Statistical Description of Turbulent Flows A Short Review in Memory of Rudolf Friedrich

摘要

In this article we review two different approaches to the statistical description of turbulent flows in terms of evolution equations for probability density functions (PDFs), namely a description of the turbulent cascade by a FokkerPlanck equation, as well as kinetic equations in terms of the theoretical framework of the Lundgren-Monin-Novikov hierarchy. In both cases conditional averages are the building blocks that allow to make a connection to experimental or numerical data. Professor Dr. Rudolf Friedrich made central contributions to both of these approaches, which we want to highlight here.