1D-3D coupled simulation method of hydraulic transients in ultra-long hydraulic systems based on OpenFOAM

Transients in hydraulic systems are normally simulated by one-dimensional (1D) method of characteristics (MOC). When local three-dimensional (3D) flow patterns have crucial impacts on the system characteristics, 3D computational fluid dynamics (CFD) simulation should be incorporated. Since simulating an entire long CFD is unrealistic, we proposed several 1D-3D coupled methods. However, methods difficult to apply and popularise because most codes inaccessible implementation details unclear. Consequently, utilised open source toolbox OpenFOAM develop a proved its feasibility applying it analysing practical problems. This paper describes implementations water compressibility, coupling, gas-liquid simulation, dynamic mesh; shows their verifications accuracy benchmark cases; demonstrates simulations closing opening processes 194 km conveyance system. The gate chamber maximum/minimum head envelopes along tunnels, which support design optimisation project, presented. It shown that computationally efficient accurate, can applied transient analyses for systems, pumped-storage power stations, etc.