A passive method for setting up a density gradient

In this paper, a passive method is introduced for establishing an arbitrary density profile in a container of a given arbitrary shape. Liquid is withdrawn using gravity from the bottoms of two tanks, one containing lower density liquid and the other containing higher density liquid. The liquids withdrawn from the two tanks are then mixed through a pipe which feeds the product gently to the bottom of a third tank in which a pre-specified density profile is required. The cross section of one of the filling containers is assumed to be uniform. The second filling container must be shaped in such a way that allows the desired density profile in the third container to form.