{"ID":2848168,"CreatedAt":"2026-06-01T04:54:23.091178241Z","UpdatedAt":"2026-06-01T04:54:23.091178241Z","DeletedAt":null,"paper_url":"https://arxiv.org/abs/2510.26718","arxiv_id":"2510.26718","title":"Reducing base drag on road vehicles using pulsed jets optimized by hybrid genetic algorithms","abstract":"Aerodynamic drag on flat-backed vehicles like vans and trucks is dominated by a low-pressure wake, whose control is critical for reducing fuel consumption. This paper presents an experimental study at $Re_W\\approx 78,300$ on active flow control using four pulsed jets at the rear edges of a bluff body model. A hybrid genetic algorithm, combining a global search with a local gradient-based optimizer, was used to determine the best-performing jet actuation parameters in an experiment-in-the-loop setup. The cost function was designed to achieve a net energy saving by simultaneously minimizing aerodynamic drag and penalizing the actuation's energy consumption. The optimization campaign successfully identified a control strategy that yields a drag reduction of approximately 8.8%. The best-performing control law features a strong, low-frequency actuation from the bottom jet, which targets the main vortex shedding, while the top and lateral jets address higher-frequency, less energetic phenomena. Particle Image Velocimetry analysis reveals a significant upward shift and stabilization of the wake, leading to substantial pressure recovery on the model's lower base. Ultimately, this work demonstrates that a model-free optimization approach can successfully identify non-intuitive, multi-faceted actuation strategies that yield significant and energetically efficient drag reduction.","short_abstract":"Aerodynamic drag on flat-backed vehicles like vans and trucks is dominated by a low-pressure wake, whose control is critical for reducing fuel consumption. This paper presents an experimental study at $Re_W\\approx 78,300$ on active flow control using four pulsed jets at the rear edges of a bluff body model. A hybrid ge...","url_abs":"https://arxiv.org/abs/2510.26718","url_pdf":"https://arxiv.org/pdf/2510.26718v2","authors":"[\"Isaac Robledo\",\"Juan Alfaro\",\"Víctor Duro\",\"Alberto Solera-Rico\",\"Rodrigo Castellanos\",\"Carlos Sanmiguel Vila\"]","published":"2025-10-30T17:20:44Z","proceeding":"physics.flu-dyn","tasks":"[\"physics.flu-dyn\",\"cs.NE\",\"math.OC\"]","methods":"[]","has_code":false}