Experimental data on the Reynolds number dependence of the area-averaged turbulent kinetic energy K and dissipation rate are presented. It is shown that while in the interval ReD > 105 the total kinetic energy scales with friction velocity (K/u*2 = const), a new scaling law K/U2∝ K/(u*2ReD θ) = const (θ≈1/4) has been discovered in the interval ReD < 105. It is argued that this transition is responsible for the well-known change in the scaling behaviour of the friction factor observed in pipe and channels flows at ReD≈ 105.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering