| 徐敏,曾光明,黄国和,何理.非线性随机水环境风险模型[J].水利学报,2005,36(1):0056-0061 |
| 非线性随机水环境风险模型 |
| Nonlinear stochastic water environmental risk model |
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| DOI： |
| 中文关键词: Shastry模型 非线性 随机扰动 水环境风险 |
| 英文关键词: Shastry model nonlinear stochastic vibration water environment risk |
| 基金项目: |
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| 摘要点击次数: 2743 |
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| 中文摘要: |
| 本文在Shastry非线性水质模型的基础上，引入随机力的概念，建立水环境系统的随机微分方程。通过数值方法求解多维随机的偏微分方程得到概率密度分布函数，从而实现对水环境风险的初步研究，获得污染物超标风险率与超标时间长短的关系。通过实例计算表明：(1)不同的扰动强度对超标风险值影响不同，当扰动强度为0.5时，即使河段经过了18d的净化分解后，该河段的超标风险率仍高达65%；(2)BOD5削减50%或者DO初始浓度增加 50%，将大大降低河段的超标风险值，对应不同的扰动强度，超标风险值将分别下降16%左右或23%左右；(3)对非线性条件下的多维随机微分方程分别采用显式差分和隐式差分进行求解，结果表明两种方法均能反映风险变化曲线的趋势，对超标风险值影响不大。 |
| 英文摘要: |
| On the basis of Shastry's nonlinear water quality model, the concept of stochastic force is introduced to establish the stochastic differential equation for water environment. The probability density distribution function is deduced by numerically solving the multi-dimension stochastic partial differential equation. The relationship between the risk and duration of pollution exceeding standard is established accordingly. The calculation of case study shows that the stochastic variation intensity affects the risk, and the reductions of BOD5 or initial concentration of DO result in remarkable reduction of risk. The explicit scheme and implicit scheme are applied to solve the nonlinear stochastic differential equation respectively. The result shows that the difference of risk variation tendency calculated by different scheme is not significant. |
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