🤖 AI Summary
This work addresses the challenge in aerodynamic inverse design, where high-dimensional geometry and computationally expensive simulations hinder the simultaneous optimization of performance and geometric plausibility. To overcome this, the authors propose a unified framework that integrates optimal design points with design distributions by combining optimization and guided generative modeling. Key innovations include a novel loss function for cost predictor training, a density gradient-based optimization strategy, and an efficient approximate conditional covariance estimation algorithm that enables a guidance generation framework without additional training. The approach is implemented with OpenFOAM simulations and offline reinforcement learning, and validated through 3D-printed wind tunnel experiments. It demonstrates significant performance improvements on both 2D control tasks and high-fidelity 3D benchmarks for automotive and aerospace applications, showcasing both effectiveness and practicality.
📝 Abstract
Inverse design with physics-based objectives is challenging because it couples high-dimensional geometry with expensive simulations, as exemplified by aerodynamic shape optimization for drag reduction. We revisit inverse design through two canonical solutions, the optimal design point and the optimal design distribution, and relate them to optimization and guided generation. Building on this view, we propose a new training loss for cost predictors and a density-gradient optimization method that improves objectives while preserving plausible shapes. We further unify existing training-free guided generation methods. To address their inability to approximate conditional covariance in high dimensions, we develop a time- and memory-efficient algorithm for approximate covariance estimation. Experiments on a controlled 2D study and high-fidelity 3D aerodynamic benchmarks (car and aircraft), validated by OpenFOAM simulations and miniature wind-tunnel tests with 3D-printed prototypes, demonstrate consistent gains in both optimization and guided generation. Additional offline RL results further support the generality of our approach.