Silt Erosion in Hydraulic Turbines: The Need for Real-Time Numerical Simulations

Direct numerical simulations of quartz particles, given a turbulent stationary velocity field, are per formed in "real time" on a Silicon Graphics work station. Interaction of the surrounding flozu on spherical particles is taken into account by a modi fied version of the Basset-Boussinesq-Oseen equa tion, including nonlinear resistance. Boundary con ditions (walls) are modeled with the use of reflection laws. Interactions between particles are neglected. The velocity field has been pre-computed with the k—∈ model over different geometries. Second-order accuracy numerical implementation and error esti mation are discussed. Impacts on surfaces are ac counted for by means of direction and kinetic energy of incident particles. The areas with the highest probability of damage are then mapped. Real-time high-quality interactive graphics are an important aspect of this useful numerical tool.