Heat flux with oscillating heat sink

[tempneff]

I am curious about the effects of oscillation in a heat transfer system. For example consider a simple system consisting of a heat source, a heat sink, and some generic material through which we will flow heat.

http://tempneff.com/Hflux.png

If we stack them all together, without thermal grease or other treatments, then they should transfer heat by \frac{Q}{t}=\frac{\kappa A(T_{hot}-T_{cold})}{d}

where Q= heat transferred, t=time, \kappa = thermal conductivity of barrier, A = area, T= temp, and d=thickness of barrier. Right?

What would be the effect if I were to vibrate the cold side? Instinctively I thought it would interrupt heat flow decreasing Q/t, but I am reading (unless I misunderstand) that sometimes heat transfer is improved by oscillation.

Any thought?

 

[Seth.T]

If i understand you correctly, I think the logic is similar to having a fan blowing to the heatsink on the other end, decreases Q/t because it increases heat dispersion thus improves natural convection on the outer surface, therefore improve Heat flux to surrounding.

 

[tempneff]

I'll buy that. I still wonder about the magnitude of effect from other dynamics. At high frequency would the friction created have a noticeable effect on the net flux? What about the change in surface area when part of the cold block is shifted off of the 'material'?

 

[Seth.T]

Higher frequency means more oscillation, so its similar to a higher RPM fan which gives better cooling measure..