This paper applies the meshfree Smoothed Particle Hydrodynamics(SPH)method with Graphical Processing Unit(GPU)parallel computing technique to investigate the highly complex 3-D dam-break flow in urban areas including underground spaces.Taking the advantage of GPUs parallel computing techniques,simulations involving more than 107particles can be achieved.We use a virtual geometric plane boundary to handle the outermost solid wall in order to save considerable video card memory for the GPU computing.To evaluate the accuracy of the new GPU-based SPH model,qualitative and quantitative comparison to a real flooding experiment is performed and the results of a numerical model based on Shallow Water Equations(SWEs)is given with good accuracy.With the new GPU-based SPH model,the effects of the building layouts and underground spaces on the propagation of dambreak flood through an intricate city layout are examined.
