水动力条件对嘉陵江重庆主城段藻类生长影响的数值模拟

为研究水动力条件对嘉陵江重庆主城段藻类生长繁殖和富营养化的影响,通过对现有藻类生长率计算式中的流速影响函数进行改进,引入表征藻类生长最佳流速与流速范围的参数,构建了二维非稳态藻类生长动力学模型,并用实测数据以及现有的实验成果对其参数进行率定与优化.针对三峡水库水华高发时段的气候条件和研究河段现有的营养盐状况,就不同水位下的叶绿素a浓度的时空分布进行数值仿真、对可能发生水华的位置和范围进行分析和预测.结果表明,对于嘉陵江重庆主城段,流速在0.04m·s-1左右最有利于藻类的生长繁殖.

Numerical Simulation for Effects of Hydrodynamic Condition on Algae Growth in Chongqing Reaches of Jialing River

By introducing two parameters which express the optimal velocity and the velocity range for alga growth, a new velocity factor was put forward for the formula of alga growth. The 2-D unsteady ecological dynamic model for algae growth was established to analyze the effects of hydrodynamic condition on algae growth in Chongqing reaches of Jialing River. The space-time distribution of concentration for Chl-a was simulated numerically for various water levels under climate condition in the period of high frequency for water blooms in Three Gorges Reservoir and nutrition condition at present. The corresponding location and area of water blooms were forecasted. The results stated that about 0.04 m·s^-1was the optimal velocity for algae growth.