Research on Vehicle Lateral Stability Under Flow Impact During Wading

The growing frequency of extreme rainfall events attributable to global climate change has heightened concerns regarding flood-related hazards to road traffic safety. Under wading conditions, vehicles become susceptible to lateral sliding, flotation, or rollover when exposed to lateral hydrodynamic impacts, jeopardizing both occupant safety and infrastructure integrity. Previous studies have primarily focused on longitudinal sliding instability—such as the critical flow velocity for vehicle motion initiation and buoyancy-related submersion depth—under forward or backward flow, employing theoretical analyses and flume experiments. However, research on the dynamic response of vehicles under lateral flow, the underlying mechanisms of lateral skidding, and multi-degree-of-freedom instability modes remains relatively limited. To address this gap, this study establishes a multi-body vehicle dynamics model for lateral flow conditions, incorporating lateral hydraulic forces and tire-road friction factors. It analyzes the vehicle's critical lateral slip force, reveals the impacts of water depth and flow velocity on stability, and proposes a critical flow velocity criterion for lateral slip based on hydrodynamic perception. The research further investigates the effects of varying water depths and slip velocities on vehicle wading performance. The findings indicate that increased water depth corresponds to a significant reduction in the critical lateral sliding velocity. Moreover, the most critical condition for lateral instability arises when the flow impinges perpendicularly on the vehicle's side profile. These outcomes provide a theoretical framework and technical basis for enhancing vehicle safety in flood-prone environments. Theoretically, they offer new insights into the hydrodynamic mechanisms governing lateral instability. Technically, they deliver quantifiable criteria and a modeling approach that can inform the design of more robust vehicles and improve the accuracy of safety assessments, ultimately mitigating the risk of hydrodynamic-induced failures.