Streamlines is a Geometry Nodes system designed to simulate aerodynamic flow around 3D objects. It creates procedural streamline trails that mimic wind tunnel visualizations without relying on physics simulations or external plugins. The system evaluates the mesh to calculate flow paths, allowing users to animate the airflow over time or freeze the generation for still renders. The setup includes customizable color-coding that maps to resistance, curvature, or speed. The tool is provided as a .blend file containing the complete node network alongside a sample demo scene.