ENGINEERING AND CFD

Today, hydropower is the most important and widely used renewable energy source. Due to the strong increase of fluctuating renewable energies, a great amount of regulating power is necessary in the net, which is mainly available from hydropower. As a consequence, the hydraulic turbines are very often operated in extreme off-design conditions. As a result, very complex flow structures and frequent flow instabilities occur in the, which can cause severe dangerous oscillations in the entire hydroelectric plant. Apart from causing damage, the oscillations can be noisy enough to disturb people living in the neighbourhood of the plant. For an accurate design, it is essential to predict the flow phenomena accurately and as quickly as possible. There are various methods to simulate an entire hydroelectric power plant, but if someone wants to resolve the complex flow well, the use of sophisticated mathematical models is very important (by Large Eddy Simulation (LES) and Very Large Eddy Simulation). These turbulence models are very promising for better understanding of the flow and consequently for an improved hydropower plant design and optimization. Thanks to supercomputers, simulations with highly accurate numerical schemes and very sophisticated turbulence models are possible. The aim of the research is to optimize hydropower plants for stability and reliability in order that hydropower can play an essential role for integrating volatile renewable energy source into the electrical net.