Example 11.29. Show
that the mapping
maps
the upper half plane
onto
the domain in the w-plane that lies above the boundary curve
consisting of the rays
and the segment
(see
Figure 11.87).
![[Graphics:Images/FluidFlowImageMod_gr_12.gif]](../Images/FluidFlowImageMod_gr_12.gif)
Figure 11.87 (a) Flow over a step. (b) Flow around a blunt object.
Explore Solution 11.29.
Use the Schwarz Christoffel formula, enter the
formula
and
integrate it to construct f(z).
![[Graphics:../Images/FluidFlowImageMod_gr_29.gif]](../Images/FluidFlowImageMod_gr_29.gif)
This is one, formula for the integral. However, we will use the following form of the integral to continue the computations.
![[Graphics:../Images/FluidFlowImageMod_gr_31.gif]](../Images/FluidFlowImageMod_gr_31.gif)
Now solve for the coefficients A and B.
![[Graphics:../Images/FluidFlowImageMod_gr_33.gif]](../Images/FluidFlowImageMod_gr_33.gif)
Unfortunately, the branch cuts don't work out right and we will have to do this one by hand.
![]()
Using this formula in the book we form the two branches of the function.
![[Graphics:../Images/FluidFlowImageMod_gr_37.gif]](../Images/FluidFlowImageMod_gr_37.gif)
Use Mathematica to graph conformal mapping w = f(z).
![[Graphics:../Images/FluidFlowImageMod_gr_39.gif]](../Images/FluidFlowImageMod_gr_39.gif)
![[Graphics:../Images/FluidFlowImageMod_gr_40.gif]](../Images/FluidFlowImageMod_gr_40.gif)
![[Graphics:../Images/FluidFlowImageMod_gr_42.gif]](../Images/FluidFlowImageMod_gr_42.gif)
![[Graphics:../Images/FluidFlowImageMod_gr_43.gif]](../Images/FluidFlowImageMod_gr_43.gif)
We have shown that the mapping
maps
the upper half plane
onto
the domain in the w-plane that lies above the boundary curve
consisting of the rays
and the segment
.
We are done.
Aside. Here is another
function that produces the desired result. The graph is
drawn parametrically in this case.
![[Graphics:../Images/FluidFlowImageMod_gr_49.gif]](../Images/FluidFlowImageMod_gr_49.gif)
![[Graphics:../Images/FluidFlowImageMod_gr_50.gif]](../Images/FluidFlowImageMod_gr_50.gif)
![[Graphics:../Images/FluidFlowImageMod_gr_52.gif]](../Images/FluidFlowImageMod_gr_52.gif)
![[Graphics:../Images/FluidFlowImageMod_gr_53.gif]](../Images/FluidFlowImageMod_gr_53.gif)
Also, we have shown that the mapping
maps
the upper half plane
onto
the domain in the w-plane that lies above the boundary curve
consisting of the rays
and the segment
.
