A Lagrangian numerical method, known as Smoothed Particle Hydrodynamics (SPH), has been applied to simulate flash floods triggering and resulting propagation. As test case, the authors consider the northern slope of Monte Sant’Angelo di Cava mountain, where a fast pyroclastic slide left three casualties in the city of Nocera Inferiore (Southern Italy), on March 4th, 2005. The physical domain is discretized with a collection of so called “particles” without connectivity law among them, avoiding problems related with grid refinements. While boundary particles are fixed over time, computing particles are free to move in response to external and internal forces such as gravity and pressure. More specifically, computing particles are all initially “frozen” . Once a particle is “unfrozen” it starts moving and it triggers a change in pressure in the neighbouring particles: when a pressure threshold plim is reached, other particles are set in motion and the movement evolves. Runout velocity is controlled by handling the shear stress TAUbed with the fixed bed. Varying the location of the triggering point, the pressure threshold plim and the shear stress TAUbed allow to perform a sensitivity analysis on the resulting flooded area.
Simulating Flash Floods with SPH. II Imprints workshop. Barcelona (Spain).
VICCIONE, GIACOMO;BOVOLIN, Vittorio
2010
Abstract
A Lagrangian numerical method, known as Smoothed Particle Hydrodynamics (SPH), has been applied to simulate flash floods triggering and resulting propagation. As test case, the authors consider the northern slope of Monte Sant’Angelo di Cava mountain, where a fast pyroclastic slide left three casualties in the city of Nocera Inferiore (Southern Italy), on March 4th, 2005. The physical domain is discretized with a collection of so called “particles” without connectivity law among them, avoiding problems related with grid refinements. While boundary particles are fixed over time, computing particles are free to move in response to external and internal forces such as gravity and pressure. More specifically, computing particles are all initially “frozen” . Once a particle is “unfrozen” it starts moving and it triggers a change in pressure in the neighbouring particles: when a pressure threshold plim is reached, other particles are set in motion and the movement evolves. Runout velocity is controlled by handling the shear stress TAUbed with the fixed bed. Varying the location of the triggering point, the pressure threshold plim and the shear stress TAUbed allow to perform a sensitivity analysis on the resulting flooded area.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
