Controlling the motion of a fluid jet

A method of mixing first and second fluids, comprising:

• admitting the first fluid into a chamber as a flow which separates from the chamber wall structure;
• and
• allowing the separated flow to reattach itself asymmetrically to the chamber wall structure upstream of an outlet of the chamber disposed generally opposite the admitted flow, and to exit the chamber through the outlet asymmetrically;
• whereby a reverse flow of the first fluid at said reattachment and a flow of the second fluid induced from the exterior of the chamber through said outlet combine to swirl in the chamber between said flow separation and said reattachment and thereby induce precession of said separated/reattached flow, which precession enhances mixing of this flow with the second fluid to the exterior of the chamber.

A fluid flow control device, comprising:

• wall structure defining a chamber having a fluid inlet and a fluid outlet disposed generally opposite the inlet;
• said chamber being larger in cross-section than said inlet at least for a portion of the space between said inlet and outlet;
• flow separation means to cause a flow of a first fluid wholly occupying said inlet to partially separate from said wall structure upstream of the outlet;
• wherein the distance between the flow separation means and said outlet is sufficiently long in relation to the width of the chamber for the partially separated flow to induce a second flow from the exterior of the chamber through said outlet and for this second flow to influence the partially separated flow whereby the latter exits the chamber asymmetrically in a direction toward the same side of the chamber as the flow separation.

Combustion apparatus having a combustion nozzle with a fluid mixing device comprising:

• wall structure defining a chamber having a fluid inlet and a fluid outlet disposed generally opposite the inlet;
• said chamber being larger in cross-section than said inlet at least for a portion of the space between said inlet and outlet;
• flow separation means to cause a flow of a first fluid wholly occupying said inlet to separate from said wall structure upstream of the outlet;
• wherein the distance between said flow separation means and said outlet is sufficiently long in relation to the width of the chamber for the separated flow to reattach itself asymmetrically to the chamber wall structure upstream of the outlet and to exit the chamber through the outlet asymmetrically, whereby a reverse flow of said first fluid at said reattachment and a flow of a second fluid induced from the exterior of the chamber through said outlet swirls in the chamber between said flow separation and said reattachment and thereby induces precession of said separated/reattached flow, which precession enhances mixing of the flow with said second fluid to the exterior of the chamber.