The C²A²S²E department’s main activity is the development of numerical methods and processes for the multi-disciplinary simulation and optimization of aircraft. In addition to the development of physical models for complex flows and cutting-edge solution algorithms, the department is also active in the development of efficient optimization strategies covering all relevant disciplines, as well as developing surrogate models of higher fidelity methods. The customization of numerical methods for optimal efficiency on high-performance computer clusters is of particular importance to the department. The hybrid flow-solver developed at C²A²S²E is routinely used for a wide range of simulations in both research and industry. The department is also involved in the development of a system for the multi-disciplinary simulation and design of wind turbines.