The Founder of Modern Fluid Dynamics Ludwig Prantdl

THE FOUNDER OF MODERN FLUID DYNAMICS: LUDWIG PRANTDL A fluid is defined as a substance that does not have any determined shape and is deformed continuously by a shear force, thus it can be said that fluid mechanics is considered as a part of physics which is concerning about gases, liquids and plasmas, in the other words, no solid phases.[1] Modern fluid mechanics is based on Continuum Hypothesis. This hypothesis assumes that a matter is continuous, hence while a matter is examined, atomic structure is not regarded- because if a matter is analyzed at a microscopic scale, the matter will be observed as discrete- and macroscopic scale is preferred instead of microscopic scale.[2] Fluid mechanics can be divided into some subtitles, and†¦show more content†¦The outer part of boundary layer area can be assumed inviscid like before Prandtl. The boundary layer is a very thin layer around the solid body. Prandtl explained the boundary layer with the help of adhesion. The velocity difference between solid body and fluid is zero, in the other words there is no slip condition in between since, they are interlocked by adhesion. In the light of this information, the velocity gradient of flow changes from the surface of solid body to the outer line of boundary layer, and this means shear stress demonstrates a vast alteration. Therefore, the friction drag force that observed on the surface of solid body cannot be ignored.[5] Another Prandtl’s explanation is flow separation. Some layers of fluid start to make rotational motion and then, strive for passing to free fluid flow. The separation starts at a determined point. This point- is called separation point- is specified by external conditions completely and it is occurred by friction which observed in the boundary layer. The layers of fluid in which is rotational motion forms a separation region (it can be called dead region) that has a low energy. As a result of the flow separation, pressure distribution on the surface of solid body changes and a pressure drag in which is the direction of stream lines of free flow or friction drag appears owing to the new pressure distribution.