Example 11.29.  Show that the mapping  [Graphics:Images/FluidFlowImageMod_gr_7.gif]  maps the upper half plane [Graphics:Images/FluidFlowImageMod_gr_8.gif]  onto the domain in the w-plane that lies above the boundary curve consisting of the rays  [Graphics:Images/FluidFlowImageMod_gr_9.gif] and the segment  [Graphics:Images/FluidFlowImageMod_gr_10.gif]   (see Figure 11.87).

[Graphics: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  [Graphics:../Images/FluidFlowImageMod_gr_27.gif]  and integrate it to construct  f(z).

[Graphics:../Images/FluidFlowImageMod_gr_28.gif]




[Graphics:../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_30.gif]




[Graphics:../Images/FluidFlowImageMod_gr_31.gif]

 

 

 

Now solve for the coefficients  A  and  B.

[Graphics:../Images/FluidFlowImageMod_gr_32.gif]




[Graphics:../Images/FluidFlowImageMod_gr_33.gif]

 

 

 

Unfortunately, the branch cuts don't work out right and we will have to do this one by hand.

[Graphics:../Images/FluidFlowImageMod_gr_34.gif]


[Graphics:../Images/FluidFlowImageMod_gr_35.gif]

 

 

Using this formula in the book we form the two branches of the function.  

[Graphics:../Images/FluidFlowImageMod_gr_36.gif]


[Graphics:../Images/FluidFlowImageMod_gr_37.gif]

 

 

Use Mathematica to graph conformal mapping  w = f(z).

[Graphics:../Images/FluidFlowImageMod_gr_38.gif]




[Graphics:../Images/FluidFlowImageMod_gr_39.gif]

[Graphics:../Images/FluidFlowImageMod_gr_40.gif]

 

 

 

[Graphics:../Images/FluidFlowImageMod_gr_41.gif]




[Graphics:../Images/FluidFlowImageMod_gr_42.gif]

[Graphics:../Images/FluidFlowImageMod_gr_43.gif]

 

 

 

We have shown that the mapping  [Graphics:../Images/FluidFlowImageMod_gr_44.gif]  maps the upper half plane [Graphics:../Images/FluidFlowImageMod_gr_45.gif]  onto the domain in the w-plane that lies above the boundary curve consisting of the rays  [Graphics:../Images/FluidFlowImageMod_gr_46.gif] and the segment  [Graphics:../Images/FluidFlowImageMod_gr_47.gif].    

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_48.gif]




[Graphics:../Images/FluidFlowImageMod_gr_49.gif]

[Graphics:../Images/FluidFlowImageMod_gr_50.gif]

 

 

 

[Graphics:../Images/FluidFlowImageMod_gr_51.gif]




[Graphics:../Images/FluidFlowImageMod_gr_52.gif]

[Graphics:../Images/FluidFlowImageMod_gr_53.gif]

 

 

Also, we have shown that the mapping  [Graphics:../Images/FluidFlowImageMod_gr_54.gif]  maps the upper half plane [Graphics:../Images/FluidFlowImageMod_gr_55.gif]  onto the domain in the w-plane that lies above the boundary curve consisting of the rays  [Graphics:../Images/FluidFlowImageMod_gr_56.gif] and the segment  [Graphics:../Images/FluidFlowImageMod_gr_57.gif].    

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(c) 2006 John H. Mathews, Russell W. Howell