Bv. Antohe et Jl. Lage, A DYNAMIC THERMAL INSULATOR - INDUCING RESONANCE WITHIN A FLUID-SATURATED POROUS-MEDIUM ENCLOSURE HEATED PERIODICALLY FROM THE SIDE, International journal of heat and mass transfer, 37(5), 1994, pp. 771-782
This theoretical and numerical study investigates the natural convecti
on flow within a fluid saturated porous medium enclosure subjected to
intermittent heating from the side (hot wall). A theory for predicting
the natural convection frequency of the flow wheel circulating inside
the enclosure is developed from the general porous medium equations o
n a scaling basis. Physical insight indicates that heat flow resonance
might occur when the input heat frequency matches the flow wheel circ
ulating frequency. Numerical simulations confirm the existence of a pr
eferred (resonance) input heat pulsating frequency. They also reveal t
hat at the resonance frequency the fluid saturated porous medium syste
m behaves as a dynamic thermal insulator in which the strong natural c
onvection activity within the system, characterized by high amplitude
heat flow oscillations, coexists with a damped oscillatory heat flux a
t the isothermal (cold) wall.