ESTIMATION OF THE KOLMOGOROV CONSTANT (C-0) FOR THE LAGRANGIAN STRUCTURE-FUNCTION, USING A 2ND-ORDER LAGRANGIAN MODEL OF GRID TURBULENCE

We review Sawford's [Phys. Fluids A 3, 1577 (1991)] second-order Lagra ngian stochastic model for particle trajectories in low Reynolds numbe r turbulence, showing that it Satisfies a well-mixed constraint;for th e (hypothetical) case of stationary, homogeneous, isotropic turbulence in which the joint probability density function for the fixed-point v elocity and acceleration is Gaussian. We then extend the model to deca ying homogeneous turbulence and, by optimizing model agreement with th e measured spread of tracers in grid turbulence, estimate that Kolmogo rov's universal constant (C-0) for the; Lagrangian velocity structure function has the value of 3.0+/-0.5. (C) 1995 American Institute of Ph ysics.