Transient stratifying process of a contained fluid with a vertical through-flow

Abstract

Two subjects which are involved in the method of producing a stratified fluid with a vertical through-flow are dealt with in this paper. (Figure 1.) One of the most efficiency and simplest method to stratify a fluid in a finite container is to place a fluid between two horizontal conducting plate, give an incompletely conducting sidewall, apply vertical temperature difference stably (hot above cold), and pump a small vertical through-flow up to the container through the bottom plate. It is well-known that this through-flow M causes a boundary layer at the vertical sidewall of a buoyancy layer type, gradually activates this layer, and finally, in the steady state, most of the imposed through flow M goes through the container via this layer. As a first subject, the stratification process when the imposed through-flow includes a pulsating component, i.e., M=Mo(1+ sin( t)) was concerned. How the time-dependent part of the through-flow affects the whole flow or temperature fields was observed. Especially, it was interesting to look into the possibility of a kind of resonance when the forcing frequency is very close to the characteristic frequency of the system. Second, the through-flow was pumped up into the container through the small hole at the bottom plate, and went out through the small hole at the top plate. The main concern here was whether we can obtain a stably stratified fluid with an almost stagnant interior with a boundary layer at the sidewall by the imposed flow through this restricted part of the bottom plate like through the whole of the bottom plate. In this case, through-flux M wa set to be a constant.