Influence of the axisymmetric contraction ratio on freestream turbulence
Abstract
The effect of axisymmetric contractions of a given shape and of contraction ratios c = 11, 22, 44.5, 64, and 100 on the freestream turbulence of an incompressible flow has been studied experimentally with hotwires. It is found that the longitudinal and lateral kinetic energies of turbulence increase along the contraction. The monotonic increase of the longitudinal turbulent kinetic energy with increasing c is in contrast with the linear (BatchelorProudmanRibnerTucker) theory. The variation of the lateral turbulent kinetic energy with c is in qualitative agreement with the theory. Linear theory overpredicts the decrease in the longitudinal turbulence intensity with increasing c and underpredicts the decrease in the lateral turbulence intensity with increasing c. For the given flow tunnel, it is found that a contraction ratio c greater than about 45 is not greatly effective in reducing longitudinal turbulence levels further; the lateral turbulent intensity continues to decrease with increasing c.
 Publication:

ASME Journal of Fluids Engineering
 Pub Date:
 September 1976
 Bibcode:
 1976ATJFE..98..506R
 Keywords:

 Axisymmetric Flow;
 Contraction;
 Free Flow;
 Kinetic Energy;
 Low Level Turbulence;
 Wind Tunnels;
 Flow Geometry;
 Flow Measurement;
 Flow Velocity;
 Incompressible Flow;
 Inviscid Flow;
 Screen Effect;
 Turbulent Flow;
 Fluid Mechanics and Heat Transfer