Measurements of the turbulent energy dissipation rate

The one-dimensional surrogate for the dimensionless energy dissipation rate C-epsilon is measured in shear flows over a range of the Taylor microscale Reynolds number R-lambda, 70less than or similar toR(lambda)less than or similar to1217. We recommend that C-epsilon should be defined with respect to an energy length scale derived from the turbulent energy spectrum. For R(lambda)greater than or similar to300, a value of C(epsilon)approximate to0.5 appears to be a good universal approximation for flow regions free of strong mean shear. The present results for C-epsilon support a key assumption of turbulence-the mean turbulent energy dissipation rate is finite in the limit of zero viscosity. (C) 2002 American Institute of Physics.