Inertial-buoyant coupling and bi-directional flow effects on plume deflection in inclined tunnel fires under natural ventilation

• Reveals plume deflection is driven by inertial forces from both airflow sides. • Introduces modified Richardson number ( Ri’ ) for coupling buoyancy with asymmetric inertial forces. • Identifies critical Ri’ = 16.0 ± 1.5 as deflection threshold via buoyancy–inertia interaction. • Develops a robust Ri’ -based model to predict plume deflection angle. • Conventional test configuration is improper in simulating tunnel fire in weak wind scene. Plume deflection in inclined tunnel fires is a critical yet inadequately understood phenomenon that directly influences smoke movement and evacuation safety. This study conducts a series of high-fidelity numerical simulations to investigate the onset conditions and…

• NN
  National Natural Science Foundation of China

  Awards: 52478422, 52408439
• CP
  China Postdoctoral Science Foundation

  Award: GZC20241518
• FR
  Fundamental Research Funds for the Provincial Universities of Zhejiang

  Award: 226-2024-00099