|
One of the most important problems is how to control boun- dary-
layer separation for aerodynamists. In this treatise, we try to
give a new suggestion to this problem: introducing an
artificial body force to the original boundary layer. This idea
came from Prof. Chiu, and he named this under-developing con-
trol system as the "Mini-Propulsion System". As a beginning,
we want to build a mathematical base for this idea: using an
idealized accelerating model with a known distribution
function, then find the changes of flow by the computational
simulation. First, solving an analytical flow field -- wedge
geometric flow with similarity forcing, we found the possibly
better types of forcing distribution function. Then, we tried
to deal with the recirculation region behind the blunt body. We
simulated the problem: a uniform flow over a sphere . Choosing
three different positions under various pressure gra- dient
conditions, and forcing the fluid particles near the boundary
layer region with five kinds of forcing distribution function.
We have had the results : under some special matches in the
forcing function and position, we can have the shortened
recirculation zone, the separation occurrence being delayed and
great drag reduction as expect.
|