This book presents cutting-edge research from the 14th ERCOFTAC Workshop on Direct and Large Eddy Simulation, offering a unified look at how high-fidelity computational methods are being used to investigate complex flow phenomena across aerodynamics, compressible and multiphase flows, combustion, and turbomachinery. It highlights studies that apply DNS and LES to real-world challenges—such as analyzing vehicle aerodynamics, understanding shock-wave and turbulent boundary-layer interactions, modeling particle-laden flows with advanced data-driven breakage models, and exploring how turbulent spray flames influence nanoparticle synthesis—while also presenting foundational advances in turbulence modeling, statistical analysis, and numerical methods like remeshed vortex techniques.