spawning characteristics of Chinese sturgeon,we need to carry out numerous simulation,comparison and analysis.%中华鲟面临严重的种群资源问题,明确中华鲟产卵场的水流特性可为产卵场修复和自然种群挽救提供更准确合理的技术参数.研究运用流体力学软件Fluent模拟葛洲坝坝下中华鲟产卵场产卵时期的三维水流过程,分析流速、涡量、湍动能等水力学参数在产卵场不同功能区内的变化规律和取值范围.结果表明:不同功能区水力学参数的取值范围不同,对比各取值范围发现底层流速基本满足产卵受精区＞播卵区＞着卵孵化区,而播卵区的流速垂向变化幅度总体大于产卵受精区;涡量基本满足播卵区＞产卵受精区＞着卵孵化区;湍动激烈区基本位于水体的上中层,底层湍动能在各功能区变化不大,特别是着卵孵化区的湍动能没有明显区别于播卵区.葛洲坝坝下产卵场水流状况不是特别有利于中华鲟卵的受精散播和附着孵化,为了进一步明确中华鲟产卵繁殖的水流特性,需要继续开展大量的模拟、对比分析工作.