Explore turbulence closure models in fluid dynamics through this 34-minute video lecture. Delve into the complexities of modeling turbulent fluid dynamics, focusing on bulk quantities and low-resolution approximations. Understand the importance of "closing" reduced approximations of the Navier-Stokes equations to maintain physical accuracy. Learn about leading approaches, including Reynolds Averaged Navier Stokes (RANS) equations and Large Eddy Simulations (LES). Discover key concepts such as averaged velocity fields, mass continuity equations, Reynolds stresses, turbulent kinetic energy, and eddy viscosity modeling. Compare RANS and LES approaches, and gain insights into their applications in high-performance and scientific computing. Presented by Steve Brunton, this comprehensive overview covers topics from basic principles to advanced modeling techniques, providing a solid foundation for understanding turbulence closure models in fluid dynamics.