Uncertain solutions and multiple steady states in the built ventilation flows

Abstract

In past decades, several peers and not too many publications have reported that uncertain solutions existed in the building ventilation flows. In the present work, numerical, theoretical and experimental researches have been jointly applied for the non-unique flow solutions occurring in the built environment, covering from thermal driven flows, pressure driven flows and multi component flows. General multiple steady flows could be observed when different initial conditions were imposed. Independent flow branch could switch from each other during the critical point or some sudden transitions were imposed. Theoretical solutions could give rough routes for multiple flows, whereas numerical ones could give such detailed transitions delicately. Experimental model results well demonstrated those theoretical and numerical results. Future low carbon ventilation engineering applications could benefit from present fundamental researches.