Steady flow about a sphere in a porous medium subject to an oscillating temperature
The study of free convection about a sphere in a porous medium, when the temperature of the sphere is oscillating harmonically is considered for Rayleigh number, Ra=100. By using the matched asymptotic expansion, the flow field is divided into an inner region and an outer region, where the inn...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Penerbit UTHM
2011
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| Subjects: | |
| Online Access: | http://eprints.uthm.edu.my/7975/1/J3978_36d35d514b051f97574d9b91b9483d07.pdf http://eprints.uthm.edu.my/7975/ |
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| Summary: | The study of free convection about a sphere in a porous medium, when the
temperature of the sphere is oscillating harmonically is considered for Rayleigh
number, Ra=100. By using the matched asymptotic expansion, the flow field
is divided into an inner region and an outer region, where the inner region is
adjacent to the sphere and the outer region is far from the sphere. In the inner
region, the separation technique is used to divide the second-order temperature
and stream function into steady and unsteady parts. The analytical solution is
obtained up to second-order steady term. For outer region, the numerical result
up to first order is obtained by using a finite difference scheme. It is found that, a
steady flow is induced at the outer edge of the inner region. The temperature and
flow patterns are discussed and compared for some frequencies of oscillation,
ω and dimensionless parameter ε. It is found that both the magnitudes of
temperature and stream functions decreases as ω increases or decreases but
the effect of ε is not significant in the outer region. In the inner region, the
magnitude of steady flow is also determined by frequency. |
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