Law of the wall

law of the wall, horizontal velocity near the wall with mixing length model

In fluid dynamics, the law of the wall (also known as the logarithmic law of the wall) states that the average velocity of a turbulent flow at a certain point is proportional to the logarithm of the distance from that point to the "wall", or the boundary of the fluid region. This law of the wall was first published in 1930 by Hungarian-American mathematician, aerospace engineer, and physicist Theodore von Kármán.[1] It is only technically applicable to parts of the flow that are close to the wall (<20% of the height of the flow), though it is a good approximation for the entire velocity profile of natural streams.[2]

  1. ^ von Kármán, Th. (1930), "Mechanische Ähnlichkeit und Turbulenz", Nachrichten von der Gesellschaft der Wissenschaften zu Göttingen, Fachgruppe 1 (Mathematik), 5: 58–76 (also as: “Mechanical Similitude and Turbulence”, Tech. Mem. NACA, no. 611, 1931).
  2. ^ Mohrig, David (2004). "Conservation of Mass and Momentum" (PDF). 12.110: Sedimentary Geology, Fall 2004. MIT OCW. Retrieved 2009-03-27.