An inertial range crossover in structure functions

Experimental and numerical data within the traditional inertial subrange de fined by the third-order structure function is used to study higher-order s caling exponents for the longitudinal and transverse structure functions. F or 262 <R-lambda< 3200, these exponents converge only over larger scales, r >r(S), where r(S) is between eta and lambda and has an R-lambda dependence . Below these scales, scaling exponents cannot be determined for any of the structure functions without resorting to procedures such as extended self- similarity (ESS). With ESS, different longitudinal and transverse higher-or der exponents are obtained that are consistent with earlier results. The re lationship of these statistics to derivative and pressure statistics, to tu rbulent structures and to length scales is discussed. (C) 2001 American Ins titute of Physics.