Experimental data for the analyses.

Flash flood in mountainous regions have caused significant damage worldwide in recent years, impacting and destroying structures. The impact load of flash flood is the key factor in the process of destruction. In this study five existing models for impact pressure calculation were compared and analyzed based on experimental data. What’s important, combining two existing models, a new model considering both hydrodynamic and hydrostatic pressure was proposed. The results showed that the relative error of empirical coefficient was lowered from 16.2% to 7.09% in the condition of Froude number less than 2, and lowered from 10.7% to 9.9% when the Froude number exceeded 2 in the new calculating model. Besides, the distribution of fluid impact and the maximum pressure point against a passable obstacle was discussed. The findings of this research could provide ideas for structure design to withstand the flooding impact.