Rapid distortion of homogeneous turbulence between cylinders
American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FED
Cylinder, Hot-wire anemometer, Perforated plate, Rapid distortion, Turbulence intensity, Turbulence scale
The effects of 'half-full-half cylinders on the distortion of a turbulent flow are experimentally investigated. A single hot-wire anemometry unit is used to measure the stream-wise parameters of the flow. The cylinders are 15.2 cm (6 in) in diameter and 76.2 cm (30 in) in height installed in a closed loop wind tunnel with a 76.2 cm by 76.2 cm (30 in by 30 in) cross section. Turbulent flow with a nominal mean velocity of 7.6 m/s was generated by means of a perforated plate situated at the entrance of the wind tunnel. It was found that the mean velocity increases significantly as the flow passes through the contracting passage created by the cylinders, whereas the rms turbulence intensity decreases about 12% but shows an increase of up to 14% very close to the full cylinder. As the flow was distorted, the Kolmogorov length scales were elongated in the stream-wise direction, resulting in a decrease in the rate of turbulence decay which appears as a decrease in energy dissipation rate. The stream-wise integral length scales also increased due to the elongation of eddies in the stream-wise direction. Also, analysis of the turbulence fluctuating velocity in the frequency domain showed a redistribution of stream-wise turbulence kinetic energy from large to small scales during the distortion. Copyright © 2004 by ASME.
Emami, Babak; Liu, Rui; Ting, David S.K.; and Checkel, M. David. (2004). Rapid distortion of homogeneous turbulence between cylinders. American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FED, 260, 569-575.