| Summary: | 碩士 === 逢甲大學 === 土木及水利工程研究所 === 81 === In this paper, a special 2D field of viscous transient flow
past a circular cylinder close to a planewas studied. A
horizontal plane (line) was used as thelower boundaryof the
field , and a circular cylinder (circle) was place near and
above the plane with a "gap"between the cylinder and the
plane. Two numericalmodels has been used in this paper. The
first one was incompressible flow model. Body-fitted
coordinate systemand finite difference method were adopted for
thedevelopmentof the model. Since this model was divergedas
the cylinder was very closed to the plane, the secondmodel was
developed, i.e.compress- -ible flow model.Results showed that:
1) main flow is upraise as it passesthe cylinder; the velocity
of the gap flow is decreasing with time; the separation region
of the cylinder and theplane boundary are appeared; the lift
coefficient wastowared a periodic configuration; the drag
coefficient isincreasingslowly. 2) At the small distance of
the gap,the flow field iseasier to steady state; the scale
ofthe separation on the cylinder and the plane is biggerthan
others; the drag and the lift coefficient is increasing
rapidly. 3) In different Reynold numbers,the flow field is
similar; the separation on the planeis increasing with time;
the drag and the liftcoefficient is incressing with time, and
the value ofsmall Reynold number is bigger than others.
|
|---|
