The invention relates to a method for mixing a static fluid with another component, such as a particulate material, a liquid, a compressible liquid or gas, or combinations thereof, using a motive fluid stream, producing a low pressure region within the static fluid using radial eductors in a tank. The invention further relates to a method for separating oil form an oil and water mixture using a motive fluid stream and air, producing a low pressure region in a tank with entrained air bubbles, wherein the oil attaches to the air bubbles and rises to the surface.