arXiv:2411.11348physics.flu-dyncs.LG2024-11被引 7

用局部傅里叶神经网络,高效高精度模拟城市三维微气候。

Modeling Multivariable High-resolution 3D Urban Microclimate Using Localized Fourier Neural Operator

  • 引入局部训练与几何编码,提升多变量微气候预测精度。
  • 10米分辨率下60秒内预测误差仅0.35米/秒(风速)和0.30℃(温度)。
  • 单卡32GB GPU实现50倍于传统仿真速度,适合城市规划与碳中和应用。

准确的城市微气候分析对节能城市规划、减碳、公共健康与低空经济发展至关重要。传统计算流体动力学(CFD)耦合风速与温度模拟成本高昂。近年来机器学习为加速城市微气候模拟提供了新路径。傅里叶神经算子(FNO)在预测城市风场速度幅值方面表现优异,但在多变量高分辨率3D微气候预测中存在输出模糊、显存需求高、数据依赖性强三大问题。为此,本文提出局部傅里叶神经算子(Local-FNO),结合局部训练、几何编码与块重叠策略。Local-FNO可在60秒内精确预测超过平均湍流积分时间尺度四倍的快速变化湍流,风速平均误差0.35米/秒,温度误差0.30℃,并准确捕捉由速度-温度相关性表征的湍流通量。在2公里×2公里区域内,可实现10米分辨率的湍流结构解析。模型在单张32 GB GPU上处理1.5亿特征维度,预测速度接近CFD求解器的50倍。相比FNO,Local-FNO预测误差降低23.9%,湍流波动相关性提升47.3%。

原文摘要 · Abstract (English)

Accurate urban microclimate analysis with wind velocity and temperature is vital for energy-efficient urban planning, supporting carbon reduction, enhancing public health and comfort, and advancing the low-altitude economy. However, traditional computational fluid dynamics (CFD) simulations that couple velocity and temperature are computationally expensive. Recent machine learning advancements offer promising alternatives for accelerating urban microclimate simulations. The Fourier neural operator (FNO) has shown efficiency and accuracy in predicting single-variable velocity magnitudes in urban wind fields. Yet, for multivariable high-resolution 3D urban microclimate prediction, FNO faces three key limitations: blurry output quality, high GPU memory demand, and substantial data requirements. To address these issues, we propose a novel localized Fourier neural operator (Local-FNO) model that employs local training, geometry encoding, and patch overlapping. Local-FNO provides accurate predictions for rapidly changing turbulence in urban microclimate over 60 seconds, four times the average turbulence integral time scale, with an average error of 0.35 m/s in velocity and 0.30 °C in temperature. It also accurately captures turbulent heat flux represented by the velocity-temperature correlation. In a 2 km by 2 km domain, Local-FNO resolves turbulence patterns down to a 10 m resolution. It provides high-resolution predictions with 150 million feature dimensions on a single 32 GB GPU at nearly 50 times the speed of a CFD solver. Compared to FNO, Local-FNO achieves a 23.9% reduction in prediction error and a 47.3% improvement in turbulent fluctuation correlation.

微气候模拟神经算子城市规划高分辨率

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