Katepalli R. Sreenivasan, physicist at New York University, presents a seminar at the Institute for Advanced Study on decaying turbulence, the behavior a fluid shows once it has been stirred and then left alone in a sealed box. He reports results from large numerical simulations of the Navier-Stokes equations run in a triply periodic domain, comparing the outcomes against classical turbulence theory dating to the 1940s and against Alexander Migdal's more recent theoretical framework from the 2020s. The talk, part of the IAS Joint SNS/SOM High Energy Theory Seminar series, works through how simulated turbulence decays over time, what statistical features persist, and where the newer theory agrees or diverges from decades-old predictions. It runs 68 minutes and assumes familiarity with fluid dynamics and the Navier-Stokes equations, pitched at a research audience rather than a general one.