have you ever heard of "fluidic thrust vectoring"? or, the "coanda effect"?
from the notes prepared by my lecturer, the "fluidic thrust vectoring" is the process of altering the direction of an exhaust jet utilizing fluidic means, i.e. without mechanical intervention. interesting eh? doesn't it? la, dont say you blurr lah..
ok, thrust vectoring is a technique whereby the orientation of the primary exhaust jet from a propulsive unit is varied in order to provide useful aircraft control moments. in a mechanical system, changes in nozzle geometry are used to generate the vectoring. on the other hand, fluidic thrust vectoring systems use a secondary air jet to control the direction of the primary jet. in contrast to mechanical systems, fluidic systems have the advantages of being lightweight, simple, of fixed geometry and can be implemented with minimal aircraft observability penalty.
let's see the picture here;
this is the theory, on how the system work
let us see another picture of the experiment;
as you see in the previous pic, there is primary (larger flow area) and secondary flow (smaller flow area).. and this picture is showing a jet flow, flowing through the primary flow space only.
and this picture is taken after another jet flow flowing ...