在一个二维街道峡谷中,对流动和分散的局部和上风温度分层的数值模拟
1College of Modern Logistics, Shanxi Vocational University of Engineering Science and Technology, Taiyuan, Shanxi, China.
PloS one
|June 24, 2024
概括
这项研究将雷诺兹-平均纳维尔-斯托克斯 (RANS) 和大模拟 (LES) 进行了比较,用于在城市峡谷中建模热效应. LES精确模拟了流量和污染物分散,而RANS则在热分层效应方面扎.
科学领域:
- 环境流体动力学 环境流体动力学
- 城市气象城市气象学
- 计算流体动力学的流体动力学.
背景情况:
- 热效应,包括温度分层和局部加热,显著影响城市峡谷中的空气流和污染物分散.
- 对这些热效应的准确建模对于了解城市空气质量和制定有效的缓解策略至关重要.
研究的目的:
- 评估雷诺兹-平均纳维尔-斯托克斯 (RANS) 和大模拟 (LES) 方法在模拟2D峡谷中热效应下的流动和分散的性能.
- 将模拟结果与风洞实验数据进行比较.
主要方法:
- 模拟使用RANS和LES计算流体动力学方法进行.
- 分析了包括流场,动动能,温度,热量流和污染物度在内的关键参数.
- 结果与风洞实验数据进行了验证.
主要成果:
- 由于模拟流量分离和Boussinesq模型的局限性,RANS方法高估了加热的影响,导致流量,温度和度的预测不准确.
- LES准确地复制了流量分离,结构和低风速,与实验数据更好地一致.
- 对于屋顶水平的空气交换率,LES的结果与实验数据相差不到5%,污染物度分布几乎相同.
结论:
- 在模拟城市峡谷中受热效应影响的复杂流动和分散现象方面,LES优于RANS,即使在较小的尺度上也是如此.
- 当热分层显著时,RANS方法的适用性有限.
- 对于涉及热效应的精确模拟,建议使用 LES,而对于具有有限计算资源和小温度差异的简单案例,RANS 可能就足够了.
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