# REPORT 1174 ## THE STRUCTURE OF TURBULENCE IN FULLY DEVELOPED PIPE FLOW By JOHN LAUFER National Bureau of Standards ## SUMMARY Measurements, principally with a hot-wire anemometer, were made in fully developed turbulent flow in a 10-inch pipe at speeds of approximately 10 and 100 feet per second. Emphasis was placed on turbulence and conditions near the wall. The results include relevant mean and statistical quantities, such as Reynolds stresses, triple correlations, turbulent dissipation, and energy spectra. It is shown that rates of turbulent-energy production, dissipation, and diffusion have sharp maximums near the edge of the laminar sublayer and that there exist a strong movement of kinetic energy away from this point and an equally strong movement of pressure energy toward it. Finally it is suggested that, from the standpoint of turbulent structure, the field may be divided into three regions: (1) Wall proximity where turbulence production, diffusion, and viscous action are all of about equal importance; (2) the central region of the pipe where energy diffusion plays the predominant role; and (3) the region between (1) and (2) where the local rate of change of turbulent-energy production dominates the energy received by diffusive action.# REPORT 1174 ## THE STRUCTURE OF TURBULENCE IN FULLY DEVELOPED PIPE FLOW By JOHN LAUFER National Bureau of Standards ## SUMMARY Measurements, principally with a hot-wire anemometer, were made in fully developed turbulent flow in a 10-inch pipe at speeds of approximately 10 and 100 feet per second. Emphasis was placed on turbulence and conditions near the wall. The results include relevant mean and statistical quantities, such as Reynolds stresses, triple correlations, turbulent dissipation, and energy spectra. It is shown that rates of turbulent-energy production, dissipation, and diffusion have sharp maximums near the edge of the laminar sublayer and that there exist a strong movement of kinetic energy away from this point and an equally strong movement of pressure energy toward it. Finally it is suggested that, from the standpoint of turbulent structure, the field may be divided into three regions: (1) Wall proximity where turbulence production, diffusion, and viscous action are all of about equal importance; (2) the central region of the pipe where energy diffusion plays the predominant role; and (3) the region between (1) and (2) where the local rate of change of turbulent-energy production dominates the energy received by diffusive action.