Rooftop Wind Field Reconstruction Using Sparse Sensors: From Deterministic to Generative Learning Methods

TL;DR

This paper demonstrates that deep learning models, especially when trained with mixed wind directions and optimized sensor placement, significantly improve rooftop wind field reconstruction accuracy from sparse sensor data, aiding urban air mobility safety.

Contribution

It introduces a comprehensive learning framework combining experimental data, deep learning models, and sensor optimization for accurate rooftop wind field reconstruction from sparse sensors.

Findings

Deep learning models outperform Kriging interpolation in wind field reconstruction.

Mixed wind-direction training significantly enhances model performance.

Sensor placement optimization improves robustness under sensor perturbations.

Abstract

Real-time rooftop wind-speed distribution is important for the safe operation of drones and urban air mobility systems, wind control systems, and rooftop utilization. However, rooftop flows show strong nonlinearity, separation, and cross-direction variability, which make flow field reconstruction from sparse sensors difficult. This study develops a learning-from-observation framework using wind-tunnel experimental data obtained by Particle Image Velocimetry (PIV) and compares Kriging interpolation with three deep learning models: UNet, Vision Transformer Autoencoder (ViTAE), and Conditional Wasserstein GAN (CWGAN). We evaluate two training strategies, single wind-direction training (SDT) and mixed wind-direction training (MDT), across sensor densities from 5 to 30, test robustness under sensor position perturbations of plus or minus 1 grid, and optimize sensor placement via Proper Orthogonal Decomposition with QR decomposition. Results show that deep learning methods can reconstruct rooftop wind fields from sparse sensor data effectively. Compared with Kriging interpolation, the deep learning models improved SSIM by up to 32.7%, FAC2 by 24.2%, and NMSE by 27.8%. Mixed wind-direction training further improved performance, with gains of up to 173.7% in SSIM, 16.7% in FAC2, and 98.3% in MG compared with single-direction training. The results also show that sensor configuration, optimization, and training strategy should be considered jointly for reliable deployment. QR-based optimization improved robustness by up to 27.8% under sensor perturbations, although with metric-dependent trade-offs. Training on experimental rather than simulated data also provides practical guidance for method selection and sensor placement in different scenarios.