Variable property effects in the direct numerical simulation of a convective channel flow
The effects of the introduction of variable viscosity and thermal conductivity into a turbulent channel flow have been investigated by means of a direct numerical simulation. Results from a constant property simulations for air (Pr = 0.72) exhibit good agreement with experimental data and other simulations. Results from a variable property simulation for water (Pr = 5.8) are presented and compared to the constant property case. The Reynolds number, based on channel half-weight and initial centerline velocity, was 4,200. The results indicate that the inclusion of variable properties has the following effects on the flow field; the mean velocity profile is asymmetric, its maximum value is offset towards the region of lower average viscosity; the RMS velocity fluctuations are smaller in the region of flow with lower average viscosity, with minima in the same position as the maximum of the mean velocity profile; the peak value for Reynolds stress has a lower magnitude in the region of lower average viscosity, and the point of zero Reynolds stress is as the same location as the maximum of the mean velocity profile; the RMS temperature fluctuations are asymmetric, with a maxima occurring at the same position of maximum mean velocity; the temperature-velocity correlation in the flow direction is asymmetric with a value of zero at the same position as the maximum of the mean velocity. These results indicate that the variation of thermal conductivity and viscosity as functions of temperature have significant effects on the flow field.
- Research Organization:
- Univ. of Wisconsin, Milwaukee, WI (US)
- OSTI ID:
- 20002514
- Report Number(s):
- CONF-990805--
- Country of Publication:
- United States
- Language:
- English
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