Affiliation:
1. Department of Mathematical Sciences, University of Durham, Durham City DH1 3LE, UK
Abstract
Adoption of the hyperbolic Cattaneo–Christov heat-flow model in place of the more usual parabolic Fourier law is shown to raise the possibility of oscillatory convection in the classic Bénard problem of a Boussinesq fluid heated from below. By comparing the critical Rayleigh numbers for stationary and oscillatory convection,
R
c
and
R
S
respectively, oscillatory convection is found to represent the preferred form of instability whenever the Cattaneo number
C
exceeds a threshold value
C
T
≥8/27
π
2
≈0.03. In the case of free boundaries, analytical approaches permit direct treatment of the role played by the Prandtl number
P
1
, which—in contrast to the classical stationary scenario—can impact on oscillatory modes significantly owing to the non-zero frequency of convection. Numerical investigation indicates that the behaviour found analytically for free boundaries applies in a qualitatively similar fashion for fixed boundaries, while the threshold Cattaneo number
C
T
is computed as a function of
P
1
∈
[
10
−
2
,
10
+
2
]
for both boundary regimes.
Subject
General Physics and Astronomy,General Engineering,General Mathematics
Cited by
26 articles.
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