Instability Criteria for Vehicles in Motion Exposed to Flood Risks

Flooded roads have somewhat become a norm to the society and among the damages that floods can pose, there are fatalities and harm caused to people. Floating debris such as vehicles, manipulated by floodwaters could potentially cause harm not only to the public safety but also towards the public and private-owned properties. In the past, research on vehicle's instabilities have been solely dedicated to static vehicles which are normally translated as vehicles parked on road surface. A vehicle when exposed to floodwater get influenced by different hydrodynamic forces and becomes prone to different instability modes, namely sliding, floating and toppling. Outcomes on such modes are somehow recognised in the works on static vehicles, but the mechanics of a moving vehicle under such influences have not been studied. Herein the influence of floodwater flows on the vehicle attempting to cross a flooded path (partial submergence) is presented. With that regards, a non-stationary model vehicle with the scale ratio of 1:10 (Perodua Viva) was used and a series of experiments were conducted. Moreover, a new formula to estimate the incipient velocity for a moving vehicle has been introduced and the prediction accuracy of the proposed formula has been validated using experimental data. Measurements were taken including approaching velocities and water depths, through which the instability was computed.