Note that the flow stream, including velocity, is symmetric about the center of the cylinder. Figure 2 shows the flow about a cylinder under these assumptions.įigure 2: Theoretical Flow Around a Cylinder.
Most flow analysis neglected this phenomenon out of necessity, thus adding a large degree of uncertainty to the calculations that would lead to predicting drag. Prior to Prandtl’s recognition of the boundary layer in fluid flow around an immersed body, scientists were unclear about the impact of viscosity and friction at the solid surface. It started with Ludwig Prandtl’s identification of the phenomenon. The ramifications of this development are far reaching, from minimizing drag in automobiles to improving cooling of turbine blades ( see “Turbine Benefit”), as industries strive for greater energy efficiency and fuel economy.Įngineers and scientists have been aware of flow separation for more than 100 years. “The work they did isolates the steady parameters from the craziness of unsteady flow.” a movie,” notes Mike Peery, president of TecPlot, Inc. unsteady flow can be compared to looking at a static image vs. However, after five years of research, a team of scientists from MIT, San Diego State University, and United Technologies has developed a breakthrough methodology that allows engineers to precisely determine the location and angle of flow separation in both 2D and 3D as well as steady and unsteady flow conditions. One of the more important yet difficult calculations to understand is the precise behavior of the breakaway of fluid from walls. Whether the domain is material stress or fluid flow, any data is only as good as the engineer’s ability to interpret and apply it. In any simulation, obtaining accurate results is only half the battle. Breuer, Department of Fluid Mechanics, Helmut-Schmidt University Hamburg. Figure 1: CFD Results of Flow Separation Behind a Cylinder.
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